Anyone rebuilt Hope brake calipers?

[lufbramatt]

Am currently rebuilding my old Orange Evo2 hardtail which has Hope Mono Mini disc brakes on it. The last few times I used it the brakes were dragging a bit, a bleed didn't sort it, and the pistons seem a bit sticky in the bores which is stopping them retracting properly. Just seen I can get 2x seal kits, new pistons and the splined tool to take the calipers apart for <£20 all in on Chain Reaction.

Anyone had any experience taking these apart? I've rebuilt car brake calipers before so assuming these will be similar just a bit smaller....

Edited by lufbramatt on Wednesday 6th April 14:06

[Tiddy1]

yes they are very much like car calipers and very easy to re-build, however I have found that even after a seal rebuild they are often not great, the older brakes suffer from corrosion of the pistons and calipers and once the anodizing is knackered new seals wont do you much good. Take the pads out and have a look where the pistons exit the calipers and the state of the exposed piston, if it is badly corroded then new pistons are the only option. Dose the kit come with new pistons or just the seals?

An air line is handy for blowing the pistons out of the calipers

Simon

[lufbramatt]

Yeah mine are a few years old, from 2004 IIRC and have the metal pistons. The seal kits are £4 per caliper and the pistons are about £4.50 each for the updated phenolic resin ones so its hardly breaking the bank to just order the whole lot, saves taking it to bits twice.

[Watchman]

Haven't rebuilt Hope calipers but I have stripped/cleaned/reassembled Shimanos (2 different types), SRAM (1 type) and Tektro (two types) with no issues. If I can't pull the pistons out easily, I just use my stirrup pump to blow the pistons out using a bleed nipple in the caliper if one isn't standard fit (it was on the Tektros and SRAM but not on the Shimanos).

On one of the Shimanos, the pistons looked corroded on the sides. I wondered if they may not have been stainless steel but they were not attracted by a magnet so they must have been. I gently re-faced them with some very fine grit paper, and reused them with the existing seals. They're still working OK 2 years later - not binding or leaking - although they don't get used much in the rain since I've superceded the bike with another so I don't know how they'd fare with regard to corrosion if I did use them "wet".