Master Cylinder Problems...

[coolksprt]

Soooo, I've put the MC back together again, and the same problem proceeds. The piston will come out, but eventually. It pushes the lever out so slowly that its obviously not correct still. I just don't get what would happen for it to stop working properly like it used to when I first got it. All the parts are in fact clean, I can assure you that. So the only last idea I have that it's a weak spring? Im all open for ideas.

Thanks

Kev

[coolksprt]

Be sure to not use WD40 or any other petroleum product when cleaning or assembling brake parts.

huh...well..that could be problematic...
I haven't hooked the MC up to any hoses or anything yet, so should I be fine if I can clean it out with brake fluid?

Kev

[almarconi]

A rebuild kit is about $25, just rebuild it.

[coolksprt]

Almarconi, I think I may end up having to do that. But I'm the type of person who likes to figure out whats wrong, try to fix it, and if I can't, try to determine what happened so it wont again, or to be able to fix the problem if it rises again. I've been trying to do this with the GS since I recieved it half a year ago, and wouldn't be able to do it without outside help from here.
Some people may call me "stubborn", but I don't like to give it up just like that. I do appreciate your help so far of course.

Any other ideas, I'm all open.

Fixer upper,

Kev

[cdnoel]

Rebuild kit is the only way to go.

A "rebuild kit" and making sure those two holes are cleaned is the only way to go. My step dad refused to clean his XS11 master cylinder on the grounds that a $1000.00 bike should be just that and not have any more money spent on it. That logic didn't stop the thing from fliping over endo on him when the return valve got stuck while going down a hill.

[seuadr]

i had the same problem with mine, the rubber looks pliable enough, but it's not up to snuff. i'd rebuild it as well.

[coolksprt]

I was looking on Z1, but they only have rear MC rebuild kits. Suggestions for worthy enough sites to help out a riding deprived kid???

Kev

[seuadr]

well, www.partshark.com has a GSR member here, and they usually are pretty cheap as far as prices go. might check them out. you can contact chris@flatout (that's the GSR member, not an email address) by PM and he's great to work with.

[Matchless]

Soooo, I've put the MC back together again, and the same problem proceeds. The piston will come out, but eventually. It pushes the lever out so slowly that its obviously not correct still. I just don't get what would happen for it to stop working properly like it used to when I first got it. All the parts are in fact clean, I can assure you that. So the only last idea I have that it's a weak spring? Im all open for ideas.

Thanks

Kev

Just a thought,
If you are looking at a slow return of the piston before you have filled and bled it, you will normally be pushing it in to its furthest/deepest position where it normally does not go when under pressure and should still return properly, but may be binding deeper in.
I have a M/C that has the actual piston front edge lightly scraping on the inner bore. Another piston did not do it, seems like the piston was not OEM and slightly bent??? I could see the shiny part on the front lip of the piston on one side only and also had it sticking when not bled.
A kit has new rubbers, spring and piston.

[coolksprt]

Well....

I think I have most likley found the problem. While using the "brake fluid" to flush out and assemble the MC, the fluid appeared to be not the normal color. I've been using valucraft (never heard of before) so I thought "Hmm must be some brand thing." But to my lucky surprise, my dad had MIXED transmission fluid with the DOT 3 braking fluid. He said he thought it was the same thing, just different colors cause he read somewhere it did the same thing...(he's a chef, not a mechanic thank god) So with some research and common sense, I'm pretty sure that red s#*t has made the rubber seals just a smidge bigger. And thats why the MC doesn't retract properly since there's to much force on the bore now.

Now I know that the rubber parts are pretty much shot, unless there's a way to clean them with brake cleaner or something maybe hopefully?

thanks again guys.

Out of luck,

Kev

[duaneage]

Clean everything with denatured alcohol thoroughly and use compressed air to dry. Get a can of dust off compressed air, it has no water in the stream unlike most air compressors. ATF is a serious contaminant. You want to minimize the introduction of water into the system since brake fluid rapidly absorbs it and causes rust. Denatured alcohol is recommended in the factory Suzuki service manual for cleaning brake components. Rubbing alcohol, the common name for isopropyl alcohol has water added and is not appropriate.

If you want to cover all bases open the calipers up and clean them out too.

Sounds like a lot of work but stopping is more important than moving, especially when there is a truck in front of you at a red light.

[Nessism]

I suggest you replace the parts with NEW OE Suzuki parts. My experience with aftermarket rebuild kits (K&L brand) is similar to Matchless's, the piston bound up in the bore. I still have that POS kit sitting in the spares box - paid too much for it to throw away even though its junk.

[duaneage]

Yeah, I popped a few extra dollars at the dealer for a real Suzuki master cylinder kit in a SGP bag. It was identical to what came out and worked like a charm. At 43 dollars it was only 10 dollars more than aftermarket. I don't mind spending another 10 dollars on better parts.

Some of the aftermarket stuff doesn't include the bowl ring gaskets, or other seals.