Juciy 7 Pad fitment - new caliper :-(
Discussion
Hi - I just tried to change the rear pads on my juicy 7's. Adjusted the pads gap, used a screwdriver to level open old pads, removed old pads and couldnt get the new ones (trying both avids and some cheaper ones) to go in. Eventually I pushed too hard and I have snapped one of the pistons off ! So I guess that is new caliper time? aggghhh
Avid spares are notoriously expensive.
CRC sell a rebuild caliper kit which is all of two pistons, 3 small bolts, a tiny rubber ring and a banjo bolt for a chunk of cash.
But... If you just broken the 'nipple' from the centre of the piston off I wouldn't lose any sleep over it, they're quite thick and won't leak and given how bloody tight the pads are it's not like they're gonna slip.
If you do choose to rebuild - my top tip. Remove the 3 bolts that hold the caliper together (not the one the fluid runs through). Very slightly loosen the last bolt (6mm socket I think), try not to loose any fluid. Spin one of the halves 180 with the hose pointing between them. Then pump the lever, if one piston moves quicker than the other squeeze it to let the other one catch up. Eventually one with pop out (dumping fluid everywhere - so put some paper down) and the other should come out with little effort.
They're murder to get out otherwise.
CRC sell a rebuild caliper kit which is all of two pistons, 3 small bolts, a tiny rubber ring and a banjo bolt for a chunk of cash.
But... If you just broken the 'nipple' from the centre of the piston off I wouldn't lose any sleep over it, they're quite thick and won't leak and given how bloody tight the pads are it's not like they're gonna slip.
If you do choose to rebuild - my top tip. Remove the 3 bolts that hold the caliper together (not the one the fluid runs through). Very slightly loosen the last bolt (6mm socket I think), try not to loose any fluid. Spin one of the halves 180 with the hose pointing between them. Then pump the lever, if one piston moves quicker than the other squeeze it to let the other one catch up. Eventually one with pop out (dumping fluid everywhere - so put some paper down) and the other should come out with little effort.
They're murder to get out otherwise.
http://www.chainreactioncycles.com/Models.aspx?Mod...
Thanks - this CRC kit looks well priced compared to others. I already have a bleed kit somewhere. So I might buy one and see how I get on. otherwise look out for a cheap replacement caliper on ebay. There is a pair of new ones for £169 on ebay now.
Thanks - this CRC kit looks well priced compared to others. I already have a bleed kit somewhere. So I might buy one and see how I get on. otherwise look out for a cheap replacement caliper on ebay. There is a pair of new ones for £169 on ebay now.
What you need is an Avid pressure foot kit. This contains a new piston and piston seal as well as a new O-ring to go between the caliper halfs as you will need to split the caliper to replace the piston. I had a quick look and found them here http://www.jejamescycles.co.uk/avid-juicy-pressure... That pic shows two pistons but I think each kit only has one, it has been a while since I ordered one though so I could be wrong. If you do need two I would phone them and find out for sure if a kit has one or two pistons in it.
Some tips for fitting. The old piston can be a total nightmare to get out. I have had to drill holes in pistons and hit them with a sharp object to crack the piston into a few pieces before it would come out, they are ceramic rather then metalic though so they will break with a sharp blow and most likely not harm the caliper body. If the brake is still together then you can pump the piston out before you take the calpier apart. This will avoid a lot of bother and is easy to do, especialy if only replacing one piston.
When putting the new piston in be carefull not to damage the new seal, I have done this before as its easy to tear it when pushing the piston into place. Cover the seal and outside of the caliper in DOT4 or 5.1 fluid when you are installing as this will reduce the friction between them and allow it to slip in there a bit easier.
You will need a bleed kit to bleed the system once you have replaced the piston though, if you don't have one you can bodge one together, there are probably instructions online as to how to do this however it might be easier to just buy one. Plus you can then bleed your brakes every year or before an alpine holiday etc.
Some tips for fitting. The old piston can be a total nightmare to get out. I have had to drill holes in pistons and hit them with a sharp object to crack the piston into a few pieces before it would come out, they are ceramic rather then metalic though so they will break with a sharp blow and most likely not harm the caliper body. If the brake is still together then you can pump the piston out before you take the calpier apart. This will avoid a lot of bother and is easy to do, especialy if only replacing one piston.
When putting the new piston in be carefull not to damage the new seal, I have done this before as its easy to tear it when pushing the piston into place. Cover the seal and outside of the caliper in DOT4 or 5.1 fluid when you are installing as this will reduce the friction between them and allow it to slip in there a bit easier.
You will need a bleed kit to bleed the system once you have replaced the piston though, if you don't have one you can bodge one together, there are probably instructions online as to how to do this however it might be easier to just buy one. Plus you can then bleed your brakes every year or before an alpine holiday etc.
The nipple you knocked off helps stop the pads falling out. If you've still got the spring clip on top of the calliper then you shouldn't worry about it. I've got some spare Juicy Ultimate callipers on eBay at the moment but you shouldn't need to replace or repair.
With the pads out give the calliper a good scrubbing and clean. Then spray some silicone oil/grease onto the pistons. Allow to penitrate. Then CAREFULLY pump the brake lever to move the pistons out a bit. Spray with silicone again. Allow to penitrate and then lever the pistons back into the calliper body. I use a metal tyre lever but a LARGE flat bladed screwdriver will do.
ETA; I've also got half a calliper rebuild kit (1 piston and new seals) if you really feel the need to rebuild.
With the pads out give the calliper a good scrubbing and clean. Then spray some silicone oil/grease onto the pistons. Allow to penitrate. Then CAREFULLY pump the brake lever to move the pistons out a bit. Spray with silicone again. Allow to penitrate and then lever the pistons back into the calliper body. I use a metal tyre lever but a LARGE flat bladed screwdriver will do.
ETA; I've also got half a calliper rebuild kit (1 piston and new seals) if you really feel the need to rebuild.
Edited by mk1fan on Monday 29th March 14:46
Sorted ! Been away on hols but got my local bike man to:-
1) Pick up the bike
2) Fix it
3) Road test
4) deliver it back
to fix it he had to buy a service kit, take it apart (so siezed he had to use a drill etc), strip, rebuild, bleed twice etc....
The service kit was £10, the fluid etc £5 and the labour £10. £25 ! I am happy with that !
1) Pick up the bike
2) Fix it
3) Road test
4) deliver it back
to fix it he had to buy a service kit, take it apart (so siezed he had to use a drill etc), strip, rebuild, bleed twice etc....
The service kit was £10, the fluid etc £5 and the labour £10. £25 ! I am happy with that !
Floor Tom said:
What you need is an Avid pressure foot kit. This contains a new piston and piston seal as well as a new O-ring to go between the caliper halfs as you will need to split the caliper to replace the piston. I had a quick look and found them here http://www.jejamescycles.co.uk/avid-juicy-pressure... That pic shows two pistons but I think each kit only has one, it has been a while since I ordered one though so I could be wrong. If you do need two I would phone them and find out for sure if a kit has one or two pistons in it.
Some tips for fitting. The old piston can be a total nightmare to get out. I have had to drill holes in pistons and hit them with a sharp object to crack the piston into a few pieces before it would come out, they are ceramic rather then metalic though so they will break with a sharp blow and most likely not harm the caliper body. If the brake is still together then you can pump the piston out before you take the calpier apart. This will avoid a lot of bother and is easy to do, especialy if only replacing one piston.
When putting the new piston in be carefull not to damage the new seal, I have done this before as its easy to tear it when pushing the piston into place. Cover the seal and outside of the caliper in DOT4 or 5.1 fluid when you are installing as this will reduce the friction between them and allow it to slip in there a bit easier.
You will need a bleed kit to bleed the system once you have replaced the piston though, if you don't have one you can bodge one together, there are probably instructions online as to how to do this however it might be easier to just buy one. Plus you can then bleed your brakes every year or before an alpine holiday etc.
Spot on re what was required re parts and breaking the old piston! Although per my last post managed to get this all done for me by the local bike guy!Some tips for fitting. The old piston can be a total nightmare to get out. I have had to drill holes in pistons and hit them with a sharp object to crack the piston into a few pieces before it would come out, they are ceramic rather then metalic though so they will break with a sharp blow and most likely not harm the caliper body. If the brake is still together then you can pump the piston out before you take the calpier apart. This will avoid a lot of bother and is easy to do, especialy if only replacing one piston.
When putting the new piston in be carefull not to damage the new seal, I have done this before as its easy to tear it when pushing the piston into place. Cover the seal and outside of the caliper in DOT4 or 5.1 fluid when you are installing as this will reduce the friction between them and allow it to slip in there a bit easier.
You will need a bleed kit to bleed the system once you have replaced the piston though, if you don't have one you can bodge one together, there are probably instructions online as to how to do this however it might be easier to just buy one. Plus you can then bleed your brakes every year or before an alpine holiday etc.
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