[Phils a winger at last]

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front brakes on my wing have been known to stick on after use, result smell of burning pads and not a lot of progress. Usually freed by rocking back and forward

I'm also assuming that this could be the cause of a lack of power when accelerating

Have assumed that it's the return bleed hole in the master cylinder that is the culprit as when I took out the pads the pistons seem free enough moving backward and forward. So have bit the bullet and pulled the master cylinder, when I drained the fluid from the reservoir, empty into a dish after removing cap, I found seddiment in the fluid and in the corners of the reservoir, also in what appears to be the feed drain.

Have managed to pull free the plastic reservoir and looked at the 'feed drain' and can see one complete hole and one hole that appears part drilled, is this the return feed and is it a very fine hole, i.e. thickness of a wire strand, that may be blocked and can be unblocked. Have now bought a set of good circlip pliers and am about to pull the seal/piston and then clean everything out.

Thoughts please gents on the following

Am I right in what I'm thinking that the return hole blockage could cause this

If so what is the best method of unblocking and would a bigger hole be a problem

Do you need to glue the plastic reservoir to the master cylinder, if so what glue

If the piston and spring look OK would you just replace the seals, if they look OK just put in fresh fluid and bleed

(was going to change the pistons and seals but they look ok, minor corrosion marks and no leaks - better condition that my 06 suzuki 500 pistons)

I look forward to hearing from you, while I may not agree with all the responses they are valued and will be taken on board

 

[Silicon Sam]

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You'll have to agree with this one, cause it's the fact. The reservoir cup is held onto the master cylinder with the 2 screws that hold the lid on as well. There is an o-ring on the bottom of the plastic cup that keeps the fluid where it belongs.

Yep, unplug the hole, don't make it bigger. A strand from a stiff wire brush would work.

 

[litfuse]

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Don't forget that wheel cylinders are kept in place by a plastic sleeved stud with a bolt in the center that has got to be positioned in the correct alignment because of a shoulder.Could also be your problem like mine was. Fred

 

[sandcastcb750]

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I agree, the bleed hole could be plugged and keep brakes applied.

However, make sure the caliper pistons aren't stuck which would produce the same effect.

 

[Phils a winger at last]

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three out of four pistons move easily, the other one moves, litfuse are you referring to the two pistons in the caliper, cant say I've seen a bolt anywhere except for what holds the caliper pins in position.

 

[sandcastcb750]

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Maybe you have a stuck brake piston. The two brakes are stopping the same wheel and you can't tell which one while riding.This is the most common stuck brake problem.

Rebuilding the master cylinder after years of use and sitting can't hurt.

If sticking, they lock up more when they heat up. Touching the rotor for temperature can tell you alot too.If you are correct that one piston is sticking, one rotor will be cool, the other hot.

 

[Phils a winger at last]

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I'm assuming one (small) piston is sticking slightly as when you pump the lever it is slow to come out until the larger one has come all the way. Normally I work them back and forth using a G clamp to push them back in, may be a full strip is in order and a caliper clean up with new seals

 

[oldyardman]

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my old 83 1100 would stick till I clean up the pin the caliber travels on,got to keep them clean and very little bit of lube or they will hang up

 

[sandcastcb750]

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I went down a dusty dirt road last summer and the rear brake started to stick. Dirt can cause a problem. As they heat up, they stick more.