HELP! Have i knackered my master cylinder?

Forum rules
Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
amorti
Regular Member
Posts: 957
Joined: Sun May 18, 2008 4:51 pm
Bike owned: CB-1, MSX125
Location: Gibraltar

Re: HELP! Have i knackered my master cylinder?

Post by amorti » Fri Jun 17, 2011 7:09 pm

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!!

User avatar
jetblack
Site Supporter
Site Supporter
Posts: 516
Joined: Sat Apr 24, 2010 5:21 pm
Bike owned: '89 NC30 SEED
Location: Nottingham

Re: HELP! Have i knackered my master cylinder?

Post by jetblack » Fri Jun 17, 2011 7:40 pm

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(

zymon
Settled in member
Posts: 43
Joined: Thu Oct 22, 2009 11:17 pm

Re: HELP! Have i knackered my master cylinder?

Post by zymon » Fri Jun 17, 2011 7:44 pm

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 !!!

User avatar
jetblack
Site Supporter
Site Supporter
Posts: 516
Joined: Sat Apr 24, 2010 5:21 pm
Bike owned: '89 NC30 SEED
Location: Nottingham

Re: HELP! Have i knackered my master cylinder?

Post by jetblack » Fri Jun 17, 2011 7:56 pm

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.

User avatar
iDemonix
Site Supporter
Site Supporter
Posts: 651
Joined: Tue Aug 24, 2010 10:26 pm
Bike owned: '92 NC30
Location: Banbury, Oxfordshire

Re: HELP! Have i knackered my master cylinder?

Post by iDemonix » Fri Jun 17, 2011 8:46 pm

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...
A roaring V4 is the summer soundtrack.

User avatar
CMSMJ1
Moderators
Moderators
Posts: 7152
Joined: Thu May 01, 2008 9:42 am
Bike owned: NC30-No9
Location: Chesterfield, United Kingdom

Re: HELP! Have i knackered my master cylinder?

Post by CMSMJ1 » Fri Jun 17, 2011 8:48 pm

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?)
IMPERATOR REX ANGLORUM

The V4 is the law..

NC30 - No9 - my old mate

User avatar
jetblack
Site Supporter
Site Supporter
Posts: 516
Joined: Sat Apr 24, 2010 5:21 pm
Bike owned: '89 NC30 SEED
Location: Nottingham

Re: HELP! Have i knackered my master cylinder?

Post by jetblack » Fri Jun 17, 2011 8:51 pm

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.

Delboy
Site Supporter
Site Supporter
Posts: 836
Joined: Mon May 11, 2009 3:25 pm
Bike owned: NC30

Re: HELP! Have i knackered my master cylinder?

Post by Delboy » Fri Jun 17, 2011 8:51 pm

Are you sure you are doing it right (said the nun to the bishop?)squeeze some more
Fnar fnar :grin:
4 WHEELS MOVE THE BODY 2 WHEELS MOVE THE SOUL

User avatar
CMSMJ1
Moderators
Moderators
Posts: 7152
Joined: Thu May 01, 2008 9:42 am
Bike owned: NC30-No9
Location: Chesterfield, United Kingdom

Re: HELP! Have i knackered my master cylinder?

Post by CMSMJ1 » Fri Jun 17, 2011 8:58 pm

(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
IMPERATOR REX ANGLORUM

The V4 is the law..

NC30 - No9 - my old mate

User avatar
jetblack
Site Supporter
Site Supporter
Posts: 516
Joined: Sat Apr 24, 2010 5:21 pm
Bike owned: '89 NC30 SEED
Location: Nottingham

Re: HELP! Have i knackered my master cylinder?

Post by jetblack » Fri Jun 17, 2011 9:08 pm

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.

Post Reply