Emergency help with an 81 auto.

Charlesm3 · Post by **Charlesm3** » Sat Jul 30, 2016 10:30 pm

Hi all. I'm posting here and on My e28.com in hope that someone can offer help quickly. I recently acquired a 1981 528i with 67k and an auto transmission (soon to be. 3.5 with a 5spd). Today I put 16" BBS wheels on it and jacked the car at each of the four corners to do each wheel. I then did some work on the interior which included removal of the lower console for some stereo wiring. During that work I moved the shifter several times back and forth through the gears with the car turned off to remove and replace the console.

All went great until I went to move the car. When I put it in drive it moved about 6 inches and then the diff seemed to lock up. When putting the car in reverse it does the same thing...6" and then a lock up. Several times of the same exercise brought the same results. I even replaced the rear wheels with the original 14" setup to be sure it wasn't a fitment issue. It isn't.

Please help if you can. The car is immobilized.
Best,
CC

Mike W. · Post by **Mike W.** » Sun Jul 31, 2016 1:05 am

Does it drive, did it drive? Stick it in gear and see if you can go anywhere. Moving 6" seems like too much for an E brake problem, almost sounds like the diff. But a bad diff at 67K? With an A/T?? Unheard of unless it was run dry. See if you can isolate it by wheel. Jack up a side and try turning a wheel with it in neutral. Then try the other side. That should help determine if it's wheel/hub or diff/tranny. Pull a halfshaft, thought it might be hard if you can't rotate the tire. But even at the diff for troubleshooting. Once you figure out a why we can figure out a way.

wkohler · Post by **wkohler** » Sun Jul 31, 2016 2:44 am

How long were the wheel bolts you installed?

Charlesm3 · Post by **Charlesm3** » Sun Jul 31, 2016 6:04 am

Holy cow Chris, I think you nailed it! The car is at my shop so I can't check until later today but yes I did use the wheel bolts that came off the e24 donor car...they were noticeably about 3/8 longer.

I'll post the results of changing out the bolts later today.
Thnx.

Mike W. · Post by **Mike W.** » Sun Jul 31, 2016 12:29 pm

If that's the problem you can get away with much longer bolts in the front but not the back since they can hit the E brake hardware. The front is pretty much hollow.

Charlesm3 · Post by **Charlesm3** » Sun Jul 31, 2016 12:46 pm

Thanks Mike and Chris. Chris, you were right. I switched all bolts back to the original lengths and all is fine now.
Best,
CC

RonDwyer · Post by **RonDwyer** » Tue Aug 02, 2016 5:54 pm

Making sure things spin freely at the conclusion of each step is good procedure to follow. As is not tightening any bolts until they are all started in their respective holes.