Topic: rear master cylinder shot

[red_haint]

well, i'm gonna shoot the stinkin thing, spent all night cleaning the calipers and front MC, but when I went to disassemble the rear MC..well it was bad.  There was no fluid in the system, and what was left had dried out so I was slowly scraping out the residue and powdered brake fluid, but when I went to remove the guts it was a no go.  I was able to pound it in, but the spring is either too weak/broken/whatever or the whole setup is siezed too bad. 

My question is, is there another MC that would work (haven't found one on the bay), or, since i personally use the rear back very rarely, can I get away with just plain not having one?

[kuyarico]

A rear MC rebuild kit would cost you between 30 - 40 bucks. Check some of the vendors in the FAQs. I personally wouldn't ride without a rear brake. I do use both front and back regularly. I think it's an important part of proper handling. Anyhoo, I would replace or rebuild the rear MC for the simple fact that it could someday save you if your front brake fails for some reason.

[red_haint]

ahh but i cannot rebuild the MC as I cannot get it open, I hooked up an air compressor and set it for 50 psi and the internals didn't mive a millimieter, this I know because I used a micrometer to check! Would any ol MC work?

[kuyarico]

I don't see why another MC would not work. People replace the front MC's all the time to provide proper clearance for clubman and clip-on bars. I personally have no experience with this.

[crazypj]

Shouldn't be too difficult to find something with same bore size and mounting hole pattern. May have to get a little 'creative' with hose routing but thats not a big deal.
I have some Suzuki rear M/C, bolt spacing 45mm, tapped for 6mm bolt, half inch bore. Yamaha XS650 looks 47 or 48mm bolt spacing with 8mm bolts (cant check accurately as its still on bike)
PJ

[red_haint]

Wow, seems simply complicated! I think i'll keep looking for another MC.

[mick750F]

   They do show up on ebay pretty regularly. Usually when someone has decided to completely part out a bike. Have you tried soaking your mc to get it freed up or is it too far gone?

Mike

[red_haint]

I think it's too far gone. I have been soaking it for awhile to no avail as all the gunk is through the little holes and I can only get so far with my tools, the rod is most likely siezed, and unlinke the front I have no way to push it from the other end.