Technical brake noise when turning slightly left

[boilermansab]

I seem to be getting brake noise, like pads touching discs when turning the wheel left slightly...they are new pads and disc...done about 3k miles on them...the set before done the same...what can it be? I cleaned the guides and everything before and the pads moved freely..

 

[widemouthfrog]

I'd have a guess that it's worn slider guides in the calipers. They're plastic and quite soft. Big Redd sell them as part of a refurb kit.

 

[boilermansab]

What part do you actually mean?
Thanks

 

[BikeDoc]

Brake noise when turning slightly left

The part of the caliper with the piston in, slides in and out on a pair of pins that are fitted to the caliper mounting itself.
The 'bearings' in the sliding part that take the load are plastic as wmf pointed out (more like a hard rubber actually), and once they start to wear out (or deform slighly from the continuous loading under braking), it allows the sliding part to move around a bit, particularly while braking.

Mine went last year, and when I braked hard, the caliper was moving outwards (radially) enough to rub on the inside of the wheel rim, there's not much clearance there in the first place.

Whip your wheels off and give the calipers a good wrench around by hand, any untoward movement should be noticeable.
You can lever carefully between parts of the caliper (and the caliper and disc) to see what's what as well, just don't put too much force into it.

 

[boilermansab]

Is it an easy fix the?

 

[widemouthfrog]

I had my calipers refurbished by Big Redd, but the bushes themselves are easy enough to replace. You just prise them out of the caliper and press the new ones in (all by hand). You have to remove the calipers from their carrriers first, of course. The kit I mentioned includes new slider pins as well as piston seals etc, I think.

Another tell-tale for worn slider bearings is uneven wear of the inside and outside faces of the brake disc.

 

[boilermansab]

So its just the rubbers that are likely to be worn...
Seen them avaliable on their own but for fords etc but they look very similar..

 

[BikeDoc]

Brake noise when turning slightly left

I bought replacements for mine, but they were no better than the knackered ones

I machined up some myself in the end, from Delrin (a proper Engineering plastic), no problems since...

 

[boilermansab]

I bought replacements for mine, but they were no better than the knackered ones

I machined up some myself in the end, from Delrin (a proper Engineering plastic), no problems since...

Fancy making some more and selling them?

 

[BikeDoc]

Brake noise...

So it's just the rubbers that are likely to be worn...

That's correct, the pins should be OK as the sleeves themselves take all the abuse.

Fancy making some more and selling them?

To be honest, no!
I couldn't make them with an integral 'cap', I had to fit a makeshift cover for them.
I wouldn't like someone to fit them and have them fail for want of regular checking.

 

[boilermansab]

Swapped them over this morning and it doesn't seem to have made a difference...still brake noise on turning in one direction and not the other...
What are the symptoms of a sticking caliper piston?

 

[widemouthfrog]

Uneven wear when comparing the inside and outside faces of the same disc. It was very obvious when I did mine - the outside face looked ok (but a little grooved) while the inside face of the same disc was corroded. The piston was partially seized, but originally caused by the guide bushes giving out.

 

[boilermansab]

The outside face of the disc is definately in better shape than the inside..there is no corrosion though..the pad is fully sweeping the face both side...
Might be one of those things ill just have to put up with...
Was going to try changing the brake hose as I've heard before that they can start to collapse and cause issues..