Steering Vibrations (long)

[jumpman]

Ok, this is now driving me nuts.

I upgraded my front brakes to AP Racing 330mm a couple of months ago and at the same time, changed my power steering fluid since the car was in the shop anyway.

Anyhow, the car has developed a funny vibration that is sporadic. On downhill left bends at speeds between 18-30mph, the steering will start vibrating once I turn in. It doesnt occur on uphill bends nor on normal driving and it doesnt always happen.

I'm totally bugged as to the cause. I've changed the tie-rods, steering arm and bushings and am using longer wheel bolts. I've checked the wheel bearings 3 times and no problems. I had the tires balanced twice and done an alignment.

I still have no idea what the problem is.

The only thing left i can think of is possibly a tire problem or steering fluid issue.

Any ideas on what else I need to look at?

thx in advance.

[NLR]

Are you applying the brakes at the time the vibration is felt? If so, your brake discs could have excessive distortion or run-out, or the mounting bolts to the brake caliper or backing plate could be loose. Good luck.

[jumpman]

No brakes have been applied at all. Theres nothing wrong with the disc, we've double checked that. I have faith in the APs.

We checked the mounting bolts as well and the all the peripherals. This was the first thing we did.

Thats why we're stumped. But thanks for your efforts. : )