Hey guys,

So today I was driving home with a car loaded with some extra rims and all of the sudden started hearing something hitting the bottom side of the right rear -- thinking I had blown a tire I pulled over and saw nothing. I kept driving and kept hearing the noise -- like something hitting the bottom of the wheel well. Get home and can see visible scrapes on the inside right rear wheel well.

It also seemed to happen quite suddenly. One moment all was good and the next not so much. I took the wheels out of the car and went for a drive and no more scraping.

The right side also looks to be about 1/4" lower than the left side...and I can see that there is a bit more camber.

Nothing looks visibly out of place...any thoughts on what might drive this? Worn out right rear spring...really bad alignment?

Thanks.

 

My first guess would be a broken spring. But it could also be some other part of the rear suspension bent or broken. Take the rear wheel off and inspect, if something is broken it should be easy to spot.

 

There's nothing visibly wrong though..that's the interesting part. Tempted to take the rear springs and swap them left to right to see if that's the cause.

 

Are you just eye-balling it for the 1/4" or are you measuring something?

One of the springs might be a bit weaker than the other one I suppose. Could something in the suspension be bent?

But the fact that something is rubbing is of concern. Clearly one side is weaker than the other.

 

Not eyeballing -- measuring against a key -- went out there this morning -- the right side camber is WAY off. SO... took off the wheel -- pretty sure the upper control arm is bent.

trying to get a picture up (but failing) but think of a Z shape -- just milder. Pretty sure control arms are usually straight aren't they?

 

Right side is usually hammared with more potholes....
So bent parts or blown struts would not be unexpected...

 

Yup for independence day -- our first president (George Washington Bridge) nailed me with a huge pothole that I couldn't avoid. The noise started shortly after.

 

Check the front suspension also. If the back hit hard enough to bend the upper control arm, the front probably hit the same pothole first.

But yes, the rear upper control arm should be straight. My guess is that the strut is also bad and the control arm bent when the suspension bottomed-out.

 

Will do -- I'm pretty sure this was bent before...and this was the final blow. 1.5 years of living in Manhattan and commuting for work every day will do that. Happy to be out in the burbs with a place to work on the mini and park it not in the street now.

 

The rear control arms are pretty easy to replace but if you drive rough roads a lot, you may want to consider some upgraded suspension parts.

 

Hey Jwh...any suggestions on brands? Lots of upgrades for Lower control arms...didn't see much for upper.

 

These look pretty nice but I've not tried them:

http://www.harrisonmotorsports.com/h...and-lower.html

 

Check out outmotoring.com think they are cheaper

 

Thanks guys...I decided to go with stock for right now. Had it been the lower control arm I would have upgraded...money is not so free flowing these days. Couldn't justify double the cost.

Here is a picture of what you don't want to see

 

FYI upper and lower are the same. You actually could've swapped a good lower with the broken upper one and bought a pair of aftermarkets to use on the bottom

 

That's nasty! In this case I'd say the upper arm gave its life for a good cause!

 

Hey Andy where were you 4 hours ago??? Hah...it's okay my car isn't even lowered...probably never will be. I scrape coming out of my driveway now.

I couldn't justify 300 for a set of control arms right now...I don't track, race, etc...I drive to and from work 12 miles each way.

Got two on order with parts geek for 148 shipped...they say you are supposed to do them in pairs...I'm not sure why.

If the stock lowers after 99k miles are needing replacement (I'm sure they will). Maybe at that time I'll upgrade

 

So I wanted to share a picture of the old vs new design of the control arm. Upper is new.

I bent the old one back to show what stock looks like...two blows with a sledge.

Shocked that BMW let the old design go out....not shocked that people were having failures. Granted this is a lemfoerder (OEM supplier) version but I'm sure it represents a pretty accurate depiction.

My lowers are also the older design...suspect I'll be upgrading those when money allows.

 

Of course the bottom one will get TENSION when you hit a bump while the upper will be in COMPRESSION. I'm sure even the old design is strong enough to withstand the tension without pulling apart.

But you might want to swap the lowers out anyway just to be safe. They are remarkably different which is surprising.

 

Good points...yeah I guess it would take a lot to pull apart the lowers. The uppers take a bit more abuse I guess.

Swapped the drivers side upper the other day - was much quicker than the right side having been through it. The only complicated part about it was counter holding the bolt that goes into the rear subframe. There isn't a lot of room to get a socket and wrench up there. I used a breaker bar because it was thinner than my wrenches. A ratcheting 18mm wrench would have been great in this instance.