master cylinder probs

[mick znone]

guys, Ive just fitted the front caliper, no problem. bleeding it=problem. fluid will not pump through the system. the hose down from the master cylinder to the caliper no problem, blows through. master cylinder off bike,on the table, put fluid in, pump and nothing goes through. ?????? two holes in master cylinder, one jet size [bubbles come out] one bigger and you can see movement inside as you pump the lever.

its a single disc front brake on a z1a and it worked fine before i touched it do i need to strip the master cylinder and buy a kit ?

have a week off and feel a bit like all work and no play makes z a dull bike, to be honest

[Ginger Bear]

Mick,
Bleading these from empty can be a b*stard of a job.
It is possible to buy vacuum devices that suck the fluid through the system. I believe you can replicate this quite cheaply with a syringe & a bit of hose.
Method; Connect hose (this must be an airtight fit) to the blead nipple & undo by 1/4 of a turn, then connect syringe to the hose, again it must be airtight.
As you pull the plunger out of the syringe it will create a vacuum & suck the fluid through. Once you have the system full of fluid, you can finish off bleading as normal. It would also help to remove the nipple first & coat the thread with grease to stop air being pulled in when you suck the fluid through.
If you are not already I would reccomend using DOT 5.1 fluid, as I believe this doesn't have the paint removing properties of the old stuff & a can of brake cleaner.... fantastic stuff, will rinse off any spilt fluid..... Good Luck!

[Reecy]

Mick,

All that Bear has said is good advice

I had the same problem that you are having last weekon my Z1000

I have two bits of advice to take account of on top of what bear has said:---

the problem i found on my bike was with ar trapped in the bend in the brake switch connector (fitted to the bottom yoke) which points upward when it is fitted on the bike and traps air which you can't bleed away-no matter how much you syringe fluid up and down the system.

(I find using the syringes are great to carryout general brake bleeding or if you are just replacing the fluid)

The solution was to un bolt the brake switch connector and force the bend section to point skywardsand then raise the caliper above the switch connector, this way the air travels up the pipe to the caliper bleed nipple where you can bleed it away.

Try it -i hope it works for you

Reecy

[zedrider]

my mate showed me this rather neat trick bleed the system back wards in outher words . from the cliper . undo the master cylinder cap fit pipe with a syringe ( full of fluid ) and good fitting pipe to the bleed nipple open the nipple a little and push the fluid in . works a treat and in half the time . hope it works for you as it did for me . ps keep an eye on the master cyclinder so it dosent over flow .

[mick znone]

guys, thanks very much, job done, cant honestly say how, ive spun out a bit over the bike this evening, but i have a front brake now. i could not get the fluid to pump through the master cylinder, then whilst sitting waiting for a coffee to arrive, i put my thumb over the open end of the master cylinder and fluid sprayed out everywhere. brains fried at the moment but im sure it will make sense tomorrow.

[Steve R]

Mick, I am going to be doing this tomorrow as I have a new splitter to fit, that I have been polishing today.

When you say thumb over open end of master cylinder, where exactly do you mean?

Also when zed and other are talking about using a syringe, how big? and where do you buy one?

[Ginger Bear]

Mick, I am going to be doing this tomorrow as I have a new splitter to fit, that I have been polishing today.

When you say thumb over open end of master cylinder, where exactly do you mean?

Also when zed and other are talking about using a syringe, how big? and where do you buy one?

Try this http://cgi.ebay.co.uk/BRAKE-BLEED-KIT-F ... 240%3A1318

[mick znone]

OK Steve, i couldn't get the fluid to pump down the system after fitting the rebuilt caliper. i took the master cylinder off, blew down the hose on the bike and it was clear.i put some fluid in the master then pumped, not a lot happened, then i put a thumb over the hole where the bolt from the hose was and it sprayed out like a power hose. then i put it back on the bike and connected up. i think i then pumped it with the bleed nipple closed for a few pumps, then i bled as normal. you have to be careful because the air traveling back up the system bubbles the fluid over the edge of the bowl, i put sheets over everything,then i put the rubber cap from the lid on the master bowl and that stopped it from squirting. i think the syringe method might be easier. i imagine you connect a syringe [large, not junkey size] to the bleed hose coming off the bleed nipple and draw it through.

[Steve R]

Thanks GB, I really want to do this tomorrow if possible.

Just to be 100% clear Mick, you had the hose off the master cylinder and put your thumb over where the hose would normally go? If this is hte case I guess with the air in the system the master cylinder was not priming, but when you had your finger over the hole where the hose went it created a vacumm for the master cylinder to prime against.

Thanks for the prompt replies!

[Rich]

Use the banjo bolts as bleed nipples and just crack them open a little to get the flow starting.

[PAULJAC47]

I have had issues just the same,but try this, make sure system is full by any of the means already suggested,put bike on side stand turn steering to left to get master cylinder horizontal.then give lever a number of hard slaps letting it spring back.turn steering to central position and repeat then to right repeat then back to left,keep repeating if you put a piece of clingfilm over cylinder you should see bubbles come out.i also cover all paintwork with clingfilm.i know this sound unlikely but worked for me and my mate when all others had failed,be carefull if injecting fluid through bleed nipple do it very carefully and gradually,Good luck Z brakes are a B******.......Cheers PaulJ...

[mick znone]

Thanks GB, I really want to do this tomorrow if possible.

Just to be 100% clear Mick, you had the hose off the master cylinder and put your thumb over where the hose would normally go? If this is hte case I guess with the air in the system the master cylinder was not priming, but when you had your finger over the hole where the hose went it created a vacumm for the master cylinder to prime against.

Thanks for the prompt replies!

sorry Steve, ive been busy today and the site has been painfully slow,thumb over where hose was, that is the case. hope you had success with your brakes today mate.