HELP! Have i knackered my master cylinder?

[CMSMJ1]

can you push the pads back on both calipers? All the way? and if so, does the fluid in the res change?

[zymon]

i had exactly the same issue once i first bled my brakes , they trap air summit rotten- have you tried the method i said and let it gravity bleed? ( leave for say 5-10mins open on one nipple, ( keep pot topped right up ) if you see fluid at this point coming out of the tube connected to the nipple close off and repeat for other side . Once again they trap air where the banjos bolt to the master cyl too.

[jetblack]

can you push the pads back on both calipers? All the way? and if so, does the fluid in the res change?

Haven't tried. What will doing this tell me if fluid does flow back into the res?


i tried gravity bleeding and cant seem to get much flow on the fluid, in 5-10 mins i get about 6 drops.

[jetblack]

UPDATE:

After sucking on a piece of aquariam hose connected to the bleed nipples like a 2 dollar whore i've managed to get some pressure into the brake lever and get fluid flowing through both bleed nipples! hooray and thanks for the tip!

However I still have an issue. I can get pressure into the lever if i pump it 10-15 times then i open a bleed nipple, let the fluid flow, close the bleed nipple and then release the lever. at which point the lever has then gone soft again. It takes another 10-15 pumps on the lever before it feels firm again-you can feel it progressively build.

Once firm it seems to hold pressure though so that's something at least!

Any ideas on why its not firm as soon as i've closed the bleed nipple?

[CMSMJ1]

It is not supposed to be firm straight after you close the nipples.. You need to pump it to get all the air out. Sounds like you have had (and still have) an air pocket in it. A few taps on the m/c and keep at it..there is a tech to it and it can be a ballache.

[jetblack]

will a bleed with a vacuum bleeder do the job? I was going to ask the local mechanic to hook it up to his vacuum bleeder to finish it off.

[CMSMJ1]

should do. You can also ziptie the lever back to the bars ovenight - that usually makes the brakes very firm indeed..

[jetblack]

Cool. Ill do that. Ta.