Front MC - Order of Assembly

[ptm]

To my primary question - Does the rubber boot G slip over piston B until the inner lip of the boot (tried to show with a line) rests in the groove in the piston B (shown with dark line)?

Has anyone encountered a spring clip such as F? Any ideas on its purpose in life?

I wish I could help, but I don't remember exactly how the boot went in. It's been a few years since I did it. I don't recall it being particularly difficult, or I probably would remember! It does go on after all the rest of the parts are in place including the circlip that holds the piston in against the pressure of the spring. At that point I think you just slide the boot in over the end of the piston with the wire around the outside of the boot at the base. I does make sense that if there's a rib on the inside of the boot that is the right size to fit in the groove on the end of the piston that it would go there, but I wouldn't force it. Once you get everything in and the circlip on, it might be obvious how the boot fits and where the other wire ring goes. Once it's all together the boot can't go anywhere since the lever is against the end of the piston, so as long as it prevents dirt from getting in I don't think it's that critical.

Good luck.

[ptm]

Well, I finally pulled out the manuals (factory, Chilton, Clymer and Haynes)and it looks like they all show the order as piston, steel washer, circlip, boot, plastic washer, then the wire ring...

[rickt]

Paul,
This diagram seems to fit with what I remember from taking the MC apart many months ago. I pulled the rubber boot out with needle-nose pliers and I can imagine that the nylon washer and the wire clip probably remained in the barrel of the MC. I just assumed that they were installed first followed by the rubber boot. You know what they say about assumptions! It makes more sense that the nylon washer and wire clip were designed to hold the boot in place.

So, I will put things together in this order and see what happens. I don't imagine that much bad can happen as long as the piston, spring, etc. are in the right order.

Just out of curiousity, where did this diagram come from? If from a factory service manual, do you know where I can find one?

Thanks again for the input.

rickt

[ptm]

The same diagram is in all of the manuals I mentioned. Clymer, Haynes, etc. often reuse pictures and diagrams from the factory manual.

I have a spare factory manual for the early GS750. I'll send you an e-mail with details.

[rickt]

Just to complete the story, I reassembled the MC last night. Once the metal washer and circlip were in place, it was clear that there really wasn't anyplace for the nylon washer (D) and the wire clip (F) to go. After the boot was worked into the barrel and over the slot in the piston, everything looked correct. I could not see any real value in pushing these two pieces (D & F) over the rubber boot. The boot appears to stay seated when the piston is compressed and released.

Hope this story might help someone else struggling with a MC rebuild. Now for the rear MC and caliper!!!

rickt

[J_C]

Back from the dead! I've been using this thread as a resource disassembling and reassembling my front MC. I seem to be having a problem pushing the piston back into the MC.... it's getting hung up at the rubber seal on the piston. Is this a procedure that needs to be done using brake fluid as a lubricant? If so, any tips on not ruining the paint on the MC? Thanks folks!

[rickt]

Yes, lots of fluid

JC,

By all means, the piston, seals, and cylinder bore should be given a liberal coating of fresh brake fluid before reassembly.

Good luck!
rickt

[ptm]

JC,

By all means, the piston, seals, and cylinder bore should be given a liberal coating of fresh brake fluid before reassembly.

Good luck!
rickt

Yeah - what he said. As far as the paint, if it's the original paint it is very brake fluid resistant - wipe it off with a damp rag when you're done. If it's not, well... be as careful as you can and keep a wet rag handy to wipe it off as soon as you get any on the paint. Be careful not to get any water inside the MC itself.

[J_C]

Thanks guys. It was in pretty poor shape so I gave it a few coats of caliper paint. I'll just try to be as careful as possible. Thanks again!