Z1OwnersClub GB

Well I despair I’ve rebuilt a rear master cyl on a Z1090-A1
with new 5/8” overhaul kit. All orrifices are clean and clear
and when assembled it will not pressurise, in fact I got an old
pipet out and primed it with fluid and when I try to bleed
nothing still bleed nipple.
Is it the same old trick of pushing the rod in and leaving
it for 24hrs, did that for 6 hrs and nothing.
Any tips?

Buy a brake bleed pump kit cost about £12 . This works wonders and you won't go back to the old way of pump a few times and then release bleed nipple . This pulls the fluid through

have you tried pulling the fluid through with a syringe attached to the bleed nipple ?

z1bman wrote:have you tried pulling the fluid through with a syringe attached to the bleed nipple ?

+1 the only way I could get mine to work.

Thanks for advice. I’ve got a vac unit somewhere so will give ir another go

Had the same problem. I removed the banjo at the caliper, finger and thumb over the hole, pump the pedal and you will feel pressure building up , when it does, hold pedal down, release the pressure and repeat several times, the fluid will dribble out, or should, connect the banjo and repeat but using the nipple to release the pressure, fluid will come through, just persivere

I had similar issues with my A2

The key to sorting it involved a vacuum bleeder.
The method that eventually worked for me was:

1 attach the vacuum bleeder to the caliper in the normal way
2 remove the brake line connection to the master cylinder and place in brake fluid container and then draw fluid through the line with the bleed device.
3 using a finger on the side of the master cylinder (Where the line connects to) as a pressure relief valve, pump the cylinder -with the brake pedal- until you have fluid up to that exit point.
4 re connect the (now full of fluid) brake line.
5 bleed in the normal way using the pedal (I found it better if the plastic drain tube from the bleed nipple went 'up' an inch or so before draining down to give a little surplus fluid above the nipple.
This worked for me

see topic called 'Z1000 A2 Rear Brake Master Cylinder' from May 2016

Hi guys

I had the same problem with mine.
The simple solution was to disconnect the brake pedal and bleed it by pushing the rod with your hand.
It turned out that the master cylinder didn't return far enough to enable brake fluid to get into it and pump the fluid in the brake line.
Good luck with it
GrtZ
Philippe

It's funny, on mine I stripped the rear caliper down rebuilt it all and when it came to bleeding it took about 6 pumps and ten mins and the fluid was clear and the pedal was solid, but the fronts I have given up on the lever is spongy and it seems whatever I do it won't improve, so now I just live with it.They can be a real pain in the arse.

Must have the same common issues.
On the front, same here, I noticed the splitter tilts back when bolted on, so could hold an air bubble, I unbolted it straightened it up and bled through, okay now.

mityvac was the only thing that worked for me on my Z1000H when i did a complete strip and refurb of the master cylinder.

Just done my st tonight after a complete rear brake strip down replaced two pistons and seals but z power don't do a master cylinder repair kit for my model so i cleaned up the old one which was gunky , rebuilt it all and used my bleed pump and within 5 minuets the brake was bled and perfect.
Happy days

Some good advice here. I’ll be on it tomorrow
and let you know.

walshyco wrote:It's funny, on mine I stripped the rear caliper down rebuilt it all and when it came to bleeding it took about 6 pumps and ten mins and the fluid was clear and the pedal was solid, but the fronts I have given up on the lever is spongy and it seems whatever I do it won't improve, so now I just live with it.They can be a real pain in the arse.

Try removing the splitter from the steering stem, tilt so there is no back fall for air to trap, cable tie the brake lever over night, should sort it.

DavidZ1R wrote:

walshyco wrote:It's funny, on mine I stripped the rear caliper down rebuilt it all and when it came to bleeding it took about 6 pumps and ten mins and the fluid was clear and the pedal was solid, but the fronts I have given up on the lever is spongy and it seems whatever I do it won't improve, so now I just live with it.They can be a real pain in the arse.

Try removing the splitter from the steering stem, tilt so there is no back fall for air to trap, cable tie the brake lever over night, should sort it.

I will give that a try, I also have an aftermarket splitter on there, which I am gonna replace with a genuine one,I’ll give it a go.