Rear Master Cylinder Question

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Ken Gluckman
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Rear Master Cylinder Question

Post by Ken Gluckman »

My rear brakes were binding when I took the bike out from a long period of non-use. There was a lot of gunk around the master cylinder and I hadn't changed the fluid in a long time (I know -- shame on me...). so I decided to rebuild the rear master cylinder and the caliper.

After disassembling the rear master cylinder, I noted that there are two holes in the port that leads to the reservoir, one about an eighth of an inch in diameter and one about a sixteenth. The eight inch one is clear and runs to the main cylinder. The smaller one, however, doesn't seem to be open. I tried probing it with a tiny drill bit, but it is definitely not open to the main cylinder.

Shouldn't both holes go to the main passage? I am thinking the the smaller one is the bleed and, if it is blocked, that would answer why the brakes were getting stuck. But I am hesitant to really force my way through it until I know if it should be open.

So my question is -- should both holes in the port leading to the reservoir be open to the main cylinder?

Thanks for the help.

Ken

Rick Pope
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Re: Rear Master Cylinder Question

Post by Rick Pope »

Ken,

I believe you are correct in your thinking, but I'm sure the real expeerts will chime in here in the morning.
Rick Pope
Either garage is too small or we have too many bikes. Or Momma's car needs to go outside.

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Goss
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Re: Rear Master Cylinder Question

Post by Goss »

Hello Ken,

The answer is yes, if you look down the bore of the master cylinder you may see the holes. I use a very small piece if wire from my wire brush to push through this hole then spray brake cleaner and compressed air through the hole.

Good luck.

Regards

Goss
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Ken Gluckman
New Member & Happy To Be Here
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Joined: Wed Mar 26, 2003 9:15 am

Re: Rear Master Cylinder Question

Post by Ken Gluckman »

Thanks for the quick responses. I used a piece of wire brush as mentioned and it cleared out.

Ken

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