trouble bleeding

[FlyingAnvil]

I think a bad master cylinder, you see this on old cars all the time, you know it starts out with you having to "PUMP" the brakes and then the M/C just wears out and bleeds down inside its self usually because the bore becomes worn ect. Probably a little more critical on a bike due to the smaller volume. Some brake fluid is also hygroscopic and will attract moisture and that causes corrosion.

 

[Kimball_Walker]

Thank You.
Seems I need to break down and purchase a new one then. I was hoping to not do that.

 

[FlyingAnvil]

You may get by the first time with a good flush and clean, a lot of time it's just because the fluid does not circulate well and gunk will accumulate. Happened on the wife's truck with the clutch, the fluid and wear just gunked up and it caused to slave cylinder to only move slightly. The slave cylinder had so much stuff in there and it was cheap enough to re place the master and slave and it's worked great ever since.

 

[Kimball_Walker]

I guess now I have to teach myself how to rebuild the caliper. A little bit of a pain since this is my primary transportation at the moment.
If the caliper is not working right, would that cause the master cylinder to not draw from the reservoir? Even when a siphon is hooked to the bleeder valve?
Thank you for your response.

 

[lhaolpa]

I guess now I have to teach myself how to rebuild the caliper. A little bit of a pain since this is my primary transportation at the moment.
If the caliper is not working right, would that cause the master cylinder to not draw from the reservoir? Even when a siphon is hooked to the bleeder valve?
Thank you for your response.

The calipers aren't that hard to rebuild,just make sure that when you remove the piston,you have something in the way of the piston becoming a torpedo. Use a thin board to catch it when you blow it out with air.Clean the bore,then carefully put it back together. lha

 

[Kimball_Walker]

Thank you! I did that with the MC the first time I took it apart.

 

[bcware]

Since it's related I built this bad boy for about $3 at Wal-Mart. I have used it on motorcycles and cars; it works very well.

The bottle is a cooking oil container and the tubing is for fish tanks. You simply snip the end of the bottle to accept the tubing snugly. The other end of the tubing is easily stretched over the bleeder nipple. Since the tubing stays full of fluid the bubbles come out and only pure fluid backs up into the line; i.e. no new air is introduced. The tubing is also so long that I can do the rear brakes in my car and have the bottle next to me to note the color change from old to new fluid.

 

[xs400neophite]

Samzies...I have NO pressure in the brake line...gonna try clean MC first,then rebuild MC and calipur if neccesary. Wish I had a neighborhood Vintage Japanese Motorcycle-mart.

 

[FlyingAnvil]

I guess now I have to teach myself how to rebuild the caliper. A little bit of a pain since this is my primary transportation at the moment.
If the caliper is not working right, would that cause the master cylinder to not draw from the reservoir? Even when a siphon is hooked to the bleeder valve?
Thank you for your response.

I imagine if the piston in the caliper was lodged in there or cocked if you will, that could happen because it's bound and the fluid cant flow or compress.

 

[Kimball_Walker]

FlyingAnvil,

Thank you for the response. The piston moves with finger pressure (retracts at least) so i don't think it is lodged. I have ordered another MC, should arrive in a few days. At this point I am leaning towards an old MC that isn't able to build pressure.

 

[Kimball_Walker]

Installed new MC, brakes work perfectly. Thank you for your help every one.

 

[xs400neophite]

How much? where did you get it from? I need one too and just wondering after all is said and done, if it wouldnt be easier and cheaper to just buy a new one. I would like to rebuild mine but if its easy and not to expensive, I might as well buy a new one.The back slave cylinder cleaned up and pressurized nicely.Bled her until she was clear and no problems.I have rear brakes.The front MC piston was frozen by years of sitting and gunk/rust ect. I took it apart and gently but firmly tapped the piston from the backside and she popped out. I thought I was in business but she never pressurized. She gave me three good squirts then quit on me. Cant get it to do anything at all now. Soooo.... rebuild kit ($26.00apx.+S/H bike bandit) or new MC womnp,womp,wahhhh!!

 

[Kimball_Walker]

xs400neophite - I got it on ebay from "usa-motorcycles-inc". With shipping it cost me under $50 US. The MC was not designed for this bike specifically, so neither the brake light switch, nor the mirror fit without modification. I decided to go this route because I needed it to be reliable, this is my only transportation at the moment, so rebuilding and running the risk of brake failure was not a viable option for me.

PS, don't lose your key, I cannot find a locksmith who can make me a new one, had to modify the bike to operate keyless while still looking like it needed a key. (That was fun to do with a keyed gas cap!)

As you have already found out, rebuilding isn't hard at all. You might want to find out though if the years of neglect have caused any damage to the interior of the MC, that was my fear.

Hope I have answered your questions.

Kimball Walker

 

[xs400neophite]

Heya Kimball,
Yeah the Master Cylinder was a mess.Reddish/brown hard gunk all up in there and everything was frozen The piston was corroded but the bore polished up nice. I found a rebuild kit on 'Old Bike Barn' for $26( no shipping cost bcs I spent more then $79 there buying some other goodies) and rebuilt the MC.The snap ring was the hardest part about it but with some tips from some of the members on here(Drewpy), it was a 'snap'.Haha. Use a nail or 'toothpick' type tool. Literally looks like a dentists tool with a screwdriver handle. Found a pack of four various picks in the bargain bin at Pep-Boys for $4.99. Aleluya that worked great! I think the actual tool for that job is on 'Parts n More' for $12.00..more on other sites?
After putting all together,I was stoked to feel the hand lever pressure up .Bled them until the liquid was clear and checked for leaks.So stoked.

 

[Kimball_Walker]

Very Cool! I ended up going to three diff. stores untill I found a snapring tool that would fit. Glad to hear the rebuild worked for you!

Heya Kimball,
Yeah the Master Cylinder was a mess.Reddish/brown hard gunk all up in there and everything was frozen The piston was corroded but the bore polished up nice. I found a rebuild kit on 'Old Bike Barn' for $26( no shipping cost bcs I spent more then $79 there buying some other goodies) and rebuilt the MC.The snap ring was the hardest part about it but with some tips from some of the members on here(Drewpy), it was a 'snap'.Haha. Use a nail or 'toothpick' type tool. Literally looks like a dentists tool with a screwdriver handle. Found a pack of four various picks in the bargain bin at Pep-Boys for $4.99. Aleluya that worked great! I think the actual tool for that job is on 'Parts n More' for $12.00..more on other sites?
After putting all together,I was stoked to feel the hand lever pressure up .Bled them until the liquid was clear and checked for leaks.So stoked.

 

[drewpy]

glad its worked out for ya!

 

[arfstrom]

I wanted to get my 3 cents in also, I also went though the MC/Piston trials, and I replaced alot of it. I started with a kit for the MC. (did solve the problem.)((But it was still needed)) Replaced rubber line with steel flexible line, with 2 banjo bolts that will fit onto the steel line. then finely pulled off the front brake, Used a air compressor to pop the piston out, (I used the shipping air bags to stop the piston from flying out of control) (Talk about an POP) So the thing I wanted to share was I used an old "camelbak" hose to attach to the bleed nipple. I was able to "draw a vacum" which was able to pull the DOT3 fluid down to the piston. Okay I sucked on the straw (camelbak hose) and I realized that once the all the air was pulled out, I could see it, and I didn't have to worry about the air getting back in. I thought that was kinda slick. Okay this wasnt worth 3 cents, special since BCWare said the same thing.
Tobie