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Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 7:09 pm
by amorti
Sounds mad but:
Get a new bit of clear hose. A long bit. Attach it to the bleed nipple. Open bleed nipple. Suck through tube. Stop sucking before brake fluid is ingested!!

Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 7:40 pm
by jetblack
You're right it does sound mad. :0)

Think i'll just get the local mechanic to sort it. Getting to the end of my tether. :0(

Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 7:44 pm
by zymon
thats what i always did-worked for me too :-) tube always sometimes it helps to bleed it at the brake pipes as they meet the master cylinder before bleeding elsewhere - some people on here used to undo the clamp bolts of the master cylinder and tilt it so it lets the air escape before doing the bleeding.

another way is to connect a clear tube on each caliper, crack open the bleed nipple ( left caliper first as its furthest away ) and let it gravity bleed till nice flow is coming out and finish off with a squeeze of b/lever and shutting off nipple , and opening again to bleed like last bit.

dont give up you are nearly there !!!

Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 7:56 pm
by jetblack
but surely when i squeeze the lever it should be forcing the fluid out? i would expect the level in the master cylinder reservoir to go down with each squeeze of the lever as it moves the fluid into the system but the level just remains the same.

when i unsquezeze the lever the fluid n the bleed pipe just goes back to where it was. its like watching a game of tennis. with each squeeze :0(

I've tried gravity bleeding the calipers and fluid is flowing out of them- there is no more air coming out from them, yet i still cant get ay pressure/resistance on the lever.

Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 8:46 pm
by iDemonix
Tried putting a one way valve on the end of the tubing? Can pick up a one-man bleeding kit from Halfrauds for 6 quid that has a pipe with a one way valve on...

Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 8:48 pm
by CMSMJ1
right... close the nipple, squeeze the lever a few times, hold it down and open the nipple. close the nipple, then squeeze some more...then hold it down, then open the nipple.

Are you sure you are doing it right (said the nun to the bishop?)

Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 8:51 pm
by jetblack
idemonix: i've been using the one way valve bleed kit.

Chris, thats the way i'm doing it. but there is literally no resistance/pressure in the lever so pupming it 3/4 times is not different from just pumping it once.

Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 8:51 pm
by Delboy
Are you sure you are doing it right (said the nun to the bishop?)squeeze some more
Fnar fnar :grin:

Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 8:58 pm
by CMSMJ1
(Call me Mark..most people do..(though call me Chris if you really want))

Talk us through it matey - why are we bleeding it? Did you swap lines? Is it bleeding it from totally dry?

You can reverse bleed it - use a syringe and pump the fluid from the bottom bleed nipple til it appears in the res. then do the same for the other line. From there - have a good look over the m/c. Does the action work? Are there any leaks?

It might have a large airlock at the top of it - so take the system off the bike and give it a few taps to dislodge any air.

it is a simple system and so if you have replaced the seal kit and it is all there then there is no real reason it should be such a ballache..

If it was not so wet and I was not already commited to other shit this weekend I would take a razz down and give you a hand. See what goes on next week - if you're still buggered I'll see if I can make it down. Only 30 mins away I reckon.. I've probably got a spare m/c too..wil check

Re: HELP! Have i knackered my master cylinder?

Posted: Fri Jun 17, 2011 9:08 pm
by jetblack
Sorry mate, don't know where i got Chris from!?

A very kind offer from you, which if i cant get it resolved next week i may well badger you for!

I'm bleeding them because the bike is new to me and i wanted to change the fluid. the lever was fine before just a little squidgy.
Started with the bleed nipple on the left(when sat on bike) got about 2 strokes out of the lever when it went soft. Wasn't able to get any fluid moving so figured the m/c seals had gone. Replaced them, problem still persists.

Completely flummoxed.