differential bearing preload sprinter 4x4 front axle
01-25-2019, 07:26 AM
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1988 507d, 1999 312d 4x4, 2001 311cdi 4x4
differential bearing preload sprinter 4x4 front axle
Hi Has anybody got an up to date copy of WIS they are willing to check for me (or has anyone rebuilt the front drive on a 2001 sprinter 311cdi 4x4.)...
WIS document AR33.30-D-8610-O2A has info on bearing preload...... the problem I am having is
the differential tube has a bearing on each end of the tube the differential is mounted in.... The mercedes WIS (2014 copy) I have says to assemble the unit with no shims behind bearing, measure end float with dial gauge then do maths by subtracting 0.15mm to arrive at shim thickness required,....
This is straight forward and if done correctly will set up the bearings with 0.15mm end float.
I have done this and the shaft rotates freely with very little drag BUT
the next instruction says to use a torque gauge to measure the resistance to rotation of the differential tube and that it should be between 3 to 5 NM
If the shims etc. are fitted as per first part of instruction the rotational torque is zero in effect.
If 0.15mm IS ADDED to endfloat measurement RATHER THAN SUBTRACTED with no shims then the bearings will be preloaded and the torque may be close to 3 to 5NM
With a 0.05mm pinch on the bearings I am getting a torque figure on the shaft of about 1.0 NM ..
the outer casing the differential tube runs in is aluminium the differential tube is steel therefore different rates of expansion... do i preload the bearings ? If so do I preload the bearings by enough to create torque of 3 to 5NM which seems a lot?
thanks for any help mark
WIS document AR33.30-D-8610-O2A has info on bearing preload...... the problem I am having is
the differential tube has a bearing on each end of the tube the differential is mounted in.... The mercedes WIS (2014 copy) I have says to assemble the unit with no shims behind bearing, measure end float with dial gauge then do maths by subtracting 0.15mm to arrive at shim thickness required,....
This is straight forward and if done correctly will set up the bearings with 0.15mm end float.
I have done this and the shaft rotates freely with very little drag BUT
the next instruction says to use a torque gauge to measure the resistance to rotation of the differential tube and that it should be between 3 to 5 NM
If the shims etc. are fitted as per first part of instruction the rotational torque is zero in effect.
If 0.15mm IS ADDED to endfloat measurement RATHER THAN SUBTRACTED with no shims then the bearings will be preloaded and the torque may be close to 3 to 5NM
With a 0.05mm pinch on the bearings I am getting a torque figure on the shaft of about 1.0 NM ..
the outer casing the differential tube runs in is aluminium the differential tube is steel therefore different rates of expansion... do i preload the bearings ? If so do I preload the bearings by enough to create torque of 3 to 5NM which seems a lot?
thanks for any help mark
