tcoop Posted June 28, 2011 #1 Posted June 28, 2011 My rear brake system was not working so I removed the MC and replaced it with a spare that I received when I got the bike. Grabbed a can of Brake fluid of the shelf and bleed the breaks and walla I have rear front brakes now. This was all time consuming (started around 8:30 pm and finished about 12:30 am) but not real difficult. (By the way the Speed Bleeders work really well). This morning the bike would not start so I removed the TCI (it's relocated to be under the false tank) and put it into the oven on warm for 15 min. Re installed it and the bike started right up. So off to work I go. I'm lucky that my commute is only 10 miles. At the 8 to 9 mile mark the bike starts to bog down like it's under a heavy load so I shift down which help for about 10 seconds so I pull the clutch in to shift down again and the rear tire locks up...hard. I could not free it even with the engine. The cage behind me was a little close but they never hit me. I did the best I could to get the bike out of the street but I only got it out of the main traffic pattern. Luckily it was just a busy residential street. I turned the flashers on got off the bike and tried to assess the problem. (The engine is off by now). Well I figured that I did something wrong When doing the brakes last night so I checked the rear brakes (I hadn't put the panels back on just in case I had to get back into there) and sure enough the MC plunger would not move. I stood around for 10 to 15 min trying to figure out what to do. I finally went to the house that I was stopped in front of and asked to barrow their hose to cool down the brakes. So here I am practically out in the middle of the street looking like I’m washing my bike with the flashers going I'm sure people passing by thought I was insane. Well the water cooled the brakes down enough that I was able to get the bike out of the street. I was not able to get the bike to start because the flashers wore the battery down. Well if you have not guessed by now the lesson I learned is to NOT use old open brake fluid!!! I'm lucky that it didn't lock up on me while I was on the highway. So I walked the remaining mile and a half to work stopping at the auto parts store along the way and got everything I would need to bleed the brakes at lunch when I go retrieve the bike. By the way the whole time I was out in the street not one person offered to help or even asked what I was doing. Although no one on a bike came by.
MiCarl Posted June 28, 2011 #2 Posted June 28, 2011 Your problem may not be old brake fluid. If you adjust for too little free play the return hole in the master cylinder is blocked. As the brakes warm the fluid cannot return to the master cylinder and they get tighter and tighter, eventually locking up. Your pads (rear and left front) are probably glazed too. You're not the first to do this.
DragonRider Posted June 28, 2011 #3 Posted June 28, 2011 Happened to me, had to unclog that little bleeder hole in the master to make it work right, now all is good. Your problem may not be old brake fluid. If you adjust for too little free play the return hole in the master cylinder is blocked. As the brakes warm the fluid cannot return to the master cylinder and they get tighter and tighter, eventually locking up. Your pads (rear and left front) are probably glazed too. You're not the first to do this.
Squidley Posted June 28, 2011 #4 Posted June 28, 2011 Been there done that, no shirt. Had mine do the same thing, take the rear master cylinder off and completely clean it out. The return oriface is clogged and wouldn't allow for thermal expansion of the brake fluid. It had to go somewhere and it did, to the calipers and locked them up. I always take the rear MC off of any older bike I work on and completely clean it.
tcoop Posted June 28, 2011 Author #5 Posted June 28, 2011 Should both holes be clear? IIRC there wer two holes one was clear the other looked like there was some sort of diafram in it Or I could see the plunger (or it was really dirty) the bottom hole was clear.
Venturous Randy Posted June 28, 2011 #6 Posted June 28, 2011 The master cylinder probably needs cleaning, but the best thing to do to get it going is to simply bleed some brake fluid out because it was too full. RandyA
Yammer Dan Posted June 28, 2011 #7 Posted June 28, 2011 The master cylinder probably needs cleaning, but the best thing to do to get it going is to simply bleed some brake fluid out because it was too full. RandyA :sign yeah that::sign yeah that: Been there done that. I would bet you overfilled the rear master. All you have to do is open bleeder and relieve pressure. When I work on brakes I always take a 8mm wrench with me on the test run now. You do not fill the rear master full. Have to leave room for expansion.
Greekdog Posted June 28, 2011 #8 Posted June 28, 2011 I agree with squidley...MC has a plugged hole...happened to me on my front brakes. Took a wrench and relieved the pressure and rebuilt it when I got it home. Found the hole plugged, when you squeeze the handle you should get fluid squirting out....No squirt...gotta be dirt...or tiny pieces of brake seals...
muaymendez1 Posted June 28, 2011 #9 Posted June 28, 2011 Yep Been There done That. wasnt the break fluid on mine but the adjustment I was on the freeway when the rearon my 84 gold wing locked up. My leatherman andbandanna to kee the hot pipe off my arm was all I needed. Readjusted and Off I went. You could always adjust the plunger when that happenes.
tcoop Posted June 28, 2011 Author #10 Posted June 28, 2011 Well i had already bought the stuff to bleed the brakes so during lunch I did that. I found that I didn't do a good job last night. There were tons of Air bubbles coming out. I made sure the fluid level was down a little so we will see how works for the ride home. Now at least I have some tools so if it locks up again I can release the pressure.
Yammer Dan Posted June 28, 2011 #11 Posted June 28, 2011 Let us know how it comes out. If it starts to tighten up on you just crack the bleeder to let off a little. Stick some napkins in you pocket to catch the brake fluid. Best paint remover there is.
tcoop Posted June 29, 2011 Author #12 Posted June 29, 2011 Got it home ok but it did seem to tighten up a little. I'm thinking that I will clean/rebuild the MC and the calipers this week end. I don't want to take any chances.
yamadawg Posted July 10, 2011 #13 Posted July 10, 2011 I had the exact same thing happen on my '83 as a result of my adjusting the pedal free play as described above. Luckily my wife and I were able to make it into a parking lot before it locked completely up. If we were not going down hill I don't think it would have made it. Good luck, and please don't underestimate how important that seemingly innocent pedal adjustment can be on this bike...
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