Monolever bevel drive rebuild - update.
Posted: Thu Mar 03, 2011 1:09 pm
MONOLEVER bevel drive -
If I remember, a couple of people wanted to know how this rebuild turned out. Be warned, this is pretty dry stuff to read.
Not finished yet, but...
Put the new monster bearing on the crown gear with the freezer/oven technique.
The crown/pinion backlash is determined by the shim size between the crown gear and the inboard bearing. After monkeying around with some home-made plastic spacers I ordered a shim that would be close or too small. It was both. I added to that with shims made from a beer can which, conveniently were 0.1mm. Then the measuring part which was a little difficult - trying to hold the crown gear in true and square while still being able to move it against a dial indicator. I have now ordered another inboard shim that should put the backlash within specification or very close to it, which will be a large improvement. Taking measurements to determine the outboard shim size are difficult and I believe the necessary accuracy will elude me with the equipment I have. However, the distance from the outer cover to inner bearing will not have changed so the "stack" of items between them would need to be the same size. To that end, I have ordered an outer shim that is 0.3mm larger to offset the inner shim, making the total the same. This means that any preload exerted by the outer cover should be the same. I am assuming that BMW got that right initially but I am OK with that. Sometimes you gotta trust someone.
I won't receive those shims for about 10 days. The suspense is killing me.
If I remember, a couple of people wanted to know how this rebuild turned out. Be warned, this is pretty dry stuff to read.
Not finished yet, but...
Put the new monster bearing on the crown gear with the freezer/oven technique.
The crown/pinion backlash is determined by the shim size between the crown gear and the inboard bearing. After monkeying around with some home-made plastic spacers I ordered a shim that would be close or too small. It was both. I added to that with shims made from a beer can which, conveniently were 0.1mm. Then the measuring part which was a little difficult - trying to hold the crown gear in true and square while still being able to move it against a dial indicator. I have now ordered another inboard shim that should put the backlash within specification or very close to it, which will be a large improvement. Taking measurements to determine the outboard shim size are difficult and I believe the necessary accuracy will elude me with the equipment I have. However, the distance from the outer cover to inner bearing will not have changed so the "stack" of items between them would need to be the same size. To that end, I have ordered an outer shim that is 0.3mm larger to offset the inner shim, making the total the same. This means that any preload exerted by the outer cover should be the same. I am assuming that BMW got that right initially but I am OK with that. Sometimes you gotta trust someone.
I won't receive those shims for about 10 days. The suspense is killing me.
