1 Shimming preload in the final drive Tue Jul 17, 2018 6:26 am
halflive
Silver member
The problem.
I have a howling sound from my final drive on motorway speeds. Main suspect is the large ball bearing.
Easy way is to buy a new bearing and replace it. Two disadvantages, I do not have a thin enough puller, the bearing is expensive.
My solution:
I have another final FD lying around which is good. The new challange: It is a drum brake, I need a disk brake. Challenge accepted, change the cover plate.
Now my real problem starts.
To obtain correct preload on the tapered roller bearing i need to place shims between the large bearing and the cover plate. I expect the shims to be different in my two covers.
The official method is (short) to measure the difference between the bearing outher ring and the mating surface and the recess in the cover and the mating surface. adding 0.05-0.1 mm to the difference should give enough preload.
Not to difficult if you have a depth gauge. Sadly i only have a common caliper en not the BMW fixing ring.
Has anyone tried it by bolting the bearing down with M8 bolts and large washers? Is it possible to get relyable measurements that way?
Has anyone measured the cover depth by using two lying drills as compensation for the ridge in the cover plate and using a steel ruler as bridge to compensate for the depth gauge? Is this a relyable method?
Has anyone tackled this challenge before? I know people have replaced cover plates but cannot find any reports on the net. Does one of you have a link to a report or a video?
Secondly, i read about a method using solder wire to obtain the shim thickness. Is this a relyable method? If the lead is compressed does it stay in the shape or does it bounce a little and expand a bit from it's compressed state?
Yes, i'm aware this is not the easy way out.
I have a howling sound from my final drive on motorway speeds. Main suspect is the large ball bearing.
Easy way is to buy a new bearing and replace it. Two disadvantages, I do not have a thin enough puller, the bearing is expensive.
My solution:
I have another final FD lying around which is good. The new challange: It is a drum brake, I need a disk brake. Challenge accepted, change the cover plate.
Now my real problem starts.
To obtain correct preload on the tapered roller bearing i need to place shims between the large bearing and the cover plate. I expect the shims to be different in my two covers.
The official method is (short) to measure the difference between the bearing outher ring and the mating surface and the recess in the cover and the mating surface. adding 0.05-0.1 mm to the difference should give enough preload.
Not to difficult if you have a depth gauge. Sadly i only have a common caliper en not the BMW fixing ring.
Has anyone tried it by bolting the bearing down with M8 bolts and large washers? Is it possible to get relyable measurements that way?
Has anyone measured the cover depth by using two lying drills as compensation for the ridge in the cover plate and using a steel ruler as bridge to compensate for the depth gauge? Is this a relyable method?
Has anyone tackled this challenge before? I know people have replaced cover plates but cannot find any reports on the net. Does one of you have a link to a report or a video?
Secondly, i read about a method using solder wire to obtain the shim thickness. Is this a relyable method? If the lead is compressed does it stay in the shape or does it bounce a little and expand a bit from it's compressed state?
Yes, i'm aware this is not the easy way out.