Brake vibration in my '97 GTP is driving me nuts. I know Pontiac
undersized the brakes in these cars but I went the first 85 kmi with
vibration free brakes and want to get that condition back.
I've replaced front pads and rotors and even had brand new rotors
trued by a machine shop and the vibration continues. There's no
vibration at low pedal pressure or hard pedal pressure, but at medium
pressure that's where the problem is.
The latest rotors are Raybestos PG Plus and the pads are PF carbon
1. The caliper pistons seem to slide smoothly and the pins are
lubricated. Is there any way to diagnose sticking caliper pistons??
2. I'm 95% sure my problems comes from the front end but how can I
eliminate the rear brakes as the culprit for the vibration.
3. I plan to check for bad hubs/tie rod ends using the shake the wheel
method at the 12 and 6 o'clock then 3 and 9 o'clock positions. Is
there a better diagnosis method?
4. It seems like vibration started when I switched from OEM to Ceramic
and then Carbon Metallic pads. I'm wondering if there's just an
inherent vibration that comes about by using pads that are adherent
vs. abrasive pad design.
5. I plan to make another attempt at bedding in the pads. I'm not
sure I ever got them hot enough for the proper bedding in/material
transfer as suggested here.
6. I also plan to check runout and will try and index the rotors in
hopes that might help.
Any other suggestions??? I don't want to indescriminantly replace
parts in the hope of it solving the root problem.?