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Discussion Starter · #1 ·
Long story.



Over the winter I rebuilt the front brake (one) on the '82 GL. New seals and a braided line were used while the hard parts were cleaned several times ultrasonically. I did not touch the bike for 5 or 6 months. (spent time with the boat) When I decided to get it going last week, (I know, I know) it would not move. I opened the bleeder and closed it when I saw a small amount of fluid in the opening. The bike was free! The lever has very little free play, but the brake works well, very linear and controlable. Each time I park for a couple of days, same thing. I have to release pressure at the bleeder before I can go. I stopped for about 4 hours today and no problem. I expect the brake to be "on" when I try it again in 2 days.



WHAT'S GOIN' ON?!?
 

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+1



The return hole is REALLY small !!! Only takes a bit of dirt/dust/rubber to block it, and it stops the piston from "letting go" of the fluid.
 

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Discussion Starter · #5 ·
You may well be right. I was reluctant to accept the idea because I don't understand why it works well when riding and then pressure builds when the bike is resting with no external force being applied. What is the physics here? Have I discovered cold fusion?

When the m/c was removed, the crud inside was beyond description, yet, I did not have this problem and I did a thorough cleaning.



Oh well, winter is coming and I can take it part again.
 

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The hole is so tiny it should have been a screw-in jet type thingy. I'm hoping that switching over to the new DOT 5.1

(NO, not DOT 5 silicone) will result in faster brake release times as it's almost half the viscosity of DOT 3 or 4 fluids. The stuff is really becoming quite available at cycle shops, seems the racing rockets all specify it now as do many other newer models.



Sure costs a lot but when you consider it's not something you have to change that often I think it will be worth it.
 

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You may well be right. I was reluctant to accept the idea because I don't understand why it works well when riding and then pressure builds when the bike is resting with no external force being applied. What is the physics here? Have I discovered cold fusion?

When the m/c was removed, the crud inside was beyond description, yet, I did not have this problem and I did a thorough cleaning.



Oh well, winter is coming and I can take it part again.




Does your bike sit out in the sun? The heat could be causing expansion leading to the built up pressure. Or a neighbor kid could be playing with your bike and squeezing the handle.
 

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Probably because you cleaned the system, the crud is now mobile. Then settles in the M/C.
 

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I'll vote for that, an errant piece has found its way into that little hole.
 

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My 81 cx500c has done that the last two years. I cleand,replaced the brake line repaired the caliper, even had the honda give it a shot by replacing the parts, Kit. If the temputure does not change to much at night its not so bad. Go from 80 degrees to 60 then I have to bleed the caliper out. Funny how the masters at honda could not stop this problem. I bleed and I go on my way all day long.
 

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Discussion Starter · #11 ·
Okay fellows, I'll have to accept the jury's verdict that it is a clogged return hole. I guess that's why God made winter.



The bike is parked on the north side of the house and gets no sun. The neighbors leave it alone.



Thanks for your efforts.
 

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We could blame it on magic but really the hole is really really small. Not like a stray item couldn't find its way in there. I've been through this several times. Not sure why an overnight works better than well riding but be glad it does. I had one lock up on me while riding and it was a pain to get home. Thank god I had an 8mm wrench on me.
 

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Sticky brake problems were common with bikes of this era and was caused in the main by heat built up in the discs transferring through to the caliper heating up the fluid when at rest, increasing the internal pressure and "locking" the brake. It used to be a regular occurance on overnight tyre testing sessions etc, and in part is why they developed ceramic backings on brake pads to prevent this kind of heat transference
 

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Sticky brake problems were common with bikes of this era and was caused in the main by heat built up in the discs transferring through to the caliper heating up the fluid when at rest, increasing the internal pressure and "locking" the brake. It used to be a regular occurance on overnight tyre testing sessions etc, and in part is why they developed ceramic backings on brake pads to prevent this kind of heat transference


Now that's very interesting. I use Raybestos ceramic brake pads on my cars (I'm a rather spirited driver - have to be around here) and II've noticed that the calipers barely get warm compared to others with the same car running conventional pads.



Sure would be nice if someone made ceramic pads for our bikes.
 
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