Weird Noises / Front Sprocket Troubles

[MF92]

Unfortunately I didn't take any pics, Iv thrown out all the broken bits but after you posted those pics (thanks for those by the way) the parts iv found look very similar to that original component, the bikes got just over 30k on it now so i guess that part has just broken down over time.

[MF92]

When you say you had both calipers in pieces, what exactly did you do with them?

Took everything out except the pistons, gonna take a look at them now!

[fazersharp]

I belive the plastic part is to keep noise down and if you see from my picture the chain touches it so perhaps on your 30k worn one the chain itself has slaped/worn and broken/ chewed the plastic and that would make noises and jumping as the chain went over,

[darrsi]

[quote author=darrsi link=topic=13084.msg148175#msg148175 date=1400069762]

When you say you had both calipers in pieces, what exactly did you do with them?

Took everything out except the pistons, gonna take a look at them now!
[/quote]

Okay, i'll hazard a guess that they'll be your problem. 

[Millietant]

Are the pads "cheap" or very metallic ?


Binding brakes means the pistons are not returning properly from the disc-face, or into the caliper, once you've let the brakes off.


This could be the pads sticking on the pins, but if you've cleaned and lubricated these, then I'd suggest the pistons are the problem - probably built up dried grunge around them (might have got into the seals as well). Personally, I'd do a proper caliper overhaul, taking the pistons out and cleaning the up (fitting new seals as well) - it's easy, doesn't take too long and doesn't cost too much.

[Dave48]

Are the pads "cheap" or very metallic ?


Binding brakes means the pistons are not returning properly from the disc-face, or into the caliper, once you've let the brakes off.


This could be the pads sticking on the pins, but if you've cleaned and lubricated these, then I'd suggest the pistons are the problem - probably built up dried grunge around them (might have got into the seals as well). Personally, I'd do a proper caliper overhaul, taking the pistons out and cleaning the up (fitting new seals as well) - it's easy, doesn't take too long and doesn't cost too much.

As said above. The blue-spots are excellent brakes when properly maintained but in order for them to work free & easy its vital to have the pistons clean & free to move in & out. A complete strip & clean & if it were me a set of new seals should sort the problem. Its a good idea to lightly smear some red rubber brake grease around the seal edges/outer reaches of brake pistons-this helps movement & acts as a seal against dirt & wet. If your brake pad pins are dirty/corroded cleaning them & using some copper grease will help the pads move freely.

[Paul]

I had a binding front brake issue about 9 years ago.


I concluded that it was because I'd put the wrong brake fluid in when I bled the system.


And the wrong brake fluid affected the seals which in turn stopped them acting like a spring to back the piston off when you release the brake.


In any event I replaced the seals put the right brake fluid in and it's been o.k. since.