Rebuilding entire braking system KZ1k

Hey guys, I'm new around here, this is my first tech forum post. My full intro is here

Working on transforming my 1981 KZ1000 CSR into a cafe racer, and cleaning up the entire braking system this weekend.

I've removed both master cylinders, and all three calipers from my 81 KZ1000. I've began to refinish the exterior of each.

Both MC's were filled with rusty chocolate mike. No surprise. I sprayed them all out with Honda Brake Cleaner until it ran clear. However even after refilling some with DOT4, the pistons have tightened up terribly. The top diaphragm from the front MC fell apart when hit with brake cleaner.

I assume the seals inside went to shit when blaster with cleaner. So I need 5 rebuild kits and they are on the shopping list from Z1E. However, my Clymers manual has nothing about tearing down the MC's.

The rear MC looks like it has a circlip type deal but I couldn't break even one corner free with a flat head.

Any other ideas on why my MC's tightened up to very worrisome levels? Any clues on how to tear down the front MC or tips on the rear MC circlip?

I will get into the calipers tomorrow.

Here are some pics...





Post edited by: steell, at: 2007/01/06 19:26

Post edited by: sheik*yerbouti, at: 2007/01/08 01:15

do not use petroleum based products on any ruber parts of braking system.

Make sure you clean out the seal grooves in the Calipers with a small screw driver including the boot groove , A white powder builds in there from the brake fluid/water so the new seals wont seat right back in the groove ,Makes it tough to get back together and the Piston will be to tight if you would ,

wireman wrote:

do not use petroleum based products on any ruber parts of braking system.

The Honda brake cleaner i used was perchloroethane and tetrachloroethane and CO2. It said non flammable and no mention of petro. It permanently warped and cracked what looked like a perfect condition, jiggly and rubbery looking good condition diaphragm. Still ate it up... . Had 5 rebuild kits budgeted anyway, I want all the brakes I can get with stock parts plus SS lines and grabby pads.

Oh well anyway I got the front MC totally stripped and the rear i got the circlip off but couldn't easily remove the piston stop and internals...but didn't really try more than just pulling with my hands.

Anyway I got both MC's and front calipers cleaned up with wire wheel, scotchbrite, steel wool combo. I like the vintage look it gives it.

Managed to used 90psi air to blow the pistons out of the calipers, made it real easy. Hopefully have rebuild kits by next weekend wait for SS lines during reassembly.

Pics!







Still got a little inside clean up to do. Using my gun patches and cleaning rod for the bore on the MC was an excellent forum sourced tip...


Just before the letters disappeared... Thought it looked neat, forgot to take a finished pic.


Hey any suggestions on what is safe to clean off this rust with? Some fine steel wool? I can get it off with Brake cleaner and my fingernail, but it would be a lot quicker with an abbrasive, but i don't want to ruin the tolerences on my brake pistons and make leaky calipers.

Piston:




Thanks for the tips Shoe. I'll clean this baby up internally when I've got my rebuild kits and post more pics.

Oh yea one other thing. Once the bike was on the lift, I found out the front wheel with a hard hand spin, wouldn't spin another 1/4 turn when you stopped spinning. TONS of resistance. It was a sticky left front caliper. With the calipers off, a good shove gets you 10 free wheeling spins, so hopefully the wheel bearing will be in usable shape with a good clean and repack.

Later all.

Post edited by: sheik*yerbouti, at: 2007/01/08 00:59

That looks like a great job youve done there, removing the paint.How did you get them so clean?

mark1122 wrote:

That looks like a great job youve done there, removing the paint.How did you get them so clean?

thanks for the encouragement mark, after 16hrs at the workbench in 3 days, i was almost ready to go back to my 9 to 5 this morning... :woohoo:

using a craftsman 1.5hp bench buffer with a 8" fine wire wheel, a 6" coarse, and a 4" ultra fine.

then onto a dremel with 3/4" stainless wire wheel

then some superfine steel wool or my fine scotchbrite pad, whatever i'm in the mood for.

i'm currently sourcing a 1/2" cup stainless wire and a 1/4" straight stainless wire dremel bit to finsih the last 2% of the nooks and crannies.

i've read several places not to use wire wheels or steel wool on aluminum because some will embed and you'll get rust dots on the aluminum.

but i always liked press your luck game show. no whammy, no whammy, no whammy, STOP!

i'm thinking of taking one of the pieces and putting in a bucket of water outside my door (eeiiiieeeee!) to see if it is actually retaining steel that will rust. i'm skeptical but won't know till it gets exposed for a while.

back to work i guess...

It thought those things where spray painted! They look nice, and I was looking for the words spray paint all this time. Well of course youy do know not to put that piston outside, I know you aint no fool!

kzwolfsr wrote:

I know you aint no fool!

you just don't know me that well yet. i fubar about every fifth thing i do...

thanks, they do look even a bit nicer in person too.

the pistons i haven't touched and trust me i won't put them in a bucket, just a piece of the newly raw aluminum - probably test a caliper bracket.

i may clean up the sides of the piston with some 000 or 0000 steel wool to get those little rust spots off, will probably hit the inside of the calipers too the the spots on the pistons come off easily.

Post edited by: sheik*yerbouti, at: 2007/01/08 16:43

ok my pc is sucking, sorry for yet another double post...

Post edited by: sheik*yerbouti, at: 2007/01/08 11:11

I have experience rebuilding the front brake system of a 1981 J which by the look of the pics has a very similar caliper and MC setup to yours.

The MC has a complete replacement kit. To remove it there is a plastic tubular clip which is held by pegs into the MC body. To remove these are just pushed inwards and the whole internals can be withdrawn. There are all sorts of dire warnings about doing this yourself but as long as you are carefull its a pretty easy job. All about manufacturers liability I expect. Get the bore of the MC checked by a brake shop who shud hone it if its marked. Just insert the new kit, replace the u shaped steel washer, rubber cap and plastic clip in that order and you are done. Have a look at the exploded parts diagram on Kawasaki.com

I think other members have covered off the caliper save to say I found help necessary to reassemble. Someone needs to hold the rubber dust cover fully open while the piston is being pushed back into the caliper, just like the petals on a flower.

Despite having done a complete overhaul I still find the braking action poor, as there seems to be some movement in the sliding caliper pins which means there is a lot on ineffective movement in the lever before the brakes begin to bite.

Post edited by: Kiwiz, at: 2007/01/15 05:03

sheik*yerbouti wrote:

Any clues on how to tear down the front MC or tips on the rear MC circlip?

When I rebuilt both the front and rear MC I went to www.thriftyrider.com looked up my bike make and model and then from the parts list chose front master cylinder... no instructions but a good starting point.

your bike is there

I see lots of elbow grease on those parts!:laugh: