Replacement disk calippers

[Yellow Fang]

I think I need some replacement calippers for my front disk brake. The pistons just lock and don't release. I've bled the brakes and I am sure it's not that. The problem is that I don't think I can get the original calippers any more. Will most calippers work? What do I need to know? The disk brakes are Hope, but I don't know the model.

 

[the snail]

You'll need to match the slave cylinder size to the master cylinder. If you can find out what model they are, talking to hope might be best, they were very helpful when I called them.

 

[ColinJ]

I think I need some replacement calippers for my front disk brake. The pistons just lock and don't release. I've bled the brakes and I am sure it's not that. The problem is that I don't think I can get the original calippers any more. Will most calippers work? What do I need to know? The disk brakes are Hope, but I don't know the model.

Do they lock all the time or just after a long descent? And are the brakes the closed system type that had dials on top of the brake lever mechanisms? I have Hope C2 on my old mountain bike and the brake fluid expands when it gets hot. You have to turn the dials to back off the pads otherwise the brakes can lock on until the fluid cools down. It is a bit of a pain but I got used to doing it with my thumb when descending. The problem came when I forgot to adjust them back again because the cold brakes then did nothing - that caused a few scary moments!

 

[Yellow Fang]

They've deteriorated, so they're locked all the time now. I can't see any dials.

 

[ColinJ]

Ah, the dials are chunky and obvious so you don't have that type!

 

[iluvmybike]

Do they lock all the time or just after a long descent? And are the brakes the closed system type that had dials on top of the brake lever mechanisms? I have Hope C2 on my old mountain bike and the brake fluid expands when it gets hot. You have to turn the dials to back off the pads otherwise the brakes can lock on until the fluid cools down. It is a bit of a pain but I got used to doing it with my thumb when descending. The problem came when I forgot to adjust them back again because the cold brakes then did nothing - that caused a few scary moments!

That Hope C2 design is ancient technology now as it was a totally closed system. All modern brakes allow room for expansion with a rubber diaphragm inside the lever.

I think I need some replacement calippers for my front disk brake. The pistons just lock and don't release. I've bled the brakes and I am sure it's not that. The problem is that I don't think I can get the original calippers any more. Will most calippers work? What do I need to know? The disk brakes are Hope, but I don't know the model.

What make of brake are they. Hope & Formual calipers can be rebuilt with new seals and pistons. If they are Avids chuck them in the bin - they seem to have a preponderance for sticking firmly especially if not used for some time. Shimano - could be rebuilt but they don't seem to supply spares kits..

 

[ColinJ]

That Hope C2 design is ancient technology now as it was a totally closed system. All modern brakes allow room for expansion with a rubber diaphragm inside the lever.

Indeed - early 2000s, in my case! It only took me one ride with a couple of decent descents back-to-back to discover the shortcomings of the design...

First descent, brakes start to heat up, begin to lock on, back off with the dials, all ok... Immediately another big climb, over the summit, then hurl myself down the next descent... Not too technical, build up speed, tight technical bend coming up rapidly, apply brakes, levers pull to bars, no braking... FARRRRRRRRRRRRRK!!!!!!!!!!!!!!!!!!!!!! (A frantic readjustment of the dials restored brake function with one second to spare!)

It's a pity because otherwise they were nice brakes. They are still on the bike, but not for long now - my cousin donated more modern brakes to me which I will fit some time soon. I'll probably offer to donate the old C2s to somebody on the forum who won't be doing the kind of descents that lead to the overheating problem. (ANYBODY INTERESTED? NB I eventually wore out one of the dials, so that would need replacing.)

 

[Mark pallister]

I think I need some replacement calippers for my front disk brake. The pistons just lock and don't release. I've bled the brakes and I am sure it's not that. The problem is that I don't think I can get the original calippers any more. Will most calippers work? What do I need to know? The disk brakes are Hope, but I don't know the model.

Contact hope ,there customer service is excellent

 

[ChrisEyles]

Are the piston surfaces nice and clean?

I had a problem with my tektro auriga calipers a while ago where one piston was very reluctant to retract. On inspection the piston surface was quite dirty and this was impeding the movement of the piston back into the caliper through the seal.

I squired in a bit of GT85 and used a bit of cotton thread to "floss" the surface of the piston, then used a small screwdriver between the pistons to lever them apart, forcing the piston back into the caliper.

Had to iterate pumping the brake lever to move the piston back out, give it a clean, force it back in several times to get it working properly, it was a bit of a faff. But since I did that it's been working perfectly for quite some time now.

Might be worth a go?