Weird Rear Master Cylinder Problem

This will be a tough one for me to describe. But I'll do my best. Not getting ANY brake fluid from the reservoir to the brake line (Banjo Bolt)area on the Master Cylinder. It's as if a hole is plugged up or blocked. Took Master Cylinder off bike - poured brake fluid in the reservoir and hand pumped the piston. You can feel and hear the air being pushed through the brake line opening in the master cylinder when I pump the piston, but no fluid coming out. It's as if the fluid is not draining into the cavity or area that would allow the piston to push the fluid out of the brake line opening. There are two small holes at the bottom of the reservoir area in the master cylinder. And of course a hole in the brake line cavity of the master cylinder. Again, air pushes out of the hole in the brake line cavity when I pump the piston, but no brake fluid from the reservoir. Any ideas what could be causing this? This is a 1976 KZ900LTD. Your ideas are appreciated.

pictures!

if you put the piston and cup in the way it shows in the diagram id say you need to benchbleed the mastercylinder seperate from rest of brake system.put mastercylinder back on bike hook up brake pedal.hold your finger over the hole on mastercylinder where brake line goes and pump pedal a couple of times,hold brake pedal down and take your finger off the hole.(your using dot5 brake fluid so it wont hurt your paint)put your finger back over hole and pump it again just like youre bleeding the brakes see if this helps it might take a while to get the air from mastercylinder then hook up your brake line and bleed the rest of your system.id go ahead and fill front mastercylinder and crack bleeder valves open and let it gravity bleed for a while to get fluid to calipers this will save headaches later.give it a try!if it dont work ya know the #:whistle:

Good News! Real BAD News :pinch:
Good news is wiremans Bench Bleed suggestion worked. Fluid is pumping out in great gobs! Bad news, I discovered that one of my beautiful rebuilt front calipers is stripped and buggered where the piping fitting (banjo bolt area) is threaded. I believe the caliper could still be used if I did away with the piping and just custom built banjo to banjo brake lines using a banjo bolt instead of the pipe. If I use the s-piping, then I think I would have to have a new caliper as the hole that the piping fits over, is splayed open - causing fluid to leak back out over the fitting. Any experience or recommendations? And no...I don't think I buggered it up. I'll blame it on the bead-blast/powdercoat guy since he's not around to defend himself....:whistle:

Caution: If you are a lover of calipers, this graphic picture may not be suitable for viewing!

oh my:sick: ill box a replacement up and ship it out,which side is it?:whistle:

wireman wrote:

oh my:sick: ill box a replacement up and ship it out,which side is it?:whistle:

Wireman to the rescue! Now that's service!

Good job, dude....

Pterosaur wrote:

wireman wrote:

oh my:sick: ill box a replacement up and ship it out,which side is it?:whistle:

Wireman to the rescue!

Now that's service!

Good job, dude....

hey,i like it!this could be a new look for me:Pnow if i couldget him to answer one of his phones!:S

Post edited by: wireman, at: 2006/07/04 14:34

Geez it even looks like him. Thanks Wireman.