1972 BMW R75/5 - Rear Drive Shaft Boot Shavings?

Good morning to you all,

Yesterday I cleaned up the rear swing arm area and removed the transmission drive shaft transition boot, turned it inside out and discovered the following fillings. Where would have this come from?

Could they be broken washers? From the factory they would have used long bolts with washers. They could break and the bolts would loosen creating havoc. Replacement bolts are shorter with no washer.

Are the pieces steel or aluminum? Looks like aluminum to me.

poorub said:

Are the pieces steel or aluminum? Looks like aluminum to me.

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Good Question! Will check.

Wherever it came from it can't be good.
Hope you find the source and its a easy fix.

Those are aluminum threads from one or more shaft housing fill/drain plug holes in the final drive...

Those are aluminum threads from one or more shaft housing fill/drain plug holes in the final drive...

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If they ARE aluminum (looks like it), that's about the only thing I can think of too.

Keensert time...

Definitely threads; but from where and how did they end up where they did...…….Is it making any shouldn't be making noises....Grinding???

The rotation of the driveshaft pulls gear oil forward towards the gearbox.

PAS said:

The rotation of the driveshaft pulls gear oil forward towards the gearbox.

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- what PAS said. I would add that the oil moving towards the gear box washes through the bearings in the "U-joint" from centrifugal force carrying any odd debris with it of course - which is how the bits wound up in the boot.

Check the fill drain plugs on the final drive. Specifically, the threaded holes one near the stamped numbers representing the gear ratio - and the one below it. You will either see threads or no threads. Possibly, a thread insert repair. Those are the fill and drain holes for the steel drive shaft housing. The actual final drive drain is on the housing bottom at 6:00 and the fill hole is at the rear of the housing at about 9:00. If you find nice clean original threads I'd bet the bits are from an earlier final drive unit. The plugs only need a few ft lbs of torque on new washers to stay put.

b25bsaboy said:

Good morning to you all,

Yesterday I cleaned up the rear swing arm area and removed the transmission drive shaft transition boot, turned it inside out and discovered the following fillings. Where would have this come from?

Click to expand...

Thank you to all that responded to my question.

Found the culbert, as it appears when I drained all the oils, I didn’t pull or back out the top filler plug and it appears the PO was a little bit heavy fisted.

Guess its HeliCoi or Time Sert time again