Clutch master rebuild kit

[alvald83]

I have a replacement clutch master cylinder in hand and have a rebuild kit on order from the dealer. I just have a few questions.

1. How do i separate the electrical wire (thats a strange lokking connector)?

2. wheni look into the bowl, i see 2 holes on the bottom. One seems to be plugged (not sure if there is a valve there or not). Is that normal?

3. How difficult is it to rebuild it? Should i leave it to the shop? (This years bike repair budget is long gone)

4 . What is in the $39 dealer rebuild kit?

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alvald

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[mbrood]

1. The clutch switch has a thin plastic "arm" on the bottom with a little button on the end. This needs to ge gently pushed in through the hole in the metal housing and the switch will back out.

 

2. The large hole is the fluid fill hole while the tiny one is the relief hole... the master cylinder piston and seals are directly beneath these. once you have the lever off along with the plunger and boot, you will see the circlip inside there... get that out and the piston and spring will come out and NOW you can inspect those holes for clogging.

 

3. Rebuild is straight and troublefree... once you have siphoned out the fluid from the reservoir, it goes very rapidly. No shop required.

 

4. seals, springs and plunger, I believe.

[dingy]

The connector has a tab that is engaged in a hole on bottom side of where it slides into master housing.

 

The 2 holes are the main flow & and a smaller relief hole. It is an extremely small hole.

 

At work we have piano wire in all the small sizes for making springs. I think the largest wire that would go into a master that I had was #14.

 

The tough part of rebuilding is getting the cir-clip out of the housing that holds it together. Not many c-clip pliers will reach in that deep. If you have a new clip, you can engage the old clip with a pointed tool like an awl and bend it inward to help get it out. New one goes in easier, once it is started in bore, push it down till it engages slot.

 

Main thing to look for is that small hole is open & there is absolutely no surface imperfections where the seals ride deep in bore.

 

Gary

[alvald83]

Thanks! you guys are great!

Everytime i go to dealer for service, they tell just get a new bike.

[bongobobny]

While you have the master cylinder apart, you want to inspect the bore for pits, ugly scratches, etc, and hone it out if possible. You need a very small hone to do the job. Just plain replacing the old rubber helps, but if you really want to do it right you should hone it as well.

 

Yes, hopefully for $39 you should get new seals, new piston and new c clip. I found sears craftsman c clip pliers seem to work the best...

[alvald83]

Ok, Now for the bleeding sequence. Is there anthing i have to do besides just just opening the bleeder screw down under the rubber cover? I hear its easier than bleeding the brakes.

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alvald

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[Condor]

On the circlp. If you press the plunger rod down into the cylinder and stick a small screw driver thru the large hole in the reserve to keep it depressed it makes getting to the circlip much easier. I went down to Harbor Freight and picked up one of those small plier sets and ground a notch in the tip of the needle nose. Makes getting the clip out a no-brainer....

[bongobobny]

That's pretty much it! Use a vacuum pump and it will be easy as pie. You may also want to install a speed bleeder. A speed bleeder is just like a regular bleeder but it has a one way valve in it which allows fluid to flow one way onlt, out. No air gets sucked back inside when you release the clutch handle. You micht want to prime the master cylinder before you reattach it back to the hose if you remove it to rebuild. Just put some fluid in the resovoir and pump the handle a few times until fluid comes out the end...

Ok, Now for the bleeding sequence. Is there anthing i have to do besides just just opening the bleeder screw down under the rubber cover? I hear its easier than bleeding the brakes.

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alvald

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[foxman]

[ATTACH]65649[/ATTACH]

 

Exactly where does the seal go?

[mbrood]

Going into the hole first... spring... then rubber cup over spring, fit the seal over the long smooth shank of the piston (smooth face of seal to the outside), then piston goes in with seal to the outside, then washer and circlip. Small spring then rubber boot. The lever linkage shaft goes into the small spring to move the piston.