W126 Frontend Vibration
 

I've had this problem for over a year but it is starting to get worse and I finally will have some $$ to address it soon so I want to get some ideas as to the possible cause. The vibration appears occasionally over 75 mph and frequently upon moderate application of the brakes. Sometimes it can be quite severe on a hard stop from high speeds.

Over the time since I first noticed this problem, the front calipers have been replaced (with no noticiable impact), the tires have been rotated, and the alignment checked. I'm wondering if this is a bearing or bushing problem (ie something in the suspension that is made much worse when the brakes are applied) or if it is a brake problem such as high spots on the rotors or perhaps even warping.

Any suggestions on how to determine the source of the problem without replacing lots of parts needlessly or on other possible causes that I may not have considered?

Thanks
jlc

Replace all steering components with any play on GPs. Look to the caster joints for a pattern failure.

Steve,

Just to be sure I understand...by steering components, I'm assuming you are including tie rods, pitman arm, idler arm, and the steering damper. Are there any suspension components that might be causing this problem?

Thanks
jlc

Partial Success
 

I replaced tie rods, center link, and damper last weekend. The vibrations are now much less frequent and less pronounced but still there. For some reason, however, all the wet weather we've been having here in NJ makes things a little worse.

I did notice while lieing under the car that the lower control arm bushings are shot which, if they aren't part of this problem, certainly aren't doing the car any good. This is NOT a DIY project that I want to tackle - suspension springs under compression are scary - so can anyone give me a ball park figure on what it will cost to have them replaced? Also, while I am paying someone to compress the springs and deal with these bushings, what other suspension parts should I have replaced to avoid double paying for labor?

Thanks,
jlc