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 metallics.
- The caliper pistons seem to slide smoothly and the pins are lubricated. Is there any way to diagnose sticking caliper pistons??
- 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.
- 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?
- 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.
- 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.
- 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.?