rear brake system excess free play.

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vapor_trail

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The rear brake pedal would use almost all of it's available stroke. The stroke length will reduce by 50% at the next quick pump. The third pump, it feels right, almost no travel. The pedal never sinks under pressure.

I've taken the master cylinder apart a number of times, worrying over the check valve at the base of the spring. all seems ok, I've been thinking of replacing the flexible hose - but I cant find anything wrong with the hose.

The original master cylinder was frozen, so I got another from whitey's classic wings, he breaks up goldwings and sells parts, i have only praise for his buisness. It was in good shape, so I used it as shipped. eventually i got a kit for it from saber cycle, along with a caliper kit, and a used piston. The only part not replaced is the o-ring between the left and right caliper castings, and the hose.

The system has been bled over and over. The last bleeding was with the entire system on the bench, caliper higher than the cylinder, rolled on its side so the bleeder was the highest point in the system.

It occured to me perhaps the bike is dimensionally wrong somehow, the fixtures for the master cylinder were not positioned correctly. So I elongated the mounting holes for the master cylinder, allowing the cylinder to be moved closer to the pedal axis. the free play pretty much vanished.

am i the only one thats encountered this? otherwise the entire bike is in excellent condition.
 
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vapor_trail

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one of the guys over at NGW kept telling me to vacuum-bleed it. So I nipped over to autozone and got this nice vac pump kit, tried it.... and bingo! it's much better. go figure.

:Egyptian:


:head bang:
 

dan filipi

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vapor_trail":2ccsntue said:
I elongated the mounting holes for the master cylinder, allowing the cylinder to be moved closer to the pedal axis. the free play pretty much vanished.

am i the only one thats encountered this?

It's the first I've ever heard of it.

When I was reading your post I immediately thought leaking MC seals but it sounds like you've rebuilt and done everything else.
Strange problem and solution.

Can you get a picture of what you did?
 
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