Rear disc symptoms......

[Steviesam]

Morning all,

Just wondering whast the symptoms of warped (or pad deposited) rear discs are?

I ask because I have a small vibration when braking, but it comes through the car and pedal rather than the steering wheel.

It also only happens when the braking is quite heavy and at higher speeds ie 30 or 40 mph normal light braking is fine, but if braking from 70+ it can be felt.

Thanks

[morgrp]

Have you got a corroded abs reluctor ring?

[Steviesam]

I have no idea!

How would I check that?

[Chuck328]

Are you sure it's the rear disks?

Also, what kind of calliper? 2/4/6 pot?

I had pretty severe vibration from some 4pots. Simple fix was to clean the offending calliper (stuck piston) and replace a torn seal. Problem fixed.

[Steviesam]

Not sure at all it is the rear disc.

I was just looking at possibilities for that type of symptom.

Cheers

[HT281]

I might be uneven pad transfer onto the disc. The juddering is usually worse when the discs are hot and the juddering is really a grabbing where the pads are grabbing on an uneven layer of pad material on the disc. If this is the case you can feel the car pulsing as you come to a standstill.

It's usually caused by the driver keeping their foot on the brake when they come to a standstill after a heavy or prolonger period of braking, causing a pad imprint on the disc. It can also happen on a car that's laid up for a period and the disc has gone rusty with a clean section where the pad has shielded the disc from the weather.

Mine was caused by a sticking caliper that wasn't fully releasing after braking, therefore the pads and discs were getting very hot on fast runs and when you stop the pad was sticking to the disc even with no footbrake applied.

[Steviesam]

Thanks for the replies.

I put new discs and pads on today, and interesting the discs were OK.

I think the problem was the handbrake shoes on one side were so tight against the inside of the disc that I could not get the disc off.

Eventually it came off and the shoes had clearly been contacting the disc all the time. Sorted that ouy and it seems better, but not been far yet.

It would laso explain why it seemed worse after a few miles-it would have been heating.

Fingers crossed.

Edited by Steviesam on Saturday 19th April 07:30

[P I Staker]

For future reference you can usually tell if the rear discs are warped by pulling the handbrake up whilst driving, you'll feel the vibration.

[TheInternet]

P I Staker said:

For future reference you can usually tell if the rear discs are warped by pulling the handbrake up whilst driving, you'll feel the vibration.

Even if the handbrake operates as a drum, as in this case?

[P I Staker]

TheInternet said:

P I Staker said:

For future reference you can usually tell if the rear discs are warped by pulling the handbrake up whilst driving, you'll feel the vibration.

Even if the handbrake operates as a drum, as in this case?

If there's a high spot on the drum you'll feel that.


I obviously missed that bit from OP's last post, my sincerest apologies.