Scrapping brakes and vibration at speed

[soufriere]

I have two intermittant problems that have recently started. The first is under braking at speed i get a scrapping feeling in the brakes as if there is something caught in between the disc and pads on the front of the car. It is as if the pads are worn but there is plenty of life left in them. The second is that i have an intermittant vibration through the steering wheel at speed. Could it be something as simple as the wheels needing balancing or a lost weight or could it be something more sinister. I would be grateful for any ideas or advice. Thanks, Mike.

Edited by soufriere on Thursday 27th July 22:20

[2 sMoKiN bArReLs]

Warped discs can give the wobbly feel under braking.

[soufriere]

Thanks for that. I don't seem to notice a wobble on braking only on acceleration at speed. The scraping feel is the worry on braking from speed.

[2 sMoKiN bArReLs]

Wobble probaly balance then. Dunno about the scraping.

[GreenV8S]

When you say there's plenty of life left in the pads, have you inspected all of them? If the caliper sliders are sticking the pads may be wearing unevenly, you may also find your pads are suffering from overheating.

[soufriere]

I had new pads put on the rears about six months ago (3000 miles) and new fronts about a year ago (6000 miles). I have checked all four and they seem fine. How can i tell if the caliper sliders are sticking? or what could i use as a precautionary measure to stop them sticking? Thanks.

[TVR keith]

Could be a bit of grit tapped between disc and calipher

[GreenV8S]

soufriere said:

I had new pads put on the rears about six months ago (3000 miles) and new fronts about a year ago (6000 miles). I have checked all four and they seem fine. How can i tell if the caliper sliders are sticking? or what could i use as a precautionary measure to stop them sticking? Thanks.

Have you checked the inner pads as well as the outer ones? 3000 miles is enough to have knackered the pads if the sliders are sticking, although if the sliders were that bad you would have noticed uneven wear on the old pads too. Apart from uneven pad wear, the only real way to check for sticking sliders is to take the calipers off. You can't really check the pads properly without taking the wheel off, and at this point you can also check for debris between the pad and the disc, and also check for play in the bearings.

If the vibration is intermittant at constant speed, it is probably a worn ball joint, wheel bearing or track rod end. One other effect which can cause intermittant vibration is both front wheels slightly out of balance. When the two wheels are out of phase you get vibration, when they are in phase you don't.

[bigdods]

I had one disk turn blue the other day - clear sign of overheating, but no other symptoms no fade or noises. Quick panic, phone call to Silverstone performance and took it straight over. Turns out some crap had contaminated the pad (EBC Reds) - amazingly they popped the wheels off, removed and cleaned up the pads, lubricated all the bits that can be on the calipers (dont ask me Im not a mechanic!) then tested it all. No more blue , everything fine and I got the beast back in under two hours. They also checked all the other disks and pads while they were at it. £40 + VAT. Suggest for peace of mind at that price get your local indie to do the same.