Installing Rear Drive Axle With Air Operated Differential Lock
When we started working on this 2008 school bus it was supposed to be a basic brake job on the rear axle. As it turned out the passenger side wheel seal was leaking so the hub assembly needed to be removed. The video shows you how we had to reinstall the drive axle.
The reason I posted it here is to show how we figured out how to align the diff lock shift collar to fit the drive axle back in to the housing. When the axle was removed to replace the wheel seal the shift collar dropped down and flopped over.
This caused some anxiety because this had never happened before. This is the first bus with the air shift differential lock that we removed a drive axle on. It was a complete surprise that this shifter would be so difficult to line up. Below is a method we used that worked great for us.
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To fit the axle splines into the shift collar we turned the dash ‘Differential Lock’ button ‘ON’ while the shift collar was held in the center position with a broom stick. It sounds strange but it worked. The axle had two sets of splines one for the differential side gear and the other for the diff lock collar. The alarm you heard in the video is normal when the spring brakes are NOT applied with the ignition key on.
Procedure For Wheel Hub Removal and Installation
If you are not familiar with this procedure it involves removing the axle retaining nuts and pounding on the end of it so it pops out of the housing. Next the outer and inner wheel bearing lock nuts are loosened off and removed to allow removal of the hub. NOTE: Hub removal was necessary so we could change a leaking wheel seal.
For installation the bearings are prelubed, the hub filled with gear oil and the inner nut installed to adjust the wheel bearings. The inner nut must be tightened as tight as possible then backed off (this seats the bearings).
For the rear drive axle the preload on the bearings is 50 foot pounds. The outer lock nut is then torqued to 250 foot pounds. These adjustment specs have worked well for us without any problems. The front steering axle wheel bearings adjustment is set to 25 foot pounds. With the same 250 foot pound Torque on the lock nut.
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