Freeing off seized disc brakes (hope hydrolic)

[trxrincon]

Hey I've just bought a bike that has seized ( Hope hydrolic) brakes both front and back. Any suggestions on how I can free them off so I can ride it? cheers Rob

 

[cyfa2809]

Undo caliper bolts and push the bike?

Mayb put something between caliper and fork/frame so they dont mark.

 

[old_coyote_pedaller]

Open each bleed nipple a little bit. Use a rag to catch the fluid that will come out. I've had this happen to old Hope XC4 hydraulic brakes when the bike was left for long periods in the hut during winter. I think because the brake fluid is hygroscopic it absorbs enough moisture to push out the pistons because the XC4's are a closed system.
On the other hand the pistons might be seized in the calipers, a dismantle, clean up, new seals and change of fluid should get them working OK.

 

[Pfennig]

As Old Coyote says, drain a small amount of the fluid and they should free up. If that doesn't work, you can unbolt the two halves of the caliper to take the calipers off the bike before having some 'fun' trying to free off the siezed pistons

 

[EarlofBarnet]

I struggled with a set of Mono M4's that had a couple of seized pistons. No access to the rear of the pistons that had seized. Hope do a caliper refurb for £40 ish that includes fitting new pistons, seals, pads etc.

 

[trxrincon]

Some really handy replys there thanks, I've just been to the shed and sprayed some disc cleaner on them and I've got the wheels to turn but they bind like mad!

 

[BerthaPog]

My Hope minis suffer with this is left to stand. Quick fix is to remove the wheels, force the pads back with a large flat blade, and get them moving again. Proper fix is proberbly to replace the pistons, which can build a "stuck" position with build up of crap around the piston - think Hope changed the piston material to metal at some point?

 

[dbmtb]

Hope changed piston material from metal to phenolic (kind of plastic) to reduce seizing.

The brakes I've had that seized and that I couldn't fix by removing the pads, dripping DOT oil on the pistons and "massaging" back and forth until they ran smoothly all turned out to have damaged (worn) pistons.

If they are monos, and without a compressor they are a nightmare to strip down.

 

[bigmick]

my adaptor on here http://www.retrobike.co.uk/forum/viewto ... 6&start=30
might give you the option of fitting any is caliper if you cant unseize them