Grinding Rear Brake

Right, so back again!

Managed to get everything off and opened up after a day of fighting every single bolt on the calliper. Definitely needed some work (the dust seals had been caught and pushed part way out) and everything covered in crap. The one pad has been worn down to the metal since I had to ride it once or twice with the squealing brake...

Pistons are properly stuck so wondering if anyone has any tips to get them out - bearing in mind I don't have a spare air compressor hanging around!

Best bet is to refit the brake line, fill with fluid (as if you were re-assembling them for use) and pump them out with the brake pedal.

The curvy has a proper opposing piston rear calliper so one will probably want to pop out first so stop that one coming all the way with a G-clamp or similar, which'll force the other one out.

I won't recommend re-using the seals, but I always have done.

Haha, cheers Sam, good tip.

Tried re-setting and bleeding them today and in true noob style...failed. I was pumping the brake (to bleed it) with the diaphragm in - and as this was all drawn out when I checked the fluid (from partial vacuum I assume?) I don't think I was meant to replace it before bleeding...

SO. Hopefully after tomorrows attempt I get it right and pump the pistons out... Unfortunately I ordered some new seals before I got to your post - so might as well wait a few days before re-assembling.

Short version, I spray them with aerosol brake cleaner, red rubber grease on the seals and then push the pistons back in. Clean of excess rubber grease, fit new pads with a smear of copper grease on the back and re-assemble.
Bleed them and then put a cable tie around grip and brake lever to maintain pressure and ensure no hydraulic leaks.
That's just me maybe.

Originally Posted by sam anon

I won't recommend re-using the seals, but I always have done.

Originally Posted by sp07tjwh

Haha, cheers Sam, good tip.

Unfortunately I ordered some new seals before I got to your post - so might as well wait a few days before re-assembling.

That's not a bad thing. I always try to re-use the seals, but truth of the matter is, you can never guarantee they are going to be reusable once removed. It would be a bit of a bugger if you stripped the calipers with the aim of using the old seals and found they were beyond use. With no spare seals to insert, job would come to a grinding halt.

I always buy a set of seals, if they don't get used then they sit on the shelf for the time when they are needed.

I got mine out before using a cablie tie round the piston and then pole grips on that, tip from YC.

Long version, I have 2 sets of front calipers, one set on the bike and one serviced and ready to fit.
My spare set are from my curvy.
I just need a spare rear caliper.

Af'noon again all.

Got them out by bleeding/pumping brakes till one came out - serviced (with new seals, they arrived this morning), re-attached with serviced piston clamped and repeat. Worked a treat even if I did have to bleed my bike a dozen times overall.

Thanks for the input everyone - got to do some more bleeding tomorrow to stiffen them up a touch but all good otherwise!

Well done, nothing like learning new skills and putting them to use successfully!

Originally Posted by sam anon

Well done, nothing like learning new skills and putting them to use successfully!

And more importantly, money kept in the pocket instead of handing it over to someone else to do the job.