Rear Master Cylinder

After an extensive spring upgrade blitz, all that is left are new SS brake lines, which should be here any day. When the sun finally popped out on Friday, couldn't resist the temptation to slap on the old lines temporarily, as I have speed bleeders on all calipers, and brake fluid changes are a snap.

Could not get the rear brakes working properly, and tore apart rear master to find a cracked piston seal. On further investigation, these cup seals, or the piston assembly is no longer available for my '78 KZ650 C2.

I have posted an ad in the classifieds for a rear master, but I don't really need the whole works, just the cup seal for the piston.

Has anyone ever checked with seal or hydraulic shops to find a replacement cup seal for the piston? How about a master from a different bike? There are different places with master re-build kits, but not many I could find for the rear of the 650. I used a kit for a 1000 to re-build my front, but am having trouble locating one for the rear. Kawasaki.com shows part #'s 43020-1004 or 43020-1007 for the piston w/seal, but no longer available .
Any suggestions greatly appreciated, as this is the last holdup before pure, un-adulterated riding fun . Even worse, my wife and son are gone for the weekend, and I could have had 4 days torturing the odometer .:lol: . Thanks.

Try Z Power, they've got a good range of brake bits.

I have a good working rear cylinder. I replaced mine with gsxr rearsets and had to cut the mounts off of the frame to get the rearsets to fit, so I will never put the origional back on the bike. U2U me if you want it, I am VERY reasonable.

Post edited by: HENRYJ, at: 2006/05/16 11:15

Thanks, Henry. U2U sent.

Dave

I am also trying to resolve the same issue - leaking fluid and sucking in air through the seals on the rear master cylinder of a KZ650C2.

I've read a few threads with the same trouble - no rebuild kits for these master cylinders.

Does anyone know if there's a quick replacement for the rubber seal on the piston and the rubber cup? Certainly these parts are not specific to the C2, and many master cylinder rebuild kits have rubber seals and cups that look exactly the same.

I'm trying to attach a picture of my KZ650C2 Rear Master Cylinder dismantled for cleaning.

Post edited by: inline79, at: 2006/05/30 22:36

looks about the same as kz 1000 rear mastercylinder,have you compared the 2?

I do not have a KZ1000 rear master cylinder to compare it with, but if someone out there has measurements of the two it would really help me stop my leaking brake fluid.

I am having the same trouble. All I am lookig for now is any master cylinder that has the mounting holes 2" apart. ZX6 and the like will work and you will be able to get rebuild parts.

I am having the same trouble. All I am lookig for now is any master cylinder that has the mounting holes 2" apart. ZX6 and the like will work and you will be able to get rebuild parts.

I just went thru the rear master cyl on my ltd1000, looks just like what you have, parts are aval from z1, seems like it was around 60 bucks for a kit. one thing I am still having bleading issues, cant seem to get all the air out

To bring this thread to a close I wanted to update that I took my master cylinder apart again, found the cup seals and piston seals intact, but the inside of the cylinder itself slightly corroded. After a lot of emery-clothing and some filing at corrosion, my rear master cylinder no longer leaks. Now the challenge is getting all the air out of the system.

inline79 wrote:

I'm trying to attach a picture of my KZ650C2 Rear Master Cylinder dismantled for cleaning.

How did you get the resevoir apart? It looks very much like my front master cylinder which I couldn't get apart. I need to disassemble and clean both my master cylinders. I was able to change out the fluid in the front, but the fluid in the rear is over 10 years old.

Thanks.