I noticed something odd about the rear brake discs on a 2002 S2000 I am thinking of buying. On one side the shiny band made by the pad on the surface of the rotor was quite narrow compared to the other side, as if the pad wasn't touching the surface of the rotor properly. The swept area was a lot less on one side than the other. The width of the shiny band was only about 2cm - I'm sure the pad is a lot wider than this.

What would cause this? Is the caliper seized on the slider pin and not functioning properly? The brakes seemed to work OK, and the car has recently had its annual UK safety inspection (MOT - it isn't very rigourous but does check that all 4 brakes are functioning adequately).

many thanks,
Duncan

 

No ideas? Is it common for the rear calipers to seize, and is this one of the symptoms?

cheers
Duncan

 

Take a pic

 

Yes, it is likely that the pad is not aligning with the disk and I would start with the sliders.

 

the piston was not aligned with the pad.

there is a tab on the pad, and the piston must be aligned with this tab.

if you installed the pad yourself, you can undo and reinstall. otherwise, take it to the shop that installed and tell them the f'ed up.

 

this is your problem. there are slots in the rear piston made so that you can use a tool to spin and push the piston in at the same time. if the slot is not alligned with the little allignment tab or bump on the pad the pad will be pushed in to the rotor crooked.

 

Duncanreally Posted on Jan 19 2009, 02:42 AM
You're talking about the side of the rotors (L/R) you can see walking around the car?
If so, than the explanation of the inner pad not being installed properly is a presumption.

Take a pic, as mentioned.

 

It's not my car - it was a car I'm thinking of buying. I'll ask the owner if he can send me a picture.

To clarify, I'm talking about the outside side of the discs, what you can see walking around the car without removing the wheels or discs.

The car is otherwise in nice condition - I'm trying to decide whether it will need new calipers to fix this problem or whether it's something less expensive. Clearly its not right!

Thanks for the help so far, I'll try to get a picture.

Duncan

 

+1

I had the same problem when I installed my rear brakes. The pin must align with the slots.

 

This isn't the actual car I looked at, but I was looking at other cars for sale and this one has a picture showing a similar problem:

http://images.pistonheads.com/aimg/733/733389-5.jpg

See you the rust-free and shiny band on the disc is much narrower that the width of a pad?

Duncan