front brake bleeding

[Dookbob]

I,m having a hell of a job to bleed the front brake on my KZ1000B1, it,s a 1977 ex USA model. it was working fine before I stripped the bike to restore it. After fitting all new brake pipes ( twin disc ) I cleaned up the calipers, checked out the movement of the pistons etc,. then filled the master cylinder reservoir and started to bleed the system. I got nowhere with that, so i tried every trick in the book, at least every trick that i am familier with. Back feeding fluid from a syringe through the bleed nipples, then a vacuum gadget that is supposed to pull the fluid through the system without having to pump the brake lever. Stripped the master cylinder next, cleaned the whole thing out , blown through with compressed air then replaced everything soaked in clean brake fluid, this made no difference. All I can think of now is that there could be a blockage in the port that feeds fluid from the reservoir to the seal chamber. Does the plastic reservoir detach from the metal part of the rest of it? I dont want to start tugging at it untill I know that it will actually come off, I cant tell if it is on a thread or is it bonded in. I would apreciate any advice before I buy a new master cylinder.

[PAULJAC47]

Use mole grips with protectors or pipe clamps to compress outlet from mc and see if you get pressure,if so do same trick on each caliper hose inlet,this will let you know what is happening,air or component,Zed brakes are a pain!

[jimmock]

SPLIT BLEEDING!!!

Bleed to the banjo on the outlet of MC.

Then bleed to the splitter.

Then bleed to ONE caliper.

Then bleed the other caliper.

You should get a result with that method.

[z1bman]

the plastic chamber unscrews from the main body there is no need to remove this if you are clearing the bleed hole just use a bristle from a wire brush

[nigel bessant]

Cable tie the lever to the handle bar and fill the reservoir. Cover it and leave it for a week, checking the level occasionally. Self bleeds. Sounds ridiculous but it works.

[Dookbob]

the plastic chamber unscrews from the main body there is no need to remove this if you are clearing the bleed hole just use a bristle from a wire brush

I looked in the reservoir for a bleed hole to poke at, but there are two plastic discs in the bottom of the reservoir, and they dont come out, thats why I am enquiring about the possibility of removing the plastic part, to access the supply and release ports ( hopefully)

[Dookbob]

Cable tie the lever to the handle bar and fill the reservoir. Cover it and leave it for a week, checking the level occasionally. Self bleeds. Sounds ridiculous but it works.

I,m assuming that I would need to open a bleed nipple too in order for this method to work?

[Dookbob]

SPLIT BLEEDING!!!

Bleed to the banjo on the outlet of MC.

Then bleed to the splitter.

Then bleed to ONE caliper.

Then bleed the other caliper.

You should get a result with that method.

I tried that , but couldn,t get fluid to discharge from the MC

[nigel bessant]

Cable tie the lever to the handle bar and fill the reservoir. Cover it and leave it for a week, checking the level occasionally. Self bleeds. Sounds ridiculous but it works.

I,m assuming that I would need to open a bleed nipple too in order for this method to work?

Nope, the air works it way back up to the master cylinder. When I said a week.......it might be a bit longer

[jimmock]

SPLIT BLEEDING!!!

Bleed to the banjo on the outlet of MC.

Then bleed to the splitter.

Then bleed to ONE caliper.

Then bleed the other caliper.

You should get a result with that method.

I tried that , but couldn,t get fluid to discharge from the MC

Sounds like you have a MC fault???