Suspension Problems?

[m3f_romh_9db5ad5d95]

Steering wheel shake a hiighway speed can be a sign of bad control arm bushings.

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I do have that problem. Just 1000 miles ago I had all 4 tires balanced with the road force variation balancing, and they all balanced out. And I still have the vibration at highway speeds. It starts at 70mph and gets a little worse the faster you go after that. This is weird. If I floor it on the highway, for the seconds that its accelerating, there's no vibration, but when I let go of the acelerator and the car jerks forward, the vibration worsens to a bigger level. After that, the vibration continues at a slightly less level.

Did I give you any clues as to what it might be? The bushings as you mention?



Is replacing those bushings an easy DIY in my garage over the weekend? Did you do all the work yourself?

[m3f_romh_9db5ad5d95]

SG_M3:



I just saw the post you did on the control arms where you state that you did it in your driveway.

[m3f_SG_M3_d1201712b5]

That sounds very much like a bad control arm bushing. You can crawl under there and look for cracks in the bushing.

[m3f_romh_9db5ad5d95]

The place that balanced my wheels told me that my front upper something was damaged. I wasn;t really paying attention because I really want to take it into the dealership. I have a hard time trusting mechanics that work on all sorts of cars and not just BMW's. At least that;s what my friend mechanic that works at the BMW dealership advises. I would agree. The BMW guys have been doing it for years and years exclusively on BMW's. Of course, you have to have one the experienced mechanics working on it. That's why I asked him who the best suspension mechanic is at his store. Some guy there has been doing alignments and suspension stuff for the past 25 years. So I want that guy to give my car an inspection. He tells me what's wrong, I order the parts, install them myself, and take it in for an alignment.

Sounds like a good idea, right?

[m3f_300ZXNA_1b0983de7b]

as to replacing the RTAB's, I bought polyurethane bushings from bimmerworld.com and have been extremely happy with them. Definitely fixed the problem.

[m3f_romh_9db5ad5d95]

thanks, i'll check those out

[m3f_SG_M3_d1201712b5]

IMO, poly is bad material for those bushings.

[m3f_300ZXNA_1b0983de7b]

from what standpoint is poly a bad material for RTAB's? Durability, performance, ride quality? I have not noticed any negative aspects from them other than the occasional squeak. Anyway, expound on that if you could . . .

[m3f_SG_M3_d1201712b5]

I've seen 4 cases of blown out poly control arm bushings on track. Poly rtabs give you a rise in NVH, while 96+ bushings with gc enforcers are just as stiff, but not the rise in NVH.



Just from my experiences.

[m3f_300ZXNA_1b0983de7b]

hm, good to know. I have auto-xed my car a few times, but I have not tracked it nor do I plan on tracking it, so hopefully I will not run into that problem. However, if I do, I now know what to replace them with. Thanks . . .