Grinding Noise from Back Brake

[brownetara]

Hiya, About three weeks ago, my brake light was staying on continuously, tried to loosen up the adjustment but couldn't get it right. Brought it to a garage, where the guy disasembled the brake pedal, cleaned it, hput some grease on it put everything back together, and off i went, happy out! Unfortunately, there is now a grinding noise coming from the pedal when i apply the back brake - generally i only notice it near the end of the braking i.e. when i've slowed down a good bit. Any ideas???

[brownetara]

Ok, the latest update, brought it to the mechanic, he reckoned there was a spacer missing from the back wheel, which was causing it to pull towards the brake caliper slightly and caused the grinding. HE fitted something to replace the spacer but its still happening, in fact i'd say it's worse! Anyway, it doesn;t happen when you apply the brakes hard but if you just dab them it grinds like a mad thing! Any ideas?

[Alba]

The brake like switch runs off a steel cable connected to the brake level just to the right of the rear master cylinder. When my brake light was staying on I lubricated the cable and cleaned the switch, light now working properly.

As far as I can work out from your post it sounds like there is a brake pad / caliper issue going on.

Did the mechanic do anything to the rear wheel / caliper?

Have you checked brake pad wear or caliper alignment?

[btbloke]

unless you've had the back wheel off and a spacer has fallen out (in which case the wheel would wobble and doing up the nut would bend the swingarm! this is unlikely as would be noticable to anyone who refitted the wheel) i would suggest there is no spacer missing. Take a pic of the rear wheel both sides where he put this spacer in and post it up,it could be dangerous!
Someone else on the forum recently had his rear wheel re-fitted with the spindle going in from the wrong side and therefore the nut holder on the wrong side,maybe they re-fitted it with the caliper not in it's retaing groove correctly which would cause a noise and seizure of the caliper leaving a gap between the correct spacer and the swingarm.
If it is grinding only when slight pressure applied to rear brake it sounds like you had/have some ****e in there. A liberal spraying of brake cleaner,leave to soak and another to blast everthing out from the nooks and cranny's normally works for me. The have a close look and make sure there are no little stones or bits of tarmac etc wedged in there. Then check you don't have a seized caliper.

[StumpyFingers]

I have had a grinding noise from my rear brake in recent weeks.
On the MOT they pointed out that the rear pads were near the limit.

[brownetara]

Thanks for the replies, i had the wheel out recently to change the chain and sprockets but it seemed to be doing it before then and i'm prety sure we put everything back together the right way, it did get a bit worse after that. The mechanic had the wheel and caliper out, checked it all over, checked the pads everything - i'm really stumped on this one! Help!! I need an inspired solution to this one! Its really annoying as i dont want to use the back brake now at all, and while thats fine in the dry weather, i live in ireland, its gonna rain soon!

[btbloke]

Here's some pictures of what the rear should look like:-

this is the rear spacer from the sprocket side and the direction it goes on




and it should look like this when in the sprocket carrier;



there should be another spacer the other side,it fits between the caliper bracket and the wheel in much the same way as the other one as in it fits inside the dust seal on the wheel.



the Wheel spindle should be inserted from the left if you are looking from the rear of the bike and the fingered plate should be on the nut side of the bike making sure the caliper slide is in the runner on the inside of the swingarm:-








when tightened and torqued up it should be tight both sides like this:-



the disc should run smoothly through the caliper,you may hear it touch slightly but don't worry this is how the disc and pads are not permanently touching.
Try getting someone to spin the rear wheel and apply the brake by hand,if it is very hard to apply it may be seized somewhere,whether it be caliper pot,caliper slider or the pads worn down to the metal. My pads are about half way worn so use this as a yardstick,if yours are thinner they may need changing.


I still would like to see this spacer the mechanic fitted because no mechanic worth his salt would fit anything to a wheel or that area that wasn't supposed to be there and by that I mean designed to be there by the manufacturer and fitted by the manufacturer and there when you went to see him in the first place. I don't want to scare you but it's only your life your playing with when you modify the bike.

[Alba]

Thanks for the replies, i had the wheel out recently to change the chain and sprockets but it seemed to be doing it before then and i'm prety sure we put everything back together the right way, it did get a bit worse after that. The mechanic had the wheel and caliper out, checked it all over, checked the pads everything - i'm really stumped on this one! Help!! I need an inspired solution to this one! Its really annoying as i dont want to use the back brake now at all, and while thats fine in the dry weather, i live in ireland, its gonna rain soon!

blbloke has given you some good info here, I would strip the lot down and double check every thing, also check the three rear wheel bearings are running free (potential bearing failure springs to mind), taking your time reassembling.

Lets know how you get on...

[Lutin]

Well, I can guarantee that the rear wheel was put back in place correctly - as I helped Tara do it.

Didn't have time to have a look at the back brake after replacing the chain and sprockets.

[brownetara]

Well, I can guarantee that the rear wheel was put back in place correctly - as I helped Tara do it.

Didn't have time to have a look at the back brake after replacing the chain and sprockets.

I never doubted ya! I'll get to the bottom of this if it kills me. Had the bike up on the paddock stand last night and the sound is definitely coming from where the pads touch the disc??? There's plenty of meat left on the pads so i've no idea whats going on? Maybe i should just try new pads?

By the way, welcome back! Nice time in Wales?