457975 Wheel End Maintenance Guide
Contents
1. Wheel end maintenance Complete guide to trouble free handling of bearings seals hubcaps lubricants and more A systems approach to total wheel end mar SKF s Trouble Free Operation TFO Program Hes is a proven systems approach to heavy duty ea maintenance By providing fleets with Bm detailed instructional materials and f making hands on training available rotate FREE PER to your technicians this program has made a significant MINNS contribution to many fleets overall productivity Mi ii This Wheel end maintenance guide central to the i TFO program is based on our core experience with bearings and seals over several decades and literally billions of over the road truck miles Through our investigation of thousands F of premature seal leaks and or bearing failures weve learned that improper removal and installation are by far the leading causes of these premature failures Armed with the right information and tools and using the step by step procedures in this manual you can extend the service life of bearings and seals protect your trucks from costly damage and make your fleet safer in the process About TFO k e Why a systems approach e Extended warranties e Program overview e General guidelines Product overview e Seals e SKF tapered bearings e ConMet PreSet wheel ends e Hubcaps e Lubrica2. pre assembled retention bolts included protect against leaks at the bolt holes Lightweight Proven center fill super strong vented plug design closed Magnetic side fill Zytel resists except when venting plug traps metal impact damage particles to protect chemicals road Upgraded Splashguard seals and bearings salt UV radiation protection also available flooded docks and ozone Cloud free window is fusion bonded to body no screws to shake loos and no leaking O ring on the side fill plug provides extra leak protection Molded pressure ridge on flange serwer Oil bath design leak proof fit Slotted bolt hole gasket S K F S p las h e uard Embedded solid aluminum Upgraded vent system and protection ond ARDE A leak proof load against Multiple labyrinth Elongated bolt holes menue accommodate multiple Hard shell l prevents contaminants bolt circle patterns resists power washing from reaching wheel end road debris Side tabs allow for easy removal compatible type Extended surface adds coverage between window plug for better sealing Pressure sensitive vent vent closed unless releasing pressure Grease Oil bath eliminates entry path for contaminants packed type type 16 The importance of proper lubricants Running conditions Road surface weather terrain speed and load Lube on the brakes Hardening or destruction of
3. see pages 20 thru 26 Installation procedures D Bearing cups should be installed using a special bearing installa tion tool A hammer should never be used directly to drive bearing cups into position F Scotseals should be seated in the bore using a special instal lation tool with centering plug Never use direct hammer blows on the seal it will destroy the seal s ability to contain lubricants and protect the bearings F Re mounting of the wheel assembly on the spindle should always be done using a wheel dolly Be careful in moving the assembly onto the spindle because it is necessary to avoid damaging the seal G Spindle nut torque adjustment should follow the manufacturer s specification on TMC RP618 End play adjustment should be verified using a portable dial indicator A SKF Scotseal for every application Scotseal PlusXL The Scotseal PlusXL design with extended life capabilities is the SKF premium performance seal offering maximum sealing life under virtually all driving conditions The new high temperature synthetic lubricant friendly material of the new Scotseal PlusXL Hydrogenated Nitrile Butadiene Rubber HNBR is an excellent choice for frequent braking applications HNBR elastomeric material provides heat resistance up to 300 F and broad compatibility with today s synthetic lubrication fluids The unsurpassed exclusion properties allow the Scotseal PlusXL to perfo
4. 2011 ConMet does no See an i iS ala iin che nut a not recommend the use of a one piece castellated ON t lbs Uo not back off the spindle type nut system for use with PreSet hubs nut Advance the nut until engagement takes place and the nut is locked 25 Wheel bearing end play verification Wheel bearing end play is the free movement of the wheel assembly along the spindle axis It is recommended for verification purposes that wheel bearing end play be measured with a dial indicator Example in photo below Step 1 Step 2 Step 3 Step 4 Step 5 Make sure the brake drum to hub fasteners are tightened to the manufacturers specifications Attach a dial indicator with its magnetic base at the bottom of the hub or brake drum Adjust the dial indicator so that its plunger or pointer is against the end of the spindle with its line of action approximately parallel to the axis of the spindle Note For aluminum hubs attach the magnetic base of the indicator to the end of the spindle with the plunger against the hub or brake drum Set the dial indicator to zero by rotating the gauge face so the zero mark lines up with the gauge needle For digital indicators push the zero out button Grasp the wheel assembly at the 3 o clock and 9 o clock positions while oscillating it to seat the bearings Read bearing end play as the total indicator movement Note f end play is not within specifications refer to the readjustment proce
5. 28 58 Matchup of bearing cones amp centering plugs eE 445 46308 28820 36358 39380 452 28832 Bearing Centering Bearing Centering Bearing Centering cone no plug no cone no plug no cone no plug no ee Scie Soo pees pax op TT TST 75 2850 4263043764 539 701 7495 719 15284 700 31244 4267 2 42631 43765 noO R E E ga Ro me ue io 703 3 R B ZE m H uao 5200 39380 567 T 776 715 47687 710 31307 43865 52664 w disc em me BR Busy 708 580 710 3982 704 JH21 7249 719 paren ines Lee en 582 710 3984 706 JM205149 A 722 593 712 4595 701 JM207049 A Ta 47693 48297 40139 484 594 Tae 5557 ed JM511946 724 47696 48298 40146 44922 594A TAS 5760 708 JM716649 719 LAGOT 48690 40147 o 595 710 6379 705 JM718149 A 4 7698 42792 596 711 6386 706 JM719149 Re 42000 18794 461 45010 598 714 6386A 706 HM212044 703 45152 45099 598A Tile 6389 706 HM212046 704 436 48796 45160 45100 639 704 6461 708 HM212047 704 34975 48884 MEA 45103 641 706 6461A 708 HM212049 X 706 35000 50124 13163 151028 659 708 6559 710 HM212049 706 35001 L48 663 710 6580 712 HM215249 707 462 42625 663A 710 28995 703 HM218248 713 35060 30709 eye 664 732 33281 716 HM516449 710 35066 39988 29760 665 14 2 707 HM518445 al 35072 39990 665A 711 33895 701 H715345 Wal 35075 38780 483 re a T TE 715 687 me 39581 702 35103 38783 23 Installing hub assembly Do not attempt to install the hub assembly by hand Whether the hub is with or without the tire do not install it without mechani
6. D beads Damaged 0 D beads If the external ridges appear damaged most likely someone has tried to force the seal in place without proper lubrication Burrs or dirt in the bore can also cause problems but they re not as visible with the thick nitrile rubber protection Dry exterior If in good illumination you cannot see any residual lubrication between the beads of the outer sleeve the seal may have been installed dry A Scotseal PlusXL does not need special tools but it does need lubrication for proper installation Worn D beads A worn D indicates the seal has been slipping on the spindle Look for three main causes a cocked seal a bent seal section or poor spindle preparation in changing from another seal to the Scotseal PlusXL Damaged D beads Cuts or scarring in the I D is caused by jamming the seal into the spindle or axle tube Misaligning the wheel dolly is usually the result of haste however the work area should be checked to make sure the floor is smooth and free of clutter Dented scarred sleeve assembly A dimpled or dented surface indicates damage caused by a problem during installation Lack of lubrication would be a prime suspect but a poorly prepared hub or the use of hard faced tools or seal driver could be the culprit SO Failure analysis Scotseal PlusXL Opening a Scotseal PlusXL ek Vee Use pliers to straighten the flange on the sleeve Pull th
7. SKF quality in one convenient box ConMet introduced the PreSet hub assembly in 1995 And since 2002 the SKF Scotseal PlusXL has been the primary wheel seal in the OE wheel end system Now that these units are approaching their first service intervals SKF the aftermarket leader worked closely with ConMet to provide the only all inclusive rebuild kit on the market SKF rebuild kits contain everything needed for servicing including specific tighter toleranced SKF tapered bearing sets SKF Scotseal PlusXL wheel seal SKF TF hubcap if applicable and precision machined PreSet bearing spacer SKF half stand tapered bearing sets 2 e Original equipment approved e Precision manufactured with dimensional tolerances specified by ConMet e Superior design and materials reduce friction and provide excellent reliability under heavy loads and misaligned conditions e Global OE supplier CONS ap T Pointing the Way SKF Scotseal PlusXL e The most advanced generation Scotseal standard in PreSet hub assemblies since 2002 e Hydrogenated Nitrile Butadiene Rubber HNBR construction is ideal for frequent braking applications e Heat resistance up to 300 F compatible with synthetic lubricants e Excellent exclusion properties even in harsh conditions e Hand installable design includes a fat footprint ensuring stability on the shaft 14 Why install the kit instead of off the shelf components While you co
8. a radial and axial dirt lip plus an outer bumper lip that acts as a preliminary dirt excluder Scotseal PlusXL requires no special installation tools and maintains a rubber to metal contact between the seal O D and the hub bore surface as well as a rubber to metal contact between the packing I D and spindle See Figure 1 SKF Scotseal Longlife is a unitized one piece design consisting of a sealing element packing that is assembled between a metal outer and inner case The Scotseal Longlife s packing consists of four sealing lips a spring loaded primary sealing lip that is factory pre lubed a radial and axial dirt lip plus an outer bumper lip that acts as a preliminary dirt excluder The Scotseal Longlife is pressfit into the hub bore using Scotseal Installation Tools The Scotseal Longlife maintains a metal to metal contact between the seal O D and the hub bore surface as well as a metal to metal contact between the packing D and the spindle See Figure 2 SKF Scotseal Classic is a unitized one piece design consisting of a sealing element packing that is assem bled between a metal outer and inner case The packing consists of three sealing lips a spring loaded primary sealing lip that is factory pre lubed a dirt exclusion lip and an outer bumper lip that acts as a preliminary dirt excluder The seal is pressfit into the hub bore using Scotseal Installation Tools The Scotseal Classic maintains a metal to metal con
9. also play a role in the correct or 5 incorrect installation process Tooling Professional training of the shop personnel is the silver bullet to improved maintenance efficiency and the reduction of premature seal and bearing failure To put training in its proper perspective as much as 90 of all wheel end seal failures are a result of improper installations Training TFO solution SKF recognizes the need for more than one type of seal for every purpose The TFO Program analyzes seal matchup to your fleet s needs and recommends the optimum seal selection for your operation The TFO Program details the proper removal and installation of bearings including procedures for cleaning lubricating and assuring correct end play adjustment SKF offers replacement hubcaps that are approved by all major OE truck and most trailer builders and are compatible with all popular oils and greases The TFO program outlines the importance of proper hubcap installation and details the process of matching the correct hubcap with the lubricant being used on a specific application Over the years SKF has examined thousands of damaged seals from all manufacturers and has analyzed the major causes of the damage This knowledge has been distilled into our documentation called Failure Analysis Part of the TFO Program includes inspection and analysis of your fleet s wheel end failures and a recommendation of steps needed to avoid similar
10. failures in the future SKF s specialized tooling is designed for errorless damage free removal and installation of seals with procedures that can be easily understood These tools and the training on how to use them properly are part of the TFO Program s implementation process The TFO Program puts appropriate emphasis on training with the goal of issuing TFO Qualified certificates to participating shop maintenance personnel Training is conducted by knowledgeable and experienced SKF personnel with hands on learning tooling demonstrations videos and User Manuals Education on the importance of wheel end systems and their critical role in the safety and productivity of the vehicle is an important part of the TFO Program implementation General procedure overview Basic guidelines of the TFO procedures for removal For more detailed information see pages 18 and 19 Removal procedures Removal of the wheel assembly should always be done with a wheel dolly Grease or oil seals should be removed with a special seal removal tool to avoid damage to the hub New seals must always be used in replacement Bearings seals and all wheel end components should be inspected for wear or signs of probable failure These signs and the likely causes of failure are described in the Failure Analysis section of this manual Basic guidelines of the TFO procedures for installation For more detailed information
11. of a sharp object like a screwdriver or punch 29 Failure analysis Scotseal Classic Scotseal Longlife Reference the Scotseal installation wall poster 457626 as a convenient seal and bearing installation guide External inspection inner diameter I D wear If the D of the packing is shiny or has axial scratches the seal has spun on the shaft That can be caused by not bottoming out the seal properly leaving it cocked in the bore or installing the wrong part number Severely damaged D Scratches or dents in the D are signs that the seal has struck the spindle or axle tube during installation Rushing the installation and not lining up the wheel dolly is the usual suspect Or a rough shop floor may be the problem Installed backwards The only way that the packing can be worn shiny as shown here is by rubbing against the bearing race The only way that can happen is by putting the seal in backwards Distorted packing One way to damage the packing of a Scotseal is to try to install it over a wear ring he wear ring will deform the inner surface and ruin the seal Any previously installed wear ring must be removed prior to installing a Scotseal Foreign matter on I D Occasionally you will come across a seal with a shaft leak that has a mysterious tacky substance on it Most likely someone added a silicone sealant to improve the seal Old habits die hard Failure analys
12. profitable For the latest information please visit our online catalog at www vsm skf com or contact your local SKF representative at 1 800 882 0008 To receive updates and news from SKF please email vsm updates skf com SKF is a registered trademark of the SKF Group SKF Group 2012 The contents of this publication are the copyright of the publisher and may not be reproduced even extracts unless permission is granted Every care has been SKF VSM taken to ensure the accuracy of the information contained in this publication but 890 N State Street no liability can be accepted for any loss or damage whether direct indirect or Suite 200 consequential arising out of the use of the information contained herein Elgin IL 60123 Publication 457975 rev 05 12 800 882 0008 Printed in U S A www vsm skf com
13. seated Continue driving the seal into the hub until the sound of impact changes 4 After the seal is bottomed in the bore check for freedom of movement by manually moving the packing of the seal up and down Ensure that the inner bearing rotates freely Caution Install a new seal if the seal is cocked or damaged during or after installation The Scotseal toolboard e Keeps tools orderly and lessens chances of tools being misplaced or damaged Sturdy metal construction mounts easily on shop wall e Fitting chart included e Just order Part No TB 2 Installation tooling Scotseal Classic Scotseal Longlife Standard plug bushing Washer Standard tool handle 450237 Centering plug Nut Seal drive plate These components are interchangeable See chart Tool selection aa SKF Scotseal Classic and Scotseal Longlife are to be installed using only SKF Scotseal installation tools See Chart A below Centering the seal Precisely matched centering plugs are engineered to fit within the inside diameter of the inner bearing cone and allow accurate centering of the Scotseal in the bore of the hub as well as preventing cocking of the seal Chart B below provides correct matchup of bearing cone and centering plug Chart A Drive plate amp seal matchups Drive plates in bold numbers with matching seal numbers 427 441 451 463 Chart B 34367 40086 46305 21438 86274 40090 46306
14. OSE as num Sg 200 300 beft 025mm 200 theft 50 ibeft aS g 271 407 Nem 127mm 271 Nem One full 68 Nem turn il hi Dowel type 300 400 lbeft Drive 1 4 Turn wheels wheels 16 Tang type 200 275 lbeft As measured washer 271 373 Nem per procedure with dial 12 2 5 8 f f o Trailer a vstum 66 7mm Grr ane i If dowel pin and washer or washer tang and nut flat are not aligned remove the washer turn it over and reinstall If required loosen the inner adjusting nut just enough for alignment aii Bendable type washer lock only Secure nuts by bending one wheel nut washer tang over the inner and outer nut Bend the tangs over the closest flat perpendicular to the tang Printed with permission of the TMC Reference RP618A PreSet wheel bearing adjustment procedure ConMet PreSet hub assemblies are equipped with specially half toleranced bearings and a spacer and require a specific bearing adjustment procedure Use the OEM seal Scotseal PlusXL when servicing a PreSet hub assembly 1 Lubricate the wheel bearing with clean axle lubri 2b For a double nut or jam nut system torque the inner cant of the same type used in the axle sump or nut to 300 ft lbs Do not back off the spindle nut hub assembly Never use an impact wrench when Install the outer nut with 200 ft lbs of torque aan or loosening lug nuts or bolts during this Note Be sure to engage any locking device 2a F nd h 2c Per ConMet Service Manual rev
15. ation Inspection of the inner ring often requires Examine the inner ring raceway by a sharp eye because the damage can be very subtle holding the bearing against a light and The most common types of fatigue damage are turning the cage slowly Look for pitting shown below flaking discoloration and corrosion Dirt Misalignment Insufficient lubricant er Failure analysis for bearings Improper bearing adjustment Large end of roller shows scoring the result of Large end of the roller shows spalling the excessive preload result of insufficient lubrication and or excessive preload Pitting Small end of the roller shows excessive wear Pitting of the race as a result of debris in the the result of loose bearing adjustment lube causing surface deformation Misalignment l Misalignment occurs when the center lines of the two bearings are not parallel to each other J rh The causes can be an improperly seated bearing where dirt or burrs prevent a flush mount an outer cup installed without the proper tool a warped shaft or nut faces that are out of line DEEE fu 40 Failure analysis for bearings Misalignment Uneven wear on the roller the result of improper installation Contamination Circular wear in the race the result of hard particle Vertical etching on the race the result of moisture contamination in the lube contamination within the lube Circular wear on the rol
16. brake hardware brake shoes e Verify end play measurement before removing fastener External leakage e Examine outer nut washer e Qil present around hubcap dowel tang or D type inner in wheel cavity nut cotter pin Oil present around axle flange drive axle Remove outer bearing f e Inspect for signs of damage Disassembling the wheel end Caution Block wheels support vehicle on stands Remove wheel or hub assembly using a wheel doll e Check condition of hubcap 9 y Check flange window and Check spindle centerfill plug e Threads damaged e Check bolts and axle flange area on drive axle e Chamfer damaged Set bearings aside for inspection Remove hubcap Axle flange on drive axle Remove seal e Check hub Check condition of lube e Cloudy or milky indicates e Condition of chamfer water e Nicks burrs damage e Shiny indicates bearing wear e Consult the Failure Analysis e Metal flakes present could section of the User s Manual indicate loose shavings from an axle component e Grit and sand indicates lube contamination The quality of SKF bearings Bearing sets SKF tapered bearings are engineered and manufactured to the highest quality standards Their design and superior materials provides a significant increase in operational reliability under heavy loads and misaligned conditions Made from the highest quality steel and engineered for longer service intervals the constructio
17. cal support Axle spindle shaft 1 When installing the hub assembly over the axle spindle be sure to align the hub bore to the center of the spindle Mechanical supports will allow you to do this without scraping or otherwise damaging the spindle the threads and in particular the seal DO Install the outer bearing cone and adjusting nut Tighten nut only until it is snug against the bearing cone DO NOT USE A PNEUMATIC TOOL during this part of the procedure Be sure to maintain support of the hub assembly until the adjusting nut is secure Failure to do so may cause damage to the seal and subsequent leakage of lubricant UO Remove the hub support so that the hub is resting on the bearings Check for free rotation of the bearings Never allow hub to rest on seal D Follow wheal bearing adjustment as instructed on following page 24 Wheel bearing and end play adjustment procedures Wheel bearing adjustment procedure Lubricate the wheel bearing with clean axle lubricant of the same type used in the axle sump or hub assembly Note Never use an impact wrench when tightening or loosening lug nuts or bolts during the procedure Initial a Final Sane Initial ee Acceptable eee HEH eee Axle type Threads Final Nut size Torque Te per inch back off specifications sep sus steps ses spe sep o 1 6 Turn Install cotter pin to lock Steer 1 4 Turn axle nut in position 001 front a 005 N
18. cants Installing bearing cup and seal Avoid any direct hammering on the bearing or the seal this will cause deformation or damage which will result in premature failure Use a simple vertical press to push the bearing cup into correct position in the hub For aluminum hubs prior to pressing bearing cup into the hub heat hub in oven at 250 300 F and chill bearing cup in freezer Use a recommended seal installation tool to set the seal correctly in the hub When hammering on the tool be sure to stop when the seal is bottomed Do not add extra blows or it will cause immediate damage to the seal Installation force Seal installation tool Seal must _ bottom in bore Note if the tire is mounted on the hub place the entire assembly against a solid surface at a s 45 angle before final setting Inner bearing cup Inner bearing cone 2 Installation procedures Scotseal PlusXL This seal is hand installable No special tools are required Caution Do not install the Scotseal PlusXL directly onto the spindle Place the hub wheel assembly flat or at least a 45 angle for seal installation Clean bore of any particles rust or grease 1 Pre lube the inner bearing cone with the lubricant that is being retained and place it into the hub 2 Lightly lubricate the seal O D and I D evenly with the Lightly lubricate the OD and ID A rubber mallet fluid that is being retained Also app
19. chased under the TFO program Scotseal Classic Scotseal Longlife Scotseal PlusXL 1 year or 2 years or 3 years or Teor 100 000 miles 150 000 miles 300 000 miles 1 year 2 years 3 years Severe 1 year or 1 year or 1 year or Service 50 000 miles 100 000 miles 150 000 miles The following conditions are required for warranty coverage under the TFO program e SKF hubcaps must be used e Coverage applies to genuine SKF Scotseals and Hubcaps only e User must follow current TMC maintenance procedures e SKF representative to conduct training at each fleet maintenance facility e Wheel end maintenance records are to be monitored by SKF and fleet Note For further details on the warranty program contact your local SKF representative Caution Beware of counterfeit seals Unscrupulous manufacturers are flooding the global market with poorly engineered and cheaply manufactured seals that have deliberately been made to resemble premium quality SKF Scotseals Most obvious is the use of green paint not Bore Tite that can flake off and enter the hub actually causing bearing damage The warranties detailed above apply only to genuine SKF brand Scotseals A few words of caution e A seals running surfaces are critical to performance Historically the running surfaces of counterfeit seals have been demonstrated to be well below SAE standards e Testing has shown these counterfeit seals to be of substantially inferior quality and highly questio
20. ction and failure analysis if required Bearing and seal installation Grease or oil General instructions seal Wheel hub designs differ from one manufacturer to another However the correct procedures for installing bearings and seals remain basically the same Care in handling components and proper tooling are always the critical factors in all procedures which lead to Trouble Free Operation Typical hub Inner bearing cone Outer bearing cone Inner bearing cup mounted in hub Components in a typical hub assembly Outer bearing cup mounted in hub 20 Bearings must be cleaned for inspection and can be re used Use only clean solvents effectiveness of solvent in removing old lubricant depends on how clean the solvent is Good cleaning requires proper equipment such as e Solvent bath e A filter system and regular changes of the solvent and the filters e Do not allow bearing to sit on bottom of container to avoid contact with sediment Remove bearing cup if it or the bearing cone require replacement e Ferrous hubs Use hydraulic press to remove cups e Aluminum hubs DO NOT USE hydraulic press Instead weld bead around the face of the bearing cup Allow to cool 15 minutes Remove by hand Oil lubricated wheel ends WT C O Coat the bearing cones with a light oil film before inserting them into the bearing cups Always use the specified oil for replacement and do not mix lubri
21. d areas that s normal But signs of nicks scratches metal particles or any foreign material are warning flags that something else is amiss Make sure the hub bore is smooth and free of burrs or nicks External inspection outer diameter 28 0 D radial grooves If the Bore Tite film has been scored all the way across the width of the seal you should inspect the hub for burrs or damage Before installation the hub should be inspected and cleaned with emery cloth or a fine file Lines in the Bore Tite If you see lines around the seal several things could have happened If the lines are etched to the metal the seal could have spun as a result of being the wrong application or more likely it was installed crooked or cocked As you can see in this example the grooves run from high on the left to low on the right indicating a cocked installation Most likely the seal was not properly bottomed out or a centering tool was not used common causes of premature seal failure Shiny leading edge Occasionally someone will try to improve seal installation by changing the shape of the seal They ll round off the leading edge of the outer cup on a grinder This distorts the outer diameter and can possibly cause the seal to disassemble Outer cup damage If you see dents nicks or a bent casing you can bet that the seal was installed without the proper tool or the tool was damaged Gashes indicate the use
22. dure of SKF technical bulletin No TBF 9301 A Clearance range 0 001 to 0 005 po 0 008 0 004 0 0 004 0 008 0 012 0 016 Increasing life Wheel end setting 26 Hubcap installation procedure Procedure 1 Hub mating surface must be free of dirt burrs and radial score lines 2 Hub mating surface hubcap flange and gasket should not be greased or oiled 3 Always install and re install a hubcap with a new gasket 4 When using a Tamper Proof system with synthetic grease never fill hubcap with grease Bolt on hubcaps e Lockwashers of the split conical or internal toothed design may be used in conjunction with the fastening bolts Do not use flat washers e Thread all bolts loosely then tighten down bolts uniformly in a star pattern per the following recommended torque values TF Zytel Hubcap with embedded metal ring 12 16 lbs ft Stamped Steel Hubcaps 10 14 lbs ft Plastic Hubcap with external metal ring 6 10 Ibs ft Threaded hubcaps e Lightly lubricate the threads of the hubcap and the O ring with the lubricant that is being retained e Install the O ring onto the hubcap e Install the hubcap assembly onto the hub e Using an 8 point 4 13 16 opening x 4 1 4 high socket torque to the following recommended values Lexan 60 70 lbs ft Oil fill Through center fill port e Fill wheel end assembly through centerfill port with the s
23. e two components apart Then set the section Be sure to wear gloves or use a shop rag sleeve assembly aside the top component shown to protect your hands The opened flange above Place it carefully where it is out of the is extremely sharp way but won t be disturbed Internal inspection sealing lip condition Factory Applied Grease Check for grease Locate the primary sealing lip Normal lip flexibility Check the primary sealing and radial dirt lip If the area between them Is lip and dirt lips by pressing downward on them dry something has allowed oil to wash away the with your thumbs sliding them around the entire grease The cause could be excessive end play or circumference The rubber should remain soft a cocked seal Or internal pressure from and flexible in normal use a blocked vent Cracked lips If when you check the primary Flattened bumper lip Scale or rust on the and dirt lips the nitrile feels rough and dry it spindle will prevent the wider Scotseal PlusXL from has probably been subjected to excessive heat sealing properly This creates extra pressure on Loss of lubrication and overtightened bearing the bumper and axial dirt lips The spindle must adjustment are the prime suspects be fully cleaned and all wear rings removed before installing a Scotseal PlusXL 34 Failure analysis Scotseal PlusXL Internal inspection Primary and radial dirt lip wear patterns Good primary lip pattern You shou
24. eranced bearings provides the most reliable bearing end play e Molded pressure ridge on flange bites into setting optimizing wheel end life sealing gasket to ensure leak proof fit e Eliminates the need to verify Zytel is a DuPont material adjustment with a dial indicator SKF rebuild kit for PreSet hub assemblies warranty information SKF believes in the SKF rebuild kits for PreSet so much that we offer a three year extended warranty All the components within the kit are SKF with the exception of the spacer which is the original equipment PreSet spacer by ConMet In each box is a card to fill out and return The policy and registration form will then be forwarded to the mail or e mail address provided All components supplied in the kit must be used in the service of the wheel end This is important because the end play target is a result of the precision tolerancing of the bearing sets and spacer Not using all components could result in a wheel end leak or end play outside of the TMC recommended range of 001 to 005 and thus void the warranty The installation instructions must be followed explicitly The SKF rebuild kit for PreSet warranty policy will provide full details of the warranty program This will come after the warranty card is filled out and returned 15 SKF TF replacement hubcaps Approved by all major OE truck and trailer builders SKF TF hubcaps are compatible with all popular oils and greases Plated
25. he cause of failure and to avoid a similar fate for the replacement seal The cross sectional drawings at right illustrate the critical components of each member of the Scotseal family The captions identify these components as described in the eae following pages Axial For Scotseal PlusXL failures most likely result Dirt Lip from these common errors a e mproper installation 0 D and or D not lubed e Lube contamination as listed above e Spindle not fully prepped e Use of a hammer Note replacing a narrow footed seal like the Scotseal Classic and Scotseal Longlife requires cleaning the spindle along the new area where the wider Scotseal PlusXL will sit Radial D Dirt Lip Below are the key failure modes for Scotseal Classic and Caa Scotseal Longlife These account for the lion s share of Leak Axial i Dirt Lip premature seal failures Paths e Improper installation Wrong or no tool used e Cocked installation e Lubricant contamination Metal flakes Dirt or water Scotseal Classic Mixing of lube types e Improper bearing adjustment Primary e Seal spinning on spindle Sealing Lip Bore Tite Damaged spindle Coating Dirt Lip i Leak e Hub imperfections Paths Bumper e Installed over a wear ring Lip Consult the following pages for examples of Failure Analysis Failure analysis Scotseal Classic Scotseal Longlife Normal scuffing The surface will show some scrape
26. is Scotseal Classic Scotseal Longlife Internal inspection Opening a Scotseal 30 Use pliers or end cutters and work your way all the way around the seal straightening the outer cup flange edges are sharp Internal inspection the major clues Factory Applied Grease Lip grease Every Scotseal comes with grease between the primary and dirt lip If its not there its very likely oil has washed it away Suspects are excessive end play a cocked seal or improper ventilation of the wheel end dirt corrosion or paint plugged vent Remove the inner cup Be sure to wear gloves or use a shop rag to protect your hands the open flange Remove the packing without disturbing the lip surfaces as shown Brittle primary seal lip After cleaning the entire seal use your fingers to curl the primary seal lip back Run your finger completely around the circumference The oil lip should be smooth and pliable If not the seal has overheated lack of lubrication or overtightened bearing adjustment could be the cause Be sure to inspect bearings carefully Broken dirt lip Using the same technique check the dirt lip If its dry and brittle most likely it s been baked It will probably split away from the seal at some point around the circumference Lack of lubrication may have fried the bearings as well 31 Failure analysis Scotseal Classic Scotseal Longlife Internal inspection wear t
27. ld see two parallel lines The primary lip line is slightly wider than the radial lip marking because it s a SKF Waveseal design Primary _ Radial lip wear dirt lip wear pattern pattern Wide wide If both of the tracks formed by the primary and dirt lips are wide chances are the whole wheel assembly is moving in and out at an excessive rate End play like this causes leaks as well as increased tire wear The solution of course is proper bearing adjustment Primary _ Radial lip wear dirt lip wear pattern pattern Wide thin If the primary seal lip line bottom is extra wide while the radial dirt lip line top is light there is excessive pressure on the primary lip For steer and trailer axles that can be a plugged vent on drive axles the tube vent may be locked Primary _ Radial lip wear dirt lip wear pattern pattern Cis Failure analysis Scotseal PlusXL Internal inspection Axial dirt lip and bumper lip wear patterns Axial Dirt Lip Pattern Bumper Lip Wear Pattern Good axial and bumper lip patterns When you Wide shiny If both lines are wide or polished examine the axial face you have two more wear clean then you should suspect that the seal has patterns to learn from About half way up on been compressed This will happen if the face you should see a pencil line track from the I D of the seal isn t lubricated before the axial lip and at the top edge a gently scuffed installation if
28. ler the result of hard particle contamination in the lube 41 Failure analysis for bearings Peeling the tearing away of metal from the race the Discoloration indicates high levels of heat result of the breakdown of lubrication the result of improper lubrication or improper bearing adjustment Installation damage Deformation of the cage the result of improper Cage damage the result of abuse prior to installation or mishandling prior to installation or during installation Cracked cone the result of misapplication Damage to the cup front face the result or cocking the cone at installation of installation damage through use of a hardened driver 42 Failure analysis for bearings Brinelling Brinelling the result of severe impact to the bearing causing one or more of the roller bodies to deform the surface of the race Other damage h Fretting corrosion of the outer surface is often the Light pitting can be caused by electrical arcing result of a worn hub or spindle The probable cause is electrical welding grounded through the shaft Spalling the wearing away of metal from the bearing surface the result of contamination brinelling improper installation improper lubrication or the normal end of bearing life 43 Failure analysis for hubcaps Inspection of lubricant and hub cap The hub cap is constantly exposed to the environment That means hot cold wet dry and salty But so
29. ly a thin layer of oil on the With the fluid being retained may used to tap hub bore that the seal is being pressed into NEVER INSTALL into place DRY is E p 3 Press the seal by hand evenly into the bore A rubber mallet or other soft faced tool may be used to gently tap the seal into place Be sure that the seal is evenly seated and bottomed in the bore As in any seal installation apply an even driving force to avoid cocking the seal or damaging the flange surface 4 Allow seal to set for about 5 minutes prior to installing Press the seal into the hub assembly onto spindle bore evenly by hand Caution Install a new seal if the seal is cocked or damaged during or after installation Installation procedures Scotseal Classic Scotseal Longlife Caution Do not install the Scotseal directly onto the spindle Place the hub wheel assembly against a solid surface or bench at a 45 angle for seal installation This aids in centering the bearing and seal in the hub bore Clean bore of any particles rust or grease 1 Pre lube the inner bearing cone with the lubricant that is being retained and place it into the hub Place the Scotseal Classic or Scotseal Longlife into the hub bore and insert the tool assembly with centering plug into the seal Note Be sure to wear proper eye protection 2 3 Hold the tool handle firmly and straight and drive the seal with firm hammer strokes until the seal is squarely
30. me of It s roughest treatment can come from inside A lack of lube or an over tight bearing adjustment can cook the hub cap and permanently damage It Here are a few of the clues to indicate why a hub cap has failed T K x is EN Distorted bolt hole Bolt hole or flange distortion may Milky window The view window in the hub cap will be the result of excessive bolt torque during installation become nearly opaque white when subject to heat The use of an impact wrench may damage the flange at The heat comes from inside and spells trouble the bolt hole area during assembly Youll want to pull the wheel and check the bearing adjustment check for low lube or a change to an incompatible lubricant Melted window With the hub cap removed inspect the edges of the view window for damage or discoloration If the edge has a rippled look chances are it has started to melt from excessive heat Heat build up could be from running low on lube excessive pre load on bearing or a recent switch to an incompatible lubricant Warped Flange Place hubcap on a flat surface When flange is distorted it will not hold contact all the way around Proper torque specifications may not have been followed Notes Notes Notes SKF is your source for a wide range of products covering various industries From automotive to heavy duty to industrial applications SKF offers a solution to keep your machines operating and your business
31. n of the SKF tapered bearings handle a combination of radial and thrust loads Each tapered bearing set contains a precision matched cup and cone that are specifically designed to maximize bearing performance and life Additionally the SKF part numbers follow industry established numbers allowing for easy look up and identification for specific applications SKF tapered bearing sets e Help the installer do the job right e Ensure longer bearing life e Help prevent premature failure e Increase truck and trailer uptime e Available for all popular applications New from SKF Half stand tapered bearing sets for PreSet hub assemblies SKF also provides specifically toleranced a a half stand tapered bearing sets for the PreSet hub assemblies Re a ring set e Original equipment approved e Precision manufactured to tighter dimensional tolerances specified by ConMet e Superior design and materials reduce friction and provide excellent reliability under heavy loads and misaligned conditions e Global OE supplier The half stand tapered bearings along with an SKF Scotseal PlusXL SKF TF Hubcap and a PreSet spacer are included in the SKF rebuild kit for PreSet Together all the components are manufactured to SKF and ConMet specifications to provide optimum wheel end perfor mance of the PreSet hub assembly 12 13 Extend the life of your PreSet Hub Assembly with the SKF rebuild kit PreSet reliability and
32. nable reliability e Premature seal failure can lead to unexpected wheel end failures that can cause vehicle downtime and damage serious personal injury and even fatalities The TFO wheel end solution Overview Subject Situation problem Just as the equipment needs of long haul commercial fleets vary from those of heavy duty construction fleets so does the matchup of the right seal for the driving environment A good seal can fail prematurely if used in the wrong application Handling wheel bearings correctly at every stage is critical to trouble free operation A bearing that fails unexpectedly can be not just inconvenient but costly and dangerous Hubcaps work through the constant exposure of the environment including hot cold wet dry and road salt conditions Some of the hubcap s roughest treatment comes from inside due to lack of lube or an over tight bearing adjustment causing a cooked hub and permanent damage You can tell a lot about why a bearing or seal has failed prematurely by examining the failed component This guide provides photographs of failed bearings hubcaps and seals along with explanations for the failures Failure analysis Tools for removal and installation of wheel end seals are as critical to seal performance as they are to other tooling issues imagine how wrong it would be to install a new piston with a sledge hammer Related tools such as wheel Fan dollies and end play calibrators
33. pecified grade of oil Wheel hub configurations vary allowing different amounts of oil to be added depending on design Allow for the oil to seep through the outer bearing and fill the hub cavity Continue to add oil until the oil reaches the oil level fill line as indicated on the hubcap e Install center fill hubcap plug Through side fill port e Fill wheel end assembly through side fill port with the specified grade of oil Wheel hub configurations vary allowing different amounts of oil to be added depending on design Allow for the oil to seep through the outer bearing and fill the hub cavity During this fill operation DO NOT ALLOW THE OIL TO GO ABOVE THE CENTERLINE OR WEEP HOLE This may result in a weeping condition that may be perceived as a leaking hubcap Continue to add oil until the oil reaches the oil level line as indicated on the hubcap e Install side fill hubcap plug per the following recommended torque values 3 8 18 NPT Pipe Plug 100 140 lbs in 3 4 16 UNF Zytel Side Fill Plug 15 25 lbs in Clean up any overspills that would give the appearance of a leaky hubcap Grease fill See TMC RP631 Recommendations for Wheel End Lubrication and the vehicle manufacturer s recommendation for proper fill procedure 2d Failure analysis An important step in achieving Wheel End TFO Failure analysis of prematurely failed seals is one Scotseal PlusXL of the best means to discover t
34. per rollers and a metal or polymer cage This cage contains the rollers and an inner ring which is the interface surface with the shaft or spindle mating surface Since there are many moving parts on the cone you should slowly rotate the cone assembly for proper inspection of all surfaces of the components Make a careful inspection and look for the following e Corrosion Inner ring e Metallic debris e Pitting e Metallic flakes e Other signs of damage or wear E dA Roller end fracture due to heavy stress peaks caused by slackness of too loose bearing adjustment Scoring indicates contamination by dirt grit or metallic particles Roller end wear caused by over tightening lubrication degradation or lack of lubricant Coloration indicates an overheated bearing from straw brown to deep purple Causes are lack of lubricant misadjustment or excessive loading Roller end cracks indicate excessive loading or excessive misalignment Wear marks in bands are due to foreign particles causing mild abrasive wear 38 Inspection Bearing cage and inner ring The bearing cage is made of either pressed steel or polymer and is therefore subject to various forms of damage These cages are deformed due to rough handling dropping on the floor being thrown in a box with other hard components etc or poor installation with shock loads caused by hammering during removal or install
35. racks Primary Lip Wear Pattern Dirt Lip Wear Pattern Contamina tion Being Excluded Good pattern What you will see in a good Wide wide If both lines are wider than pencil Scotseal are the two parallel lines that look lines it means that the primary lip and dirt lip like they ve been drawn with a sharp pencil have been allowed to move in and out on the Theyre approximately the same size and equidistant outer cup The cause of this is excessive endplay from the edge all the way around the inside indicating that the bearing endplay is greater of the outer cup than the recommended range of 001 and 005 Metal shavings in lip area Before cleaning Cocked seal inner markings Holding the seal inspect the seal area for traces of metal the outer cup just below eye level and flat particles A magnet can attract metal particles Sharp like a bowl rotate your wrist through 360 edges of metal may have cut the seal primary lip If the seal has run cocked the two lines will causing the seal to leak be parallel to each other but they appear to move closer and then farther from the outer cup flange Failure Analysis Scotseal PlusXL External inspection checking the beads 32 Normal exterior The tough nitrile covering on the Scotseal PlusXL doesn t supply clues as readily as Bore Tite does But it can still reveal problems and lead to corrective measures There should be lubrication in each of the O D I
36. rm in very harsh conditions The new Scotseal PlusXL with the unique hand installable design includes a wide footprint ensuring stability on the shaft Worn hubs and spindles are not a problem for the Scotseal PlusXL Scotseal Longlife Building upon the success of the original Scotseal design SKF engineers had a great start in their development of a new extended life seal Computer aided design CAD of lip geometry and the addition of an axial dirt excluder lip was combined with a newly formulated material to produce Scotseal Longlife a premium performance seal with the characteristics required by many of today s demanding heavy duty environments Scotseal Classic The original Self Contained Oil Type Seal Scotseal Classic became the trucking industry standard and the best value for more than 30 years With literally trillions of road miles to its credit Scotseal Classic has proven to be a solid choice for dependable long lasting service Time and time again field studies show that when properly installed using SKF tools and procedures Scotseal Classic is a reliable performer for meeting the sealing requirements between brake maintenance intervals SKF Scotseal descriptions and fitting information SKF Scotseal PlusXL is a rubber unitized one piece design The Scotseal PlusXL consists of four sealing lips a spring loaded primary sealing lip with patented Waveseal design that is factory pre lubed
37. seal lip Lube leakage Inspection of lubricant Inspection of grease or oil can provide a clue to other problems Remove a sample from the wheel end and check for the following e Presence of contaminants e Burnt aroma e Presence of water Grease and oil lubricants has pre determined that the wheel end assembly is to be lubricated by grease or oil The importance of following the manufacturer s specifications cannot be over emphasized never change or mix grease and oil in the same assembly Always use lubricants as recommended by the manufacturer BRAKES The truck or trailer manufacturer Higher temperatures Lube deterioration BEARINGS Hot running causes physical damage Prior to re installing bearings always check for the proper lubricant Wheel end lubricants are formulated to match the requirements of the truck and bearing manufacturer e Always use specified lubricant e Do not mix lubricants e Chemical interaction between lubricants and seal materials can damage the seal e Whenever possible use a grease packer Grease lubricated wheel ends For proper lubrication the grease must be packed into the cavities between the rollers and cage of the bearing cone A mechanical grease packer is recommended in order to improve on the common procedure of filling the grease by hand Also apply a light film of grease to the axle spindle for corrosion protection T
38. tact between the seal O D and the hub bore surface as well as a metal to metal contact between the packing I D and the spindle See Figure 3 Scotseal PlusXL HUB BORE OD Beads Spring AIR SIDE gt Bumper Lip OIL amp BEARING lt SIDE Axial Dirt Lip Radial Dirt Lip Primary Sealing Lip fi ID Beads SHAFT Figure 1 Scotseal Longlife HUB BORE AIR SIDE gt Primary Sealing Lip Radial Dirt Lip Bore Tite Coating OIL amp BEARING lt SIDE Axial Dirt Lip Spring Packing SHAFT Figure 2 Scotseal Classic HUB BORE Primary Sealing Lip Bore Tite Coating OIL amp Dirt Lip _ Bumper BEARING Lip lt SIDE Spring AIR Packing ___ SIDE gt SHAFT Figure 3 1 4 99 TFO Good practice tips To prevent wheel end leakage problems be a good detective look for clues Our experience has shown that there are many causes of wheel end leakage beyond the oil seal If you look you will find that leaking wheel ends leave clues pointing to which component or components are the culprits Follow the guidelines of the checklist below as you service the wheel end You may find that just changing the seal may not be your permanent solution Inspect for indications of leakage Under vehicle inspection e Smells burnt indicates overheating e Oil present past the seal Check condition of fastening system e Oil contaminated hub
39. the sleeve wasn t sealed fully pattern from the bumper lip on the spindle or if the bearing adjustment is too tight Hard Contact Uneven patterns If the bumper lip path is shiny in one sector but dull in the opposite sector you can be sure the seal was cocked The bumper lip is making hard contact through half the revolution and almost no contact through the rest of it No Contact Gio Inspection Bearing cup The most commonly damaged portion of the bearing cup is the tapered raceway surface inside the cup Make a careful inspection and look for the following e Evidence of corrosion e Metallic debris e Pitting of the surface e Metallic flakes e Any other signs of damage or foreign matter Severe sliding wear due to Etching of metal generally presence of hard abrasives indicates water contamination allowing oxidation to attack the surface Dent across the race indicates Cup shows considerable Heavy grooving by large a sharp high impact corrosion This will develop hard particles in the lubricant in spalling Dings and dents in the bearing Typical surface appearance Surface appearance caused by surfaces indicates a drift was with repeated effects of vibra electrical arcing during welding used during Installation tion called false brinelling oT Inspection Bearing cone Rollers The cone of the bearing is a composite assembly consisting Shaft of ta
40. tion Disassembly Re Assembly 17 26 e Seals e Bearings e Hubcaps Failure ANALYSIS ccs 27 43 e Seals e Bearings e Hubcaps All contents copyright 2009 SKF Group TFO and Trouble Free Operation are registered trademarks of SKF Group Why a systems approach Improper procedures during the removal disassembly and replacement of wheel end components Personal lack of cleanliness in handling components allows particles and dirt to cause bearing and seal damage Removal of bearings and seals with incorrect tools causes damage to spindle or hub which can be undetected and lead to future problems Lack of understanding the important role of lubricants can lead to future problems Use of improper or damaged installation tools can damage new components Lack of knowledge about critical end play i adjustment can cause premature or even catastrophic wheel end failure Improper mounting procedures can damage new components Lack of knowledge concerning bearing and seal failures prevents corrective action Lack of training or unskilled personnel can lead to any of these causes of failure Warranties under the TFO program In addition to helping your fleet reduce wheel end maintenance and its associated costs you can also benefit from special extended warranties on selected products when certain requirements are met The following warranties are provided for the SKF line of Scotseals pur
41. ub must be replaced WARNING Never work under a unit supported by only a jack Always support the vehicle with stands Block the wheels and make sure the unit will not roll before releasing brakes Always wear eye protection 19 The SRT 1 seal removal tool U S Patent No 5 617 621 The SKF SRT 1 Seal Removal Tool is recommended for removal of most tractor truck dolly or trailer wheel seals With the wheel hub assembly removed from the axle simply insert the hook tip of the tool between the seal and bearing The unique design of the tool allows you to use leverage to easily and safely remove the seal without damaging the spindle Remember performing seal failure analysis will ensure improved performance See pages 27 35 for seal failure analysis information WARNING Do not add a handle extension to the tool This tool is to be used for seal removal only Simple design rugged construction and ergonomic features increase your productivity and eliminate costly bearing damage e Saves time no more laborious prying against e Rubber grip for security in handling bearings or driving out seals e Heavy duty construction for long life and e Saves bearings tool grabs seal only and bearings dependability go undamaged e Works with steer drive and trailer wheel seals e Easy to use wedges and long handle provide e Seal is removed intact allowing for proper seal exceptional leverage inspe
42. uld pull the spacer and rebuild your PreSet wheel end with individual components from several suppliers there are some compelling reasons to install the SKF rebuild kit for PreSet Reduce fleet downtime Unlike off the shelf components all of the kit s parts are manufactured to SKF s and ConMet s specifications ultimately reducing downtime and lowering operating costs Simpler installation One procedure regardless of axle type eliminating potential failures due to error no need for complicated torquing and use of a dial indicator Extended 3 year warranty In addition by installing the ConMet approved SKF rebuild kit for PreSet you will receive an extended 3 year warranty on these SKF wheel end components Longer service life Because the kit meets the exact specifications of the original PreSet system components you can expect the same kind of reliability and performance from your rebuilt wheel end Precision machined SKF TF hubcap PreSet spacer e Lightweight DuPont Zytel material is stronger than aluminum resisting impact e Manufactured of high strength alloy to i damage chemicals UV and ozone precise tolerances e Embedded solid aluminum ring distributes e Eliminates need for manual end play l an even leak proof load against the hub adjustment e Cloud free window is fusion bonded to body e Proprietary machined bearing spacer along no screws to shake loose and no leaking with the SKF specifically tol
43. ypical mechanical grease packer E Helpful hints e Stay organized a messy shop is e Do not use chisels impact wrenches and torches dangerous and inefficient e Do not use hammers directly on seals or bearings e Keep loose components together e t is important to not mix wheel end components bearings are mates that wear together This includes new bearings Do not use compressed air After cleaning dry with a clean paper towel or a clean rag Air jets cause small abrasive particles to become jammed in between the bearing surfaces 18 Inspection of the spindle and hub 1 Inspect the spindle and spindle threads for damage and remove light frett Also check for the following e Spalling e Corrosion pits e Discoloration from overheating e Punch marks chisel marks e Weld beads e Upset metal Note Damaged threads can be repaired using a pitch thread file or die nut 2 Inspect the fastener Locknut Bearing adjustment nut Washer The use of these spindle end components varies by truck or trailer manufacturer Look for chisel marks or other deformation as a sign of improper installation or an attempt to make temporary repairs 3 Inspect the inside and the outside of the hub Look for the following e Broken fasteners bolts e Cracks in the housing e Damage to the hub and bore Note If the bearing cup is loose in the hub this indicates a serious condition and the h
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