front brakes

[Septic]

hi guys

My front brakesare realy crap. a few weeks back i fitted some tt
35mm handle bar raisers and a longer brake hose bleed the brakes
all nice n hard So i thought while im here ill take the calipers
of take out the pistons and give them a clean. Put them back on
bleed the brakes... shit no brake after about 3 litres of brake fluid
still shit. So i rang up sherlocks the guy there said to put a elastic
band around the lever and the handle bar grip to let it self bleed over
night. Tried it the next morning and it was alot better but still not as sharp
as they were before i had the pistons out. so.. do you think i shoud try
a service kit or am i going to have to fork out on some new calipers?

 

[Tarka]

If you took the pistons right out you should have fitted new seals before re-assembly.

 

[Mouse]

If the old seals were in good condition I don't really see any reason to change them. Nearly every time I've stripped a caliper I have judged it to be not worth changing the seals - the exceptions were calipers that had been allowed to get into a very sorry state. Just make sure the grooves in the caliper body are totally clean and then coat the seals in a very small amount of red brake grease.

Of course a seal kit isn't very expensive so some people might say change them anyway while the caliper is stripped.

What I'm trying to say is, I doubt the spongey brake is due to a seal problem ... unless there's brake fluid leaking out of the caliper! Try riding the bike for a couple of days then bleeding again - that often helps the air settle out of the system. Or some people say take the caliper off the bike and bleed with it above the level of the master cylinder ... never tried that myself but it sounds logical.

I'm sure it'll just be air trapped somewhere.