finally i have a problem!!!

[Carbon_ZX6R]

long time no talk....

well the other week I took the b1h out for a spin
20 of miles in and I realise there is no back pressure on the rear brake , not sure what has happened , but the fluid looks well questionable.
need to know what I need to do to resolve it?
if its strip the calliper id rather replace it , I would say the fluid is contaminated?

any advise given would be appreciated as I need to fix this by the 1st may

[David W]

Have you tried just bleeding it before pulling the caliper apart and probably creating a problem that isn't there?

[PJ]

Agree with DW, bleed it, and use that as an opportunity to get all the old fluid out, which considering that looks like the Brembo style tube instead of a full reservoir shouldn't take long. I can't see any reason to replace the caliper?

When you say no pressure, what do you mean? The pedal goes all the way down without any resistance? Or it's hard as you would expect but you get no braking from the rear?

[Jonesy]

Get rid of the stupid tube and get a proper brake fluid reservoir... That's your problem!

[Manic636]

When I ran that style of tube it was a bigger for allowing condensation to be absorbed into the fluid and needed lots of bleeding and fresh fluid..

[Carbon_ZX6R]

I did bleed it when i put the new line on and it was perfect , never had condensation on my old one , there was the tiniest bit of pressure if i pushed the peddle all the way down but essentially nothing it wouldn't stop a spinning wheel , but was fine before...

[David W]

They are fine for racebikes but don't have a bladder that lets them compensate for pad wear, so you get a vapour lock which prevents new fluid getting into the master cylinder.
Take the stopper out of the top of the tube and give the brake a few slow pumps and I reckon you'll be back in business.

[Carbon_ZX6R]

Nope I tried it , didn't seem to make it any better....

[David W]

Then its possibly got a blockage between the reservoir and the piston thats preventing fluid getting through.

[Carbon_ZX6R]

Then its possibly got a blockage between the reservoir and the piston thats preventing fluid getting through.

so that fluid looks ok to you?


do I just bleed it some more?

[David W]

You said you had no brake pedal pressure?
How are you planning on bleeding it without that?

[Carbon_ZX6R]

You said you had no brake pedal pressure?
How are you planning on bleeding it without that?

Tiny tiny tiny bit if I spin the wheel it will stop it but if your rolling you don't notice it at all

[David W]

Sounds to me like the problem is at the master cylinder end.
It wouldn't surprise me if that stupid garden hosepipe wasn't letting moisture in, and it's corroded the hole through to the master cylinder piston.  It would explain the state of the fluid too.
Those race setups are great for racing but racebikes get new fluid bled through them before every race.

[Carbon_ZX6R]

had one on there before , and never had a problem with it , when this happened it was being stored outside under a cover , right providing that is the problem , what is the procedure?

[David W]

Brake fluid is hygroscopic which means it absorbs water from the atmosphere.  Indoor or outdoor makes no difference.  The water will then sink to the lowest point, corroding things if its left long enough.

Not sure what the answer is.  I'd be tempted to get a big syringe, fill it with fresh fluid and push it back up through the system from the caliper end.  Obviously need to get a pot to catch the stuff coming out of the top.