Yet Another Rubbing Question...but I have researched already
 

Okay, I've waited a couple months before coming for help. I've looked things over many times, searched the forum, BMW-mechanic friend looked at it, and an independent BMW shop in town looked at it and the opinion was everything is installed correctly. Ok, details.

Problem: The back right wheel rubs the fender. Only the back right, not the left. It happens on dips, bumps, and hard left turns. Having weight in the back, 30-40 pounds, makes a difference. When nothing is in the hatch it takes a much bigger dip for the rub; left turns still rub. The noise I hear is sort of like a crunch/grating. The loudness and length varies with my speed and duration of the turn/dip/bump.

Setup: Bilstein sports with RSMs and ACS springs. The springs were purchased used on the forum and the shocks were purchased used, but not installed, on the forum as well. RSMs new from Turner. Other modifications in the back is HR sway bar (used from forum) and LSD (used from craigslist). One piece Style 5 (16x8, ET 23), installed before the springs...no rubbing at this time. New brakes. The LSD and sway bar were installed after the problem. The shocks were installed before the problem, before the springs. The problem began after the springs were installed. Also should be noted that I drive the car on dirt roads now and then when camping/hiking. These aren't 4x4 roads, they're graded evenly, but there some bumps and washboarding. However, the problem did start on paved roads...right after the springs.

Thoughts: I am sure (though only working on cars for a year now) that it is the springs in combination with the wheels. I know they are not the stock offset. My main question though (besides if I am wrong) is why only the right side rubs? Does this indicate that the one spring is bad? My friend seems to think it is not rubbing and it could be something else...half shafts or bushings. New bushings went in with the sway bar, but no others in the subframe have been swapped yet. But, I can see the wear line on the tire and the polishing in the fender, so I know there is rub. Maybe there are 2 things happening, but definitely a rub. All parts look tight and installed correctly, this has been checked over. Nothing cracked or broken. I do plan on putting the stock springs back on regardless, but was curious for some input in the meantime. I'd hate to do the springs and find out I was wrong. The shock looks ok.

Final Thought: Swapping the springs out seems like the obvious, easy fix to this loooong winded post. I think the lowered spring and ET 23 wheels are the culprit, but I would have thought both sides would rub (only 1 year experience though). Is one side normal, or does it indicate something is wrong with the rear subframe or does it indicate the spring is bad?

I can attach a couple pics of the back, but I don't know if they will help. If anyone has specific questions or needs a pic of something else, let me know. Sorry for the long post for a simple question, just wanted to try and get as much needed details in originally. Thanks for any input; it's appreciated.

Sidenote...I will be LA end of month of anyone needs any of the rear parts I took out. Driving out, so can throw in the hatch.

Are you sure it's the fender rubbing and not the top corner of the rear bumper where it meets the wheel arch? Check this out: http://www.318ti.org/forum/showpost....1&postcount=73

Thanks for the quick response, I was thinking you'd have some help to offer. Based on where I am seeing the polishing it is the area circled in green in the attached pic. Right on the inside where it folds over slightly. I can pop the wheel off tonight and get a couple shots of the rub also if it helps.

I've done no fender rolling, as another setup side note.

Well that's your issue right there. You're running 5 series offsets on a lowered e36, you need to roll your fenders. sheesh:tongue:

They're 16x8, et23 came off the 7 series. I know that is not the stock offset. These wheels with the springs I know cause the rub, but I guess my main question is it normal that just one side rubs. If normal, I am not worried...I'll just take care of it. If not normal, then I am trying to figure out what the problem may be, whether a bad spring, shock, or something else in the subframe.

Are the part numbers on the springs the same? If you swap springs right to left does the rubbing follow?

Do you have the same thickness spring pads on both sides? Are the rear ride heights the same?

Good questions...I haven't swapped them right to left to troubleshoot, that's a good one. Part numbers are good. Springs "looked" fine and the member I bought them from was top notch. Same thickness spring pads on each side. Possible one wears quicker than the other? I haven't measured with a tape, but visually the right side has looked slightly lower. I'll get a measure on it and maybe try swapping right to left before changing out the springs completely. Thanks for the input.

BMW never intended for people to run low offset wheels on the e36. The fact that only one side rubs is not necessarily due to defect or damage as the factory wheels and tires had plenty of clearance. If you want the rubbing to stop, roll your fenders and be done with it.

Also, make sure all 4 of your wheels have the same markings. It's possible that someone might have replaced one with a lower offset 5 series wheel.

Are you running same brand tires on both left and right rear some wheels tend to be a bit meatier than others?

Yeah, same all around. Hankook Ventus right now which are new. Goodyear Eagles previously and same issue.

205/55/16 on both sets.

Measure your control arms in the rear, basic geometry, form the inner pivot to a common spot on the trailing arm near the axle just too rule out a bent arm. Worn out bushings can make it worse as well.

Dave

Thanks Dave. Will do.

Measured and control arms are good. Bushings are good as well.