Welcome to William’s Tech Tips!

Need to replace your final drive seal?  Here’s what you do…

[This applies to 1970 through 1984 dual shock BMW models.]

The final drive seal output shaft is a common source of oil leak, and it’s an easy seal to replace, if you know how.

Removing the cover is easy enough; all you need is a couple of M5 bolts to press the cover off by means of the threaded holes in the cover. Knock the old seal out, clean the cover thoroughly, then install the new seal into the cover.

At this point, there’s a danger in possibly damaging the new seal when it passes by the many sharp edges of the final drive output splines. The following solution is as cool as it is simple…

When you install the cover with the new seal, it’s imperative that the seal settles in its home undamaged. In this case, all you need is a soda can. Carefully cut the end off of the can with some sharp scissors and place it over the final drive output splines.


BMW Final Drive Seal Installation 1970-1984

Place a Soda Can Over the Final Drive Output Splines


Lube the seal with some LIQUI MOLY LM48 Assembly Lube and slide it over the can and into position.  Be sure to heat the cover with a heat gun so that it fits onto the roller bearing without tension.  As soon as the cover is in place, remove the can, and the seal will be installed undamaged.


BMW Final Drive Seal Installation 1970-1984

Be Sure to Use That Liqui Moly!


BMW Final Drive Seal Installation 1970-1984

Liqui Moly LM48 Assembly Lube – 50g


This trick works with most 12-ounce cans.

And there you have it!  Share this tip with your friends and call or email if you have questions!


William Plam
Technical Support
Wunderlich America
125 Hangar Way #160
Watsonville, CA  95076

Telephone: 831-761-1070, #1001
Toll Free: 866-830-9990