rear master cylinder is pissin me off

I still found crystallized old junk in the bottom of the master cylinder -- I took a small spring puller tool (looks like a screwdriver but has at its end an L-shaped bend with pointed tip) and removed the crystallized junk as much as I could, then sloshed around some brake fluid in the m/c cupand poured it out then used the air compressor. Nooks and crannies at the bottom of the cup sheesh.

I got the m/c to pump out fluid finally.

Next I checked the brake hose -- I blew on the end of the hose and no air pressure at the other end. I hoped the pressure from the m/c would clear it but no dice -- I hooked up the m/c and simulated opening/closing the bleed valve that's on the caliper by putting my finger and thumb over that end of the hose -- no pressure, no brake fluid, no suction felt either.

So I'm thinking about running a 14 or 12 gauge copper wire down through the hose -- I suspect that if the m/c had as much crystallized brake fluid as I found, that stuff is crystallized in the hose too.

Is there an alternate way to clear a brake hose besides using a length of solid (not stranded) copper wire as a rooter?

I would suspect that if those are original hoses,not only are they stopped up with crystallized brake fluid,they are also ay least partially dry rotted.If u can I would just get a new set of steel braided teflon coated hoses from somebody like Spengler amd be done with it.If u cant,I have a set of hoses around here somewhere that came off my bike ur welcome to.bj

newOld_kz1000 wrote:

...crystallized old junk in the bottom of the master cylinder...checked the brake hose -- I blew on the end of the hose and no air pressure at the other end....

With this much sediment in the m/c and hose, might also expect to find the caliper chamber and piston in pretty bad shape.

Sometimes water can settle inside the caliper chamber and wreak havoc.

Good Fortune!

Patton wrote:

newOld_kz1000 wrote:

...crystallized old junk in the bottom of the master cylinder...checked the brake hose -- I blew on the end of the hose and no air pressure at the other end....

With this much sediment in the m/c and hose, might also expect to find the caliper chamber and piston in pretty bad shape.

Sometimes water can settle inside the caliper chamber and wreak havoc.

Good Fortune!

Excellent point, I reasoned in that direction too, so tomorrow I will pull the rear caliper and clean it. There was a lot of junk in the m/c.

I got the brake hose clean through using my solid copper wire-as-rooter idea I had earlier today. The first strand of 12 gauge solid copper wire (sourced from a roll of 12/2 I had laying around from doing a wiring job and stripped bare of its insulation) -- the first strand did not make it all the way through the brake hose, but *almost*.
Here's a picture of the brake hose and the copper:




Note that one of copper wires is broken in 2 pieces -- it almost got caught inside -- what happened is, when I had got the copper wire almost all the way through the brake hose to the other end, it got stuck (on the blockage in the brake hose, I'm guessing).

I used needlenose pliers to wiggle the copper and move it up and down to try to poke through the blockage but the wire snapped at the end of the hose where I was feeding it in. But I got the wire out with needlenose.

So for the 2nd roto-rooter via copper try, I started at the OTHER end of the brake hose and sure enough -- the copper stopped about 1 1/4 inches into that end of the hose. Must be the blockage.

So I rotated it, plunged it up and down -- and then -- a shytload of dark dirty brake fluid come out the other end and I knew I had probably broken through the blockage.

I went ahead and rooted the copper wire through the brake hose, then removed it and you'll see in the photo, this time I didn't break it.

So now I can move air into and out of one end of the hose and feel noteworthy pressure or vacuum at the other end when I put thumb+finger over that other end.

So the hose is good to go.

Next up: yank and clean the caliper. Patton is spot on, there is sure to be lots of crystallized junk inside. That master cylinder and the hose were nothing but crystallized fluid.

This bike sat 12 years, I have never seen or heard of brake fluid so old that it puts a block in the hose.

I'm surprised that I got the piston and other parts out successfully and that they still work. I tried it on the front master cylinder on this same bike and ruined it.

I'm as cheap and/or poor as anybody, but please, buy a new hose. Brakes aren't the place to cheap out.

Brake Lines
www.spieglerusa.com/cfm/brakelines.cfm
www.helusa.com
www.russellperformance.com/metric_two-line.shtml
www.goodridge.co.uk/motorcycle-brake-lines/kawasaki.htm

If you get the brake lines with no over coated protection(like a heatshrink sleeve) the lines will act like a slow speed file,wearing through paint,electrical wires, and other brake lines.

I appreciate the concern but I'm doing what I call a 'vagabond restoration' here.

EDIT: this bike was not run for 12 years, was sitting in the original owner's back yard for all that time under a tarp. My original goal when I got it was to get it 100% functional then efficiently spend $$ only where needed. It took a lot of time and effort to get it there but it's almost ready for investing in needed new parts.
END EDIT:

Instead of starting with a non-running machine and commencing buying all sorts of stuff, I like to establish a confidence-building baseline of operation.

I work with only what I have to start with. I get everything back to normal operation without regard for putting the bike on the road immediately.

So far I've got only a small investment of oil/filter, used front master cylinder, plugs, carb jets and a couple valve shims.

My 'vagabond resto' has the goal of establishing completely normal (if not 'daily-rider-ready') functioning of all components: electrical, suspension, brakes, engine, fuel supply/delivery, and rider comfort (seat/bars/levers/gauges).

Once I've been through the bike and used every existing component that is still operable (if not road-ready), I end up with a running and completely functional bike in all dimensions.

From that solid foundation of complete awareness of all the bike's issues (paint, maybe some exposed wiring, torn seat, old brake lines, tires with cracked sidewalls, gaskets leaking) I have a really thorough understanding of where I need to spend and where the existing stuff is fine.

So several things on this bike will be swapped out prior to making it a daily rider. It's currently on 'Non-Op' with the DMV and that won't change until the bike has roadworthy tires, brake lines, some heatshrink to cover some exposed wires, and so on.

I like to completely know the bike's issues and get it as close as possible to road-worthy before I spend.
It's really confidence-inspiring before you start spending $$ that you *know* you have a completely functional, running bike that only needs a few updated parts.

Okay, I cannot get the pistons to come free from the rear caliper.

Recall this is a 1978 Kz1000 A2, and I've got a fully-functioning rear master cylinder; the brake hose is clear.

So I hooked up my hand-held manually-operated disc brake 'quick-bleed' pump (Harbor Freight, $24.99).

And sure enough, the reservoir included with the quick-bleed pump is filling up with brake fluid. But the brake pistons were not moving (I had the bike up on the centerstand and despite brake fluid successfully making its way from the m/c to the caliper bleed nipple -- the back wheel still spins freely.)

When it got to the point where my quick-bleeder vacuum pump was doing nothing more than sucking brake fluid out of the m/c and no more air was in the line -- I took the following steps:

- removed the back wheel
- removed the caliper
- separated the caliper into its 2 halves
- used high-pressure air to blow out the fluid channels in both halves of the caliper

Using high-pressure 110psi air will NOT pop out the pucks.

So I'm gonna have to grab the pucks with vise grips on 2 sides and pull 'em. They're sticking out enough to grab on to the edges at 180 degrees with 2 vise grips and PULL.

I have done this before to successfully extract stuck brake pucks -- the very edge of the outside of the puck gets scuffed from the vise grip, and then I filed them down. The outermost edge where I grab never fully descends into the caliper anyway -- it is sticking out a bit most of the time.

However, besides compressed air or a vise-grip approach -- what's a better way to get the pucks freed up?

This bike sat for 12 years and the pucks were exposed to moisture on the outside from the elements, and from the inside by crystallizing brake fluid.

Anyone have any ideas on getting stuck pucks out of the caliper (see the info in y explanation just above this) ?

pb blaster the entire halves..let them sit for a day.....wont eat rubber and should free everything up......you got nothing to lose...you are going to have to do a full rebuild on them anyway......

keith1 wrote:

pb blaster the entire halves..let them sit for a day.....wont eat rubber and should free everything up......you got nothing to lose...you are going to have to do a full rebuild on them anyway......

Will do, hadn't thought of it, was worried that getting anything other than brake fluid inside the channels where the brake fluid flows would cause a problem?

Would it make sense to soak the 2 halves, with all the brake fluid ports open, in 'Marvel Mystery Oil' for a day or so? I have a gallon jug of MMoil unopened at the ready.....total immersion is what I'm thinking.

Will the MMoil or the PB Blaster cause issues if it gets inside the brake fluid channels?

newOld_kz1000 wrote:

keith1 wrote:

pb blaster the entire halves..let them sit for a day.....wont eat rubber and should free everything up......you got nothing to lose...you are going to have to do a full rebuild on them anyway......

Will do, hadn't thought of it, was worried that getting anything other than brake fluid inside the channels where the brake fluid flows would cause a problem?

Would it make sense to soak the 2 halves, with all the brake fluid ports open, in 'Marvel Mystery Oil' for a day or so? I have a gallon jug of MMoil unopened at the ready.....total immersion is what I'm thinking.

Will the MMoil or the PB Blaster cause issues if it gets inside the brake fluid channels?

i wouldnt think so.....your main goal here is to get everything apart intact, analyze what needs replaced/repaired,clean everything out, order what you need , and put it back together.....it doesnt matter what you use....you are cleaning everything anyway.....