Hope XC4 piston removal

[Ruby900turbo]

Hi,

Any tips on taking out the pistons on old Hope XC4's? Calipers are split in half already. Looked on the Hope website and it says use a pump whilst holding your finger over the fluid hole but mine are not budging. Any secret methods or tips?

Cheers, James.

 

[elPedro666]

Compressor?

If you only take on tip, make it this one: KEEP OUT OF THE WAY! When it pops free you'll need to catch it in something, I'd suggest not the gut

 

[valve bouncer]

Use a track pump with a little 40mm or so piece of tubing between the pump and the hose hole. Seal it all using your fingers and get someone to pump like mad. They'll come out.

 

[elPedro666]

They probably will - but you won't believe at what velocity

 

[Ruby900turbo]

Hi,
Thanks for the tips. Do they need to be turned as I pump them out? I presume they come out together? Or if one comes out first is there an obvious way to blank off the removed pistons oil feed hole? I have never seen inside one so not sure what to expect. Will try and remove them this weekend and will let you know how I get on.

Cheers, James.

 

[valve bouncer]

Yeah one will probably come out before the other but you might get lucky. Then it gets difficult but it can be done. Get someone to give you a hand but your thumb makes a good seal for the caliper body when one piston is out. Other hand keeps the track pump and tube in place and your third hand pumps away! I'm a complete novice at this and I could completely rebuild my E4s (also twin piston) to my satisfaction so if I can do it anyone can.

 

[bren]

Grease gun is a more predictable and less ballistic way of removing them but it works best when the caliper is whole, use blocks/wedges to stop the free moving ones from coming out before the most stuck one budges.
Once they're all out virtually simultaneously you just clean it up once it's apart with aerosol brake cleaner.

 

[Ruby900turbo]

Thanks again for all replies guys. The whole world of building, riding and fixing bikes would be so much easier without ill 3 1/2 year old twins, a job that involves driving from London to Aberdeen via the Lakes and Glossop in between, and no time to indulge in important piston pushing. Thanks for the grease approach but gun is in Dundee whilst I won't be there soon. Grease sounds good though compared to pneumatic disembowelment...

Cheers, James.