Brakes not contacting entire rotor

[dlundblad]

This is with my brothers 1998 S10 Blazer.

It looks as if the rear driver brake is only contacting about half of the rotor. (Half is shiny and the other half is rusted.) Will a warped rotor cause this or is it a faulty caliper?

We are going to be replacing the pads/ rotors as well as flushing the brake system this weekend so might as well replace the caliper if needed.

Thanks guys.

 

[Brybo86]

I bet the pad has a pin on it and the caliper was not rotated correctly causing the caliper to only squeeze the pad on one edge.

At least that's how my Honda works...?

A simple picture would be useful if you want meaningful answers....

 

[BRZED]

I suspect a sticky caliper, resulting in uneven pressure. Could be worn or gunked up caliper slide pins.

 

[dlundblad]

Originally Posted By: Brybo86
I bet the pad has a pin on it and the caliper was not rotated correctly causing the caliper to only squeeze the pad on one edge.

At least that's how my Honda works...?

A simple picture would be useful if you want meaningful answers....


I have no photos.

Here is what it looks like. Same general area, but not as much rust or contrast in wear between the 2 areas.

 

[Quest]

If rear brakes are disc type, chances are: the caliper slider pins maybe sticking.

Aside from inspection (for rusts within the bore which may lead to guide pins binding and more), relube guide pins (if the bore and dust boots deemed ok), also get a big G-clamp and see if you can push the piston back and while you are at it: see if the motion (of pushing the piston back) is smooth. If any slight bit of binding, you can then safely assume that the piston needs to be replaced, or the whole caliper needs to be rebuild (new piston + seal + new dust boot).

New rotors needed in this case, and a fairly aggressive break-in process necessary initially to get the pads to "bite" and bed in properly. After that: it's just a matter of taking it out frequently for drive, and ensure that the rear brakes get exercised regularly as well (to keep the rusting to a minimum).

Q.

 

[Robenstein]

I second the slider pins. This happened on my car a couple times. Time to bust them apart, clean them, use a good caliper pin grease,and probably put a new hardware kit on it. That is what mine took to get working right again. I threw a new set of pads on it too at the same time.

 

[eljefino]

Slider pins and possibly the pad ears are tight in the bracket. Usually the bracket rusts and swells, but the pad ears are more convenient to grind so it all fits.

Pull the shiny chromey anti rattle clips (abutment clips) and chisel rust and brake dust out of there with a flat screwdriver or whatever you need.

You should not have to pry pads out, or bang them in. They shouldn't be so loose they fall out on their own, IMO, but close to it. Too loose makes noise.

 

[Vikas]

Quote:
If rear brakes are disc type, chances are: the caliper slider pins maybe sticking.
I thought the topic title had word "rotor" in it! Are there other types of brake where brakes do not contact the entire rotor?

 

[camrydriver111]

Everyone blames the sliders but I have this problem with nearly brand new brakes.

I had a brake job this summer. Everything was perfect and pads contacted the whole surface.

A week ago my brakes were taken apart and put back together. For reasons I don't want to get into but not brake related.

Now the pads don't contact the entire surface.

I think it may have to do with the practice of applying grease to the backs of pads. You are effectively shimming the pad with grease. When things are taken apart you are disturbing the grease and the pad does not go back the way it was.

If you haven't had a brake job in a long time it could be the sliders though or pads binding up in the bracket.

 

[Brybo86]

judging by the pic i think you need to take this thing out on the interstate.

make sure no one is behind/around you and do a couple pedal to the floor stops

it looks like you are a really slow driver and never push the brake pedal more than a tiny bit....

center of the pad heats up first and cools slower than the outside of the pad and so that is where the contact is first.