sleddriver wrote:OP: I understand your frustration. The sled is now 19yrs old. New tires, lower control arms, struts, spring seats, & bearings, new outer tie rods. Axles are > 10yrs old and not OEM. Replaced by indy before I understood the consequence of that action. Wish I had them back....
1.. Could be wheel bearings....could be. Listen with a stethoscope.
2. Doubtful
3. ""
4. Likely...especially if it gets worse with gas on/gas off. It has a longer torque arm. Carrier bearing could be worn or bolts loose. Hub bolts could be loose.
You are correct that its frustrating. I suspected the rack and pinion nearly 6 months ago and decided to replace the wheels and tires first since they were old and needed to be replaced - my daughter beat the wheels to death when she was learning to drive and the tires were just old. I replaced the tie rods just because they are classic root causes of high speed front end vibration. Of course, a steering rack with slop is going to act like a bad tie rod.
My inner and outer tie rods were replaced in August. They are lemforder and trw (or sdi cant remember) - OE parts. They are tight and as good as it gets. While I was doing that I had plenty of time to look at and diagnose the control arms. They are originals but the joints are tight...no slop. The rubber bearing covers on the control arms are split, but they are OK for now. In checking the tie rods I noted that there is, in fact, some slop in the rack. Its about 1/8" when holding the wheel at 9 and 3 o'clock. I can hear a tick sound (metal on metal) when I rock the wheel with a 3 and 9 o'clock push-pull. I've wondered about it as the possible root cause of the vibration but figured maybe the little bit of slop goes away when the steering system is under pressure. Others have posted threads about a small amount of slop in the steering rack as if it was normal. My steering rack doesn't leak and never has. I didn't post it as a possibilty because I ruled out it (but maybe I was wrong).
The vibration started about 18 months ago and has gotten worse with time. I've had 2 alignments in that time frame. Both shops who did the alignments told me that its not possible to adjust the rear. I believe the alignment is OK. I have my old tires in the driveway while I decide what to do with them (they have plenty of tread left and I may sell them). They are all evenly worn and near perfect for old tires. The rear tires are 4.5 years old Michelins. My vibration DOES NOT appear under acceleration (usually) - sometimes it does. I also sometimes get a slight warble around 50 mph which is barely noticeable and it goes away quickly. It always appears on deceleration from 70 mph down through about 65 mph.
Anyhow, it sounds as if we have the same or similar problem and, yes, I agree that it may be the steering rack. I really don't want to believe that because its a bigger job than I really want to do and will cost more than I want to spend to get someone else to fix it. I'm going to research it a bit and see what I can find, especially since you have the same nagging feeling.
