HELP...HAYES G1 rear brake - NO Pressure

[zoolooter]

Does anyone know if this problem can be fixed? Basically no pressure when the lever is pulled. The bike shop has bled and serviced the caliper, but still the same problem. Any ideas??

I would like to ditch them altogether and use shimano or hope, but nothing will fit. Tried some Hope Mono Pro's but they seem to need a 180 rotor, but the rear rotor cannot go any bigger than a 160 which is on there now.

If theres no solution, it means that my Klein Attitude (that's in perfect nick) is useless because of the 22mm chainstay mount. Very, very frustrating.......

Cheers

 

[hirosawa]

Re:

Something wrong with the seals or piston in the lever? It is ancient by disc brake standards and uses DOT so I would expect the lever to need a service as well as the caliper.

Any sign of leakage on the brake? Did the bike shop change the pistons when they serviced the caliper? They could have caught and damaged a seal putting the pistons back in I guess, I've done it myself many times so it wouldn't surprise me.

If you can still get all the spares, you can fix it. They aren't complex things, as long as everything is free and intact inside and the system seals and holds brake fluid it should work.

 

[zoolooter]

Thanks, for the reply and suggestions. Yes piston changed, gave him the Hayes Caliper Rebuild Kit, I'll ask if he looked at the lever as well. But, as you say they are not complex, also the bike tech had worked in hydraulic engineering for 15 years (so he said), but still coudn't find leaks, air bubbles, etc. Maybe give the capiler to someone else to look at.

 

[jimo746]

There's only a few things it could be really... my 1st thought would be air in the system, next would be a leak either at the lever or caliper end allowing air in or brake fluid out, there should be seals around the master cylinder at the lever, and seals around the pistons in the caliper, any of these could be the culprit.
Or it may be sticky pistons in the caliper?

When you pull the lever how does it feel? does it just go all the way to the bars? or is there some resisitance?
Can you see the pistons pushing out and then retracting as you pull and release the lever? (try taking the brake pads out to better see if the pistons are moving... but don't let them push out so far that they pop out of the caliper!)... you did put the brakepads back in the caliper didn't you? (seen it done before now!).

 

[02gf74]

Sounds like you need new seaks for the lever and my gut feeling is youll struggle to find a set.

Ditch them , dont waste time and miney on it.

A magura marta IS front calliper with an adapter by a2z fits in there with a 160 mn rear disc.
I have such a set up with shimano lever.

Search my post re gary fisher rear brake, u forvet exact title.

Only drawback is some faffing about to bleed it.

 

[Feel no Pain]

Re:

Replace the hose. I used to service a lot of Hayes brakes and this was a common problem.