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Lotus Service Notes Section CI

1. General Description Geometry amp Adjustments Anti Roll Bar Suspension Disassembly Assembly Front Wheel Bearings FRONT SUSPENSION SECTION Cl Sub Section Cl 1 Cl 2 CI 3 Cl 4 CI 5 Page 3 3 10 M PAC 1 pees _ amp Lotus Service Notes Section Cl GENERAL LAYOUT Spring damper unit Top wishbone Steering tie rod Upper swivel joint Track rod end Steering Anti roll bar mounting Anti roll bar Bottom wishbone Hub carrier Wheel hub Lower steering swivel joint Page 2 Cl 1 GENERAL DESCRIPTION The fully independent front suspension comprises on each side of the car upper and lower wishbones a concentric coil spring telescopic damper unit and a tubular anti roll bar A forged steel hub carrier provides a mounting for a the hub bearing unit to which the road wheel is attached via four spline socket bolts The upper and lower A frame wishbones are fabricated from steel tube the upper wishone braced by sheet steel gussets at its apex and the lower wishbone braced by a tubular strut at its base The inboard ends of both wishbones use replaceable bonded rubber pivot bushes to provide maintenance free articulation with a specification providing accurate and responsive dynamic characteristics The outer ends of both wishbones incorporate housings into which the upper and lower steering swivel ball joints are pressed The upper ball pin is secured to the forged
2. and is linked to the outboard ends of each lower front wishbone via short ball jointed links On cars fitted with the motorsport anti roll bar the ends of th ed bar are equipped with 5 holes to allow some a ustment of roll stiffness to diof the chassis Standard be made Standard settin Sg h e S e an roll o tke fron isp isa tainey by Sackets Washers welded Two types of moun Elise models use rubbery to the bar bear against the inner sides of the bushes to provide lateral location of the bar Castrol LMX rubber grease or equivalent should be used when fitting the rubber bushes onto the anti roll bar For the anti roll bars used with roadsport suspension and on Exige the bar is secured by two Nylon clamps fixed to the chassis via the front lower wishone inboard front pivot bolt with a top hat section steel Spacer preventing the clamp from being crushed These hard type mountings provide optimum steering re sponse but will transmit more noise and require periodic lubrication with MoS grease at 3 000 mile 5 000 km intervals Note that the two types of mounting require differently shaped bars with that for the rubber mounts being positioned higher on the chassis than the hard mount version Anti Roll Bar Mounting Rubber Spacer plate Rubber mounting Clamp bracket Wishbone pivot bolt Spacer tube Anti Roll Bar Mounting Nylon A f L Ck M LLZ ET ZE E
3. angle changes with suspension travel becoming more negative on bump and should be measured only at the specified ride height Incorrect camber can result in handling deficiencies and excessive tyre wear Camber angle Vertical Wheel centreline Camber adjustment is effected by adding or deleting shim plates between the steering arm to which the upper steering swivel joint is fixed and the hub carrier Camber adjustment shimplate Steering arm Hub carrier Shimplates are available in 1mm and 3mm thicknesses Reducing the shim pack thickness will increase negative camber Adding shims will reduce negative camber A 1mm shim plate will alter camber by approximately 0 25 Apply Permabond A130 A912E7033 to the two steering arm fixing bolts and tighten to 45 Nm Castor Adjustment Castor is the angle from vertical of the steering axis of the wheel when viewed from the side Its primary purpose is to provide a natural straight running tendency of the steered wheels with forward vehicle motion Castor angles have a complex interaction with other steering geometries and if unbalanced or outside of speci fication can result in various stability and handling deficiencies 0 FRONT Top amp bottom steering swivels Castor angle The wishbone pivot bushes are bonded rubber type with a plastic flanged outer sleeve a plain steel in ner sleeve and a plastic interleaf sleeve within the rubber bush to control
4. s Sm GY ia 1G 60 m m A mm Page 12 EE ee
5. spring is to be removed from the damper unit With the car on a wheel free lift and with the front wheels removed 1 Remove the wheelarch liner s as appropriate 2 Remove the two bolts securing the brake caliper to the hub carrier release the flexible hose from the top wishbone and support the caliper aside without straining the brake hose Release the single countersunk screw and remove the brake disc 3 Remove the nut securing the track rod end into the steering arm and use a ball joint splitter to separate the rod end from the arm 4 Remove the nut securing the top swivel joint to the steering arm and use a ball joint splitter to separate the joint from the arm Remove the two M10 fixing bolts and remove the steering arm from the hub carrier taking care not to misplace the camber adjustment shim plates 5 Remove the nut securing the lower swivel joint to the hub carrier and use a ball joint splitter to separate the ball pin from the carrier 6 Remove the bolts securing the spring damper unit to the lower wishbone and chassis anchor bracket and withdraw the unit noting the spacer washers fitted at the top end 7 Disconnect the anti roll bar drop link from the lower wishbone and remove the lower wishbone front pivot bolt 8 Remove the lower wishbone rear pivot bolt from within the cabin footwell and withdraw the wishbone 9 Before removing the two pivot bolts for the top wishbone take careful note of the distribution o
6. the flexing characteristic The top wishbone rear bush identified by a blue paint mark has no interleaf sleeve The top wishbone pivots are sandwiched between the walls of transverse chassis box sections the pick up points in which are reinforced either with machined inserts or in the case of the foremost position a thick alloy plate each being bonded to the chassis with epoxy adhesive Spacer washers are fitted ahead of and behind each of the top wishbone pivot bushes to allow the wishbone to be displaced forwards or backwards with an associated change of castor angle A rubber faced snubber washer fitted against the rear face of the top wishbone front bush prevents metal to metal contact under extreme braking forces The spacer washers may be re distributed between the front and rear of each pivot bush but the snubber washer position and the total shim pack thickness of 4 x 1 5mm at each pivot inc the 1 5mm snubber washer must remain unchanged Top Wishbone Inboard Fixing FRONT Front leg Rear leg 1 5mm shim 1 5mm shim washers washers Flanged plastic outer sleeve ca al Plastic Inner steel Bonded Bonded interleaf sleeve plate Rubber faced inserts EZ snubber washer Page 6 Notes Shim distribution at the front bush of either wishbone must be copied at the rear bush of that wishbone Transferring a 1 5mm shim washer from ahead of to behind the pivot bushes will reduce castor by ap proximately 0
7. 4 Transferring a 1 5mm shim washer from behind to ahead of the pivot bushes will increase castor by approximately 0 4 Ensure that the load spreading washers are correctly located beneath the bolt heads and nuts as shown in the drawings Ensure that the pivot bolts are tightened only with the vehicle at ride height Torque to 45 Nm Cl 3 ANTI ROLL BAR A tubular steel anti roll bar is mounted in pivot bushes onto the front face of the chassis and is linked to the outboard ends of each lower front wishbone via short ball jointed links The chassis mounted pivots use rubber bushes for noise isolation and are retained by alloy clamp brackets Washers welded to the bar bear against the inner sides of the bushes to provide lateral location of the bar Castrol LMX rubber grease or equivalent should be used when fitting the rubber bushes onto the anti roll bar To remove the bar the alloy bracket at each side connecting the bottom of the crash structure to the chassis must be first be removed by drilling out the rivets Anti Roll Bar Mounting Rubber Spacer plate Rubber mounting S Clamp bracket Fixing bolts Anti Roll Bar Drop Link Lower wishbone Anti roll bar drop link Anti roll bar Cl 4 SUSPENSION DISASSEMBLY ASSEMBLY The suspension may be disassembled without the use of any special tools other than a Torx socket for the hub bearing carrier bolts and a spring compressor required only if the
8. ate a wheel speed sensor in the bearing unit with a flying lead terminating in an electrical connector plug secured by a camber shim plate bracket If there is found to be any discernible free play in the hub bearing or any roughness or tight spots can be felt or any signs of lubricant expulsion are evident the hub assembly should be replaced there is no provi sion for adjustment To Replace Hub Bearing Assembly 1 With the wheel removed release the two fixing bolts and remove the brake caliper from the hub carrier Support clear of the brake disc without straining the flexible hose Release the single countersunk screw and withdraw the brake disc from the hub 2 Using a Torx socket release the three bolts securing the hub bearing unit to the hub carrier 3 Fit the new hub bearing unit to the hub carrier and retain with the three Torx bolts Torque tighten to 90 Nm 4 Refit the brake disc and caliper using Permabond A130 A912E7033 to the threads of the caliper fixing bolts and torque tightening to 45 Nm Pump the brake pedal to reposition the pads before driving the Car le Steering arm Hub carrier 7 Y A Ls ZZ at VL LLL AZ oo fe OT on VAR z7 7 Per A Hub to carrier fixing bolt KA ARSA SX NKS Swaged bearing retention d WF Double row ball bearing SO Page 11 mmm Cl 3 ANTI ROLL BAR A tubular steel anti roll bar is mounted in pivot bushes onto the front face of the chassis
9. ated by a square section circlip on the damper body Standard Elise Use centre of 3 grooves for mid laden ride height of 130mm USA Elise Use lower of 3 grooves for mid laden ride height of 135mm Elise with Roadsports suspension package and non USA Exige Use the upper of 2 grooves for mid laden ride height of 130mm 14 To remove the hub bearing unit from the hub carrier release the three Torx head bolts and withdraw the complete unit The hub unit is not serviceable and is replaced complete if faulty Reassembly Re assemble the suspension in reverse order to disassembly with the following notes Take care to assemble each pivot bolt with the correct washers snubbers spacers as shown in the dia grams Smear the shank of each pivot bolt with PBC grease but do not allow contamination of the threads Take care to refit the original camber adjustment shimpack and distribute the castor shims as noted on removal Top ball joint plinth fixing bolts The bolts securing the steering arm top ball joint plinth to the hub carrier were upgraded in March 04 at VIN serial number 1537 approx in order to commonise with motorsport applications Earlier type 8 8 grade bolts should be tightened to 45 Nm Later 10 9 grade bolts to 68 Nm The bolt grade is stamped around the head of the bolt The thread of both bolt types should first be treated with Permabond A130 A912E7033V After re fitting a standard anti roll bar ensure that t
10. ce 0 1 to 0 3 Max side side 0 2 Castor optimum 3 8 tolerance 3 5 to 4 1 max side side 0 35 Alignment optimum Zero tolerance 0 5 mm toe out to 0 7 mm toe in overall Steering axis inclination Roadsport Elise Exige 0 07 toe out to 0 10 toe in overall 12 nominal Mid laden ride height reference height for geometry check front 130mm below front end of chassis siderail rear 130mm below rear end of chassis siderail Camber optimum 0 3 tolerance 0 1 to 0 5 max side side 0 2 Castor optimum 3 8 tolerance 3 5 to 4 1 max side side 0 35 Alignment optimum Zero tolerance 0 5 mm toe out to 0 5 mm toe in overall Steering axis inclination 0 07 toe out to 0 07 toe in overall 12 nominal Alignment Wheel alignment refers to the parallelism of the wheels when viewed from above and is crucial to vehicle stability handling and tyre wear Difference between rim measurements overall toe out Alignment is measured either by the angle a wheel makes with the vehicle centre line or the difference in dimension between the wheel rim to wheel rim measurement at the front and rear of the wheel at hub centre height The wheels are said to toe in when the wheel paths converge ahead of the vehicle and toe out when they diverge Wheel alignment is designed to vary with both steering angle Ackerman and suspension travel bump steer and shou
11. f castor adjustment washers Move the steering rack to full lock to provide clearance for the withdrawal of the wishbone rear pivot bolt Withdraw the wishbone 10 The wishbone pivot bushes comprise a rubber bush bonded to a steel inner sleeve and a flanged plastic outer sleeve The bushes may be pressed out of the wishbone eyes and new bushes fitted using suit able press tool dollies Smear the outer surface of the new bush with IPC P 80 rubber lubricant emulsion A082C6042V to ease fitment and assemble as follows Top wishbone insert from the outside of both pivot eyes from front of front eye and rear of rear eye Lower wishbone insert from the inside of both pivot eyes from rear of front eye and front of rear eye Note that all top wishbone pivot bushes are common with the exception of the top wishbone rear pivot which contains no interleaf sleeve and is identified by a blue paint mark 11 Top and bottom swivel joints are identical and may be replaced if necessary using a suitable press 12 If the anti roll bar is to be removed remove the front alloy undertray and by drilling out the rivets the small alloy closing panel at each side of the crash structure below the anti roll bar Release the a r bar clamps and drop links and withdraw the bar 13 The road spring may be removed from the damper using a suitable spring compressor to allow the spring lower slotted seat to be withdrawn Note that spring upper seat is loc
12. fied torque is attained without the fixing being disturbed moving take no further action If the bolt moves the locking action of the thread adhesive will have been compromised Remove the M OGC pees bolt completely clean off all old adhesive using a wire brush and acetone and apply new adhesive as specified Refit the bolt and tighten to the specified torque If for any reason a bolt is found to have become loose and the car has been operated for any period in this condition the bolt should be renewed as a standard precaution and related components carefully inspected for hole ovality or wear Torque Settings Nm Upper and lower wishbone pivot bolts 45 Upper swivel joint to steering arm 55 Lower swivel joint to plinth 55 Steering arm to hub carrier 8 8 grade 45 10 9 grade 68 Track rod end to steering arm 30 Damper to lower wishbone 45 Damper to top anchor bracket 45 Damper anchor bracket to chassis 25 Hub bearing unit to hub carrier 90 Brake caliper to hub carrier 45 Anti roll bar rubber bush mounting clamps 25 Anti roll bar drop links 45 CI 5 FRONT WHEEL BEARINGS The sealed front wheel bearings are contained in a steel housing secured to the hub carrier with three Torx bolts The double row angular contact ball bearing is retained in the outer housing and also onto the hub spigot by a shoulder and a peening operation and is inseparable for service Note that all four hub as semblies are common and incorpor
13. he crash structure closing panels are re rivetted Lubricate the rubber type anti roll bar mountings with rubber grease and the Nylon type with Mos grease Apply Permabond A130 A912E7033V to the threads of the steering arm bolts Lubricate the ends of the damper top eye bush with rubber grease Press the brake pedal to reposition the pads before driving the car If the car suffers a suspension impact sufficient to damage a wheel rim careful attention should be paid to all related suspension components Such forces can cause stretching of the lower ball pin and consequent fixing nut torque loss As a safety precaution it is recommended that in all such cases the lower ball joint and the two bolts securing the upper ball joint plinth to the hub carrier are renewed The Service Schedule specifies that the security of the front and rear suspension is checked at each service For cars used on race tracks or in similar conditions suspension components and torque checks should be carried out between sessions This operation requires that all the principal suspension pivot bolts are torque checked noting the following points Where a bolt is tapped into a housing or weldnut and relies on a thread locking compound for security it is important to appreciate that if the bolt is disturbed the locking compound must be re applied The following procedure should be adopted for all such fixings Check the torque of the fixing If the speci
14. ld be measured only straight ahead at the specified ride height Front wheel alignment is adjusted be screwing the track rods into or out of the track rod outer end ball joints In order to preserve the required bump steer characteristic and steering symmetry the effective length of each track rod must remain equal adjust each track rod by a similar amount Steering rack gaiter Track rod end flats Track rod end Steering arm Steering track rod flats Track rod end locknut Hold the track rod end using the flats provided and slacken the locknut Repeat for the opposite side Turn each track rod a similar amount As a guide turning both track rods by one quarter of a turn will alter overall toe out by approx 2 0 mm When adjustment is correct hold each track rod end and tighten the locknuts to 80 82 Nm 58 60 Ibf ft When slackening or tightening the track rod end locknuts it is important that the torque reaction is resisted using the track rod end flats and that the ball joint itself is not allowed to be stressed Camber Adjustment Camber is the angle from vertical of the wheel when viewed from the front and is said to be negative when the wheel leans inwards at the top positive when leaning outwards The primary purpose of camber is to achieve the maximum efficiency of the tyre under cornering loads and body roll with the specification closely allied to a particular wheel tyre combination The camber
15. steel rearward facing steering arm itself fixed to the hub carrier by two M10 bolts The ball pin of the lower swivel joint is secured directly into a tapered hole in the bottom of the forged steel hub carrier The Bilstein spring damper unit acts between the outer end of the lower wishbone and the chassis and is fitted with the damper rod lowermost in order to minimise unsprung weight A forward mounted tubular steel anti roll bar is supported in chassis mounted rubber pivot bushes and is operated via short ball jointed drop links from the lower wishbones Cl 2 GEOMETRY amp ADJUSTMENTS Provision is made for the adjustment of wheel alignment camber and castor Under normal service con ditions no periodic scheduled check of the geometry is necessary although a front wheel alignment check is recommended when the front tyres are replaced A full geometry check is required only after front suspension repair or if excessive tyre wear is evident or if steering difficulties are encountered Before any measurements or adjustments are made it is essential first to set the vehicle to its mid laden ride height approximating to driver and passenger and a half tank of fuel This will require the vehicle to be ballasted or tied down Standard Elise Mid laden ride height reference height for geometry check front 130 mm below front end of chassis siderail rear 130 mm below rear end of chassis siderail Camber optimum 0 1 toleran

Lotus Service Notes Section CI

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