Rear master cylinder failure

This really is wierd, installed second rear brake light switch in less then two years (first two were the motor company). Went to bleed the brakes got two solid pumps from the master cylinder and then nothing. Seems as if the mastercylinder just decided it had enough after 14k miles. Reservoir still had fluid in it so i did not run out. Took cylinder apart nothing real obvious. Do not know if i should put the rebuild kit in or replace completely. Anybody have any thoughts on this?
Tim

not sure, on cars it's pretty much a waste of time due to the cheap cost of a rebuilt unit. from what i've seen mc fail with age due to corrosion resulting in a pitted plugger. doubt thats the case in your situation. yours sounds more like some premature failure due to workmanship at the plant, or maybe a stuck valve, i'd definately let the steeler know about it. if i were in your situation i'd want a new unit.

It seems that the rear MC can be a real PITA to bleed sometimes, at least in my experience. Before you go and replace the whole thing, I would try some other bleeding techniques. I've used a vacuum pump and sucked it down from the caliper bleeder screw with success. You can also get a hand vacuum pump at some of the local auto parts places. I think Advance Auto simply calls them "Self Bleeders". There are others. Once I used a block of wood and some wire ties to hold the brake lever down over night. Then I bled the air out the next morning. That seemed to work well too.

Good luck.

thanks guys, my experience with the car type also the same. rebuilts are cheaper and less of a hassel. I already have tried to pull the fluid thru with a hand vacum pump thru the caliper bleed hole with no success. According to the HD manual this master cylinder can be just hooked up and it should start pumping fluid. Does not say anything about bench bleeding the cylinder first. Guess we will head to the dealer and see if he has the cylinder in stock, otherwise i will try the repair kit.

Maybe Something In The Line, I'm Sure You Use The Right Fluid, Don't Understand Why Your Switch Would Keep Going Out, Could Try To Take It All Apart And Clean It Out, Could Take The Switch Off And Pump To See If The Fluid Makes It That Far, And Back Track.

well , Had to put a rebuild kit in it , that solved the whole problem pumped right up. went for a test ride all was well with the brakes. Got back into my driveway and guess what fuel is coming out of the carb overflow like it is going out of style and the bike is about to shut off. What now , pulled the carb bowl and whole bunch of fine dirt in the bottom of the bowl , evidently there is a bigger piece logged in the needle and seatand will not shut off the fuel. Looks like the carb comes off now to get cleaned out:gah:

Look at the bright side, you are capable of doing the work yourself so you don't have to put out the bucks to have someone else clean out your carb. You might try pulling out your petcock and checking the screen/filter for small holes. Blow out all of the jets and the air passages to make sure there isn't any crude waiting to give you a return problem.

dang I got confusededed, went from brakes to carbs and didn't miss a beat......wow. ok good to go again