New second hand bike. Front brake squeals badly ?!

jack.murton

Hello

I am new to mountain biking

I have a question about my front brake which doesn’t stop squealing.

I have tried all the basic stuff like disc cleaner, sanding the pads etc. Not really doing a lot tbh.

Can anyone advise what It could be.

I have Shimano xt brakes and rt81 discs

Thanks

Jack.

JBA

Have you tried realigning the caliper?

steve_sordy

If it has oil on the pads, they are pretty much doomed. When you cleaned the pads, did you also clean the disc?

The quickest way to fix this is to fit new pads, but assume that oil was the problem and clean the disc as well. Then bed them in properly.

You may have been ultra careful and are convinced that you never got oil anywhere near the pads, but it can come off the road if you ride tarmac at all.

tom_howard

If it were me I'd just replace the pads and disc. Remove the chance of one re-contaminating the other, thus going round in circles, and both can be had reasonably cheaply

swod1

Pads are past saving by the sound of it.

isopropyl alcohol on the disc and a new set of pads usually does the trick.

Never experienced it on a front brake, usually rear brake I’ve had it on.

Check calliper alignment, pads not central to disc will cause noise as well

kajjal

As above remove the wheel from the bike, clean the rotor with suitable disc brake cleaner and also clean the brake calliper thoroughly with the same cleaner. Once you think they are both clean run a white kitchen roll over them to make sure, any black marks mean it is not clean. The thin groove where the rotor enters / exits the calliper tends to be where a lot of the build up is.

Then fit new pads and you should be fine. The discs unlike the pads don't tend to absorb the oil etc. and can be cleaned easily enough.

jack.murton

Cheers for replies. After a long ride I’ve noticed the caliper is leaking from the bleed nipple. This has sin leaked onto my new pads and ruined the performance. The brake is a Shimano xt m8000. The bike shop seem to think it’s a new caliper but can the parts not be changed. Surely it could just be a washer/ o ring fail.

robertpb

Not if the thread on the caliper has been chewed by the nipple being poorly installed.

The Rookie

Depends on why its leaking really!

The nipple seals by a compression of its tip into the caliper body (there is no seal/washer/o-ring), if the caliper is damaged its a new caliper, if its the nipple then you need a new nipple!