Broken-Hearted over '78 kz1000 rear brake!

I suppose it's too near the Holidays to be broken hearted, but there it is, sh**t.
Here's photos after I turned my '78 kz1000 rear brake master cylinder upside down and filled it with carb cleaner, then Penetrating Oil and let it set 2 full days.

I then today used a bigole tap and once I got the tap in the end of the master cyclinder's piston (which IS real stuck btw) I tried using the T-handle of the tap to pull the piston or even get it moving at all -- NO-DAM-LUCK-A-TALL.

Here's the parts diagram, '78 kz1000 rear brake master cylinder -- the master cylinder piston is part #9 and it has a hollow end, and I screwed the tap into that hollow end of the piston:


HERE'S THE SEEMINGLY 'INTELLIGENT' EFFORT UNDERWAY AN GETTIN NO-WHERES:









You can see from the parts diagram that the fluid reservoir doesn't come apart so I don't see a way to PUSH the master cylinder piston out from the top -- only seems as though it can be PULLED out and I'm using a tap and it's not working.

ANYONE HAVE ANY IDEAS? This thing's making me work too hard.

look in bottem of resevoir for screws holding it on

BFH?

Good idea, but I tried that -- here's a picture of the bottom of the reservoir:




It seems like the bottom plate with the 6 holes in it could come off, you'll notice there are 4 sets of little tabs (the tabs are seen as the sets of parallel line cut-outs at the outer circumference of the 6-hole plate).

But I didn't remove it, seemed like I'd have to break the tabs to get it out, and so I then looked at the parts diagram which shows the reservoir does not unbolt from the piston shaft just below it.

Still stuck on this.

Did you remove the ring (part #11) and piston stopper (part #10)?

650ed wrote:

Did you remove the ring (part #11) and piston stopper (part #10)?

Very most definitely, I had to do that for 2 reasons:

1) to clean the exposed part of the bore not covered by the piston, so that the MC piston would more easily slide its way out to the end

2) and if I succeeded in getting the piston to move from its 'stuck in the fully-depressed condition' down the shaft and away from the reservoir, I needed parts #11 and #10 out of the way as I intended to inspect the condition of the piston and its rubbers etc.

Did that 3 days ago before I set about cleaning the bore in prep to pull the piston out. Good suggestion though.

I RECKON WE GOT REEEEEEAL CLOSE ON THIS ONE, Dad always said 'If there aint no one to 'teach you a lesson you better teach that lesson to yourself' and to me that spells S-L-E-D-G-E H-A-M-M-E-R on my right big toe there:



Now if you look closely you'll see that toe's still recovering from the most recent incident, and I thought "Before I cause myself to pass out here again, *maybe* I had better give that piston ONE MORE TWIST-N-TURN, yeah that's better than another long toe smash recovery

ANNNNNND IT WORKED:





I feel a lot better about that toe.

Funny thing is -- I don't find the spring part #7.
Might still be stuck inside, oh fine.

Would have had it out long ago with the grease fitting fix but then your toe would have felt left out of the process I guess!

Kawboy74 wrote:

Would have had it out long ago with the grease fitting fix but then your toe would have felt left out of the process I guess!

I want one, where can I get one? As I looked into the discussion of that fitting there it seemed a bit of machine shop know-how is required which I lack, do they sell those? The other thing is it sounded like the fitting was for the *caliper* piston, not the master cylinder piston, but if it works on either MAN OH MAN WHERE CAN I GET ONE. Post-toe-matic stress syndrome is to be avoided during the holidays.

The fitting screws into the banjo bolt hole so it is likely the same size as a caliper banjo bolt. I had a friend machine it out of a bolt that was turned down and tapped to suit and then the flat on top was drilled and tapped to suit the grease fitting. Leave the fluid cup on the cylinder as it can be removed later by lifting out the bottom plate carefully and undoing the screws. There is an o-ring between the cup and the aluminum body that should be checked and the area cleaned well anyway judging by the shape of that piston. Check the bore carefully after you have fully cleaned unit being careful not to scratch the surface and off you go with a kit. Good luck! David

Check the bore carefully after you have fully cleaned unit being careful not to scratch the surface and off you go with a kit. Good luck! David

Kawboy, where might I find a '78 rear master cylinder rebuild kit for a kz1000, A2 standard model? I hope they are more plentiful than my front brake, only thing I found was that Z1 Enterprises was willing to sell me *only the piston* for $45, not even a full rebuild kit, so I found a used kz650 for sale with identical front brake and bought that for $40, it was fully functioning and I just removed my old parts and put on the new front master cylinder, presto fully working front brake (got lucky there) -- there just aren't any rebuild kits for the 1978 A2 kz1000.

I'm hoping I'll have better luck finding a rebuild kit for this back brake master cylinder but just checked ebay and NOTHING.

Any ideas/source you know of?

Well I found a rebuild kit for rear brake master cylinder for the 1978 kz1000 at www.z1enterprises.com -- for $72.61.

And at www.kz900.com -- EVEN WORSE: $87.99.

YIKES. :ohmy: :X

I'm gonna stay with my current parts, gonna clean em up and go with em. Nothing is cracked or broken or worn out. Not new but physically, all the rubber bits are FINE and thats the most important thing.

Only thing I need to do is polish up the bore a tad, there's a ring down deep where the piston was stuck up, not a big ring, but need to buff it out down in there -- WHAT DO YOU RECOMMEND? Need something to get deep into the bore where the ring is...