Series 40 M46 Variable Pump Control Spool
Contents
1. Service Kit Instructions Series 40 M46 Neutral start switch spool replacement procedure cee Pars OVERVIEW The rotary control spool in the M46 series variable pump wears with use possibly causing controllability problems in certain applications A new induction hardened control spool has been created that limits this wear This procedure details the steps to replaced this control spool in M46 models that have the Neutral Start Switch NSS feature This procedure requires a spool replacement kit Sauer Danfoss part number 4510456 reference Sauer Danfoss publication BLN 9939 M46 Service Manual PRELIMINARY NOTES Thoroughly clean the pump control NSS area of dirt and water The introduction of foreign material dirt sand or water reduces the life and controllability of hydraulic A Warning systems Make sure prime mover engine is OFF There are two pump control adjustments affected by this procedure pump neutral and the neutral start switch function Follow the adjustment procedure for pump control neutral and NSS function as outlined in the Final Adjustments section of this bulletin This procedure may be preformed with the pump in the vehicle If there is less than 5 inches of clearance directly above the pump control assembly the pump must be removed from the vehicle If possible the two pump mounting bolts may be removed and the pump rotated to gain access If equipped shut the isolation valve in the pump suction line2. from the reservoir Remember to reopen it before restarting the engine Ensure all parts of kit 4510456 are available and the new spool cam assembly is properly assembled REMOVAL OF SPOOL 1 Disconnect the NSS switch 1236 at _ O 3 8 in the quick disconnect A 1213 O 1 2 in Removal ofthe pump 2 With a 1 2 inch wrench remove the ap 1257___ 1235 neutral adjustment bracket control handle locknut 1213 and r is not necessary during star washer 1235 this procedure However 3 Witha3 8 inch wrench remove the as a precaution mark the two cover screws 1256 position of the bracket 4 Remove the NSS spool assembly from the pump 5 With a hammer tap the spool cam assembly 1249 from the NSS housing Hold the control handle spring and neutral adjustment bracket in place during replacement of spool 6 Remove the expansion plug 1257 by pressing it out from the inside Danfoss 2013 BLN 10249 Rev AA September 2013 1 INSTALL THE NEW SPOOL FINAL ADJUSTMENTS W Warning Unintended vehicle movement hazard Protect yourself and bystanders from serious injury or death Raise and secure the drive wheels off the ground or securely chock the wheels Do not depend on the parking brake alone for protection Danfoss 2013 Donfs 1 Apply grease inside the NSS housing 1256 23 8 in 2 6 8 N m thoroughly coating the ca
3. m face 3 8 11 Ibf ft 2 Lubricate and insert the new spool 1213 Q 1 2 in assembly into the NSS housing 1257 A 2 7 9 Nem 1251 12 23 Ibf ft 3 Install the star washer and finger tighten the locknut onto the new spool 4 Set the neutral cam with the neutral start switch in the detent of the cam 5 Set the new NSS housing gasket 1255 in place on the mounting plate 6 Insert the control spool NSS assembly on the pump 7 Attach the cover with two screws 1256 torque to 6 8 Nem 8 11 Ibf ft 8 Torque the spool locknut 1213 to 7 9 Nem 10 12 Ibf ft Check for free spool movement and spring return function It may be necessary loosen and retorque the screws to prevent binding of the control handle and spool Do not tighten the neutral start adjustment set screw B through the expansion plug hole until pump neutral is set see final adjustments If the control neutral is adjusted with the NSS screw tightened the vehicle engine may not start If the pump neutral adjustment bracket was not removed during this procedure the pump will be in or very near the neutral set point with the new spool installed However do not assume the neutral set point is correct Always check for control neutral either with servo pressure gauges or with the wheels up method before placing the vehicle back in service See M46 Service Manual BLN 9939 for more information 1 Install 0 300 psi gauges in bo
4. th servo test ports 2 Loosen the washer head screw to allow the neutral adjustment bracket to move but not freely 3 Start the prime mover and slowly accelerate to normal operating speed 4 Slowly rotate the neutral adjustment bracket until one of the servo gauges begins to increase pressure Mark the position 5 Slowly move the bracket in the opposite direction until the other gauge begins to increase pressure Mark the position 6 Rotate the bracket to a position at the midpoint between the marks and hold securely in place while torquing the washer head screw to 11 15 N m 8 11 Ibf ft 7 Stop the prime mover remove the gauge and install the gauge port plugs 8 Reinstall and adjust the control linkage if necessary BLN 10249 Rev AA September 2013 2
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