control arm installation problem [Archive] - Bimmerfest - BMW Forums

: control arm installation problem

11-04-2008, 03:55 PM
I have been doing the upper and lower control arms on my 92 525. Everthing went fine taking the parts off and reinstalling the arms. I now have the car with the wheels back on and the car on ramps to tighten the 22 mm nuts on the bushing side. The upper control arms torqued down just fine but when I tried to tighten the nuts for the lower control arms the nut would not tighten all the way. The nut started straight and true on the threads and I finger tightened them till they were next to the frame, but then I put the wrenches on them and tightened but the nut just keeps spinning and not tightening. I am holding the bolt with a second wrench and it is not turning which does not make any sense to me because the nut should be tightening. Both sides are doing this and I am wondering what could be happening. The nuts are new self locking nuts that I ended up having to get from the dealership so they should be the correct nuts and they fit fine. Is there something I am missing here because I am at a loss as to what the problem is. I was trying to complete this project mon and tues but obviously I didn't quite make it. I am going to try and finish tomorrow but have to finish by friday so any help or suggestions and even crazy ideas would be appreciated.

My only idea as to how to fix this is to place and extra washer on the bolt to tighten the nut farther away from the frame but I think the self locking part of the nut would not be touching the bolt if I did this and did not know if that would cause a problem, my thought about this is that the threads are damaged. :dunno:

11-04-2008, 05:06 PM
you striped the bolt it the nut isnt tightening

11-04-2008, 05:07 PM
do you have to big of a socket on??

11-04-2008, 05:13 PM
I have the right wrench/socket on the nut and bolt the bolt head is 19 mm and the nut is a 22 mm. How could I tell if the threads are striped b/c I have never striped any bolts and am not sure how to inspect. Why would both the left and right have striped at the same point. Thank you for any help you can offer I really appreciate the quick response.

11-04-2008, 05:23 PM
en you look at it, the threads will be really thin sometimes and its shinny, or is the nut the same nut that you pulled off the car the first time??
because if you got a new one it may be a little to big. even if its a little big it still hold it its one since bigger but when your try to move it, it come off the threads. you need a 19 mm nut.

11-04-2008, 05:24 PM
One more thought on it would be that I could have installed them backwards. How exactly do self-locking nuts work should the tapered side with no threads be pointing toward the head of the bolt or away from the head of the bolt. This may sound stupid but I really am trying to figure out what could be going on

11-04-2008, 05:29 PM
I had to get the nuts from the dealer b/c I could not find them anywhere else the parts guy said the nuts for the upper and lower control arms were the same, was he wrong are the nuts different?

11-04-2008, 05:38 PM
yeah they could be backwards

11-04-2008, 05:40 PM
Do you know if the tapered end should point towards the bolt head or away from the bolt head b/c right now I have them on where the tapered end points away from the bolt head.

11-04-2008, 05:43 PM
it shouldnt be tapered is this the thrust are bolt???

11-04-2008, 05:48 PM
The nut or bolt is not tapered I was just trying to describe which side of the nut I was talking about I'll find a picture and post what I am trying to say.

11-04-2008, 05:52 PM
the "tapered" side of the nut is pointing up in this picture

11-05-2008, 04:57 AM
any other ideas I'm going to take an hour or so and take another look but then I have to go to class, I should be back around three or four to work on it but I'll be checking this board between breaks all day if anyone could offer any more help. thank you all for reading and helping.

11-05-2008, 05:51 AM
You did not put the nut on back-wards. That is almost impossible for you to do. Remove the bolt and inspect the threads. I would imagine that the Nut is what stripped. Replace the nut and do it again. Be sure not to over tighten the nut. If it strips again you will need to find a different type that is a bit harder, just because it came from the dealer does not mean it is the correct hardness for your application.

11-05-2008, 12:51 PM
I'm sure you will all be glad to know this story has a happy ending. The nut was wrong from the dealership. I called them back this morning and tried to figure out why the nut wasn't tightening and it turns out the guy sold me the nut the attached the ball joint to the steering plate not the nut for the bushing/frame side of the control arm and the lower control arm calls for a 13 mm diameter where the nut he sold me has a 14 mm diameter, which is why it felt like it was fitting but then would fall off the threads when tightening. The good news is that I have the correct nuts now on my car and everything went smoothly on the test drive. The vibration around 50 is gone and I couldn't be happier saving the labor cost of doing this repair myself. Thank you guys for you help and quick responses.

11-05-2008, 12:55 PM
damn dealership

bimmer dot info
11-05-2008, 01:48 PM
Damn parts guy.

11-05-2008, 04:15 PM
Hurray!!!!!!!! :beerchug:

11-06-2008, 03:22 AM
:smokin: Man, I LOVE success stories! thanks for sharing!!!! I got the same car, so now I know what NOT to get!!! :smokin:

11-06-2008, 05:15 PM
you learn something new each day". Hope they gave them to you for nothing, since they screwed up.

But I also learned what "not to do."



11-06-2008, 06:25 PM
i like happy endings