Brake help please

[grumpy]

1995 GL1500 SE w/Lehman straight axle, drum brake conversion, 98,XXX miles. While on a trip approximately 2,500 miles after installing speed bleeders & replacing the brake & clutch fluid, lost all braking in the rear circuit. Parked after a day of riding with normal braking, went out next morning to go some more & no rear brakes. No sign of leaks where parked. Reservoir was empty. Filled reservoir, bled brakes & all was normal. When I got home (about 2,500 miles later) I removed the rear drums & inspected all braking components, including the front left brake. NO evidence of ANY leakage anywhere. NONE. Inside of drums was very dusty, shoes are about 50% worn, but completely DRY. Any suggestions as to where the brake fluid went? I am stumped. TIA, Stan

 

[CrystalPistol]

During this trip home after the refill and bleed did you ever check it again?

I have a '97 Lehman, likely same GTL kit with same brakes. There's the rear brake reservoir, a supply hose down to the rear MC, the two brake lines leaving the rear MC (one to left front and one to a rear swing arm fitting) ... then there's a line from the fitting to a tee at axle and two steel lines to wheel cylinders.

Somewhere there's a leak .... even if only under pressure.

 

[Gorilla]

was the reservoir empty when you got home? You don't say. If it was then it has to have gone somewhere. If all is dry in the rear then it might be the reservoir itself and it is being wicked away in the air-stream. Only a thought on my part.

 

[grumpy]

Reservoir was still full when I got home. I checked it daily on the return trip.

 

[CrystalPistol]

It was empty while you were out on your trip after the brake work .... but now it's still full after several days coming home .... but again no brakes and no leaks?

Did you just get on it and find no brakes sudden like .... or did you notice a diminished braking over the course of the trip?

My best guess now is either an internal leak in the rear master cylinder .... or it needs a really good bleeding which is the most likely between the two, certainly the easiest.

 

[Gorilla]

Grumpy I may have missed something. After you found the reservoir dry and re-filled and bleed brakes, came home did you still have brakes? If so then you are asking where the fluid went at the start of the trip after the fluid change correct?

 

[CrystalPistol]

Grumpy I may have missed something. After you found the reservoir dry and re-filled and bleed brakes, came home did you still have brakes? If so then you are asking where the fluid went at the start of the trip after the fluid change correct?

Maybe I missed something .... after re-reading I think you are likely right.

Like ..... he did brake work, filled, went on trip, got there, no brakes, fluid gone, refill, bleed, and come home ..... and just wondering where the fluid went the first time?

If he just got a poor bleed and on the trip, air migrated up and fluid down to lines and wheel cylinders ... he never had good braking.

 

[grumpy]

crystal & gorilla
Installed speed bleeders & did a fluid flush/refill before the start of the trip. Approximately 2500 miles into the trip the reservoir was empty, no brakes. Normal braking at all times prior to this, including when I parked the night before having NO brakes & empty reservoir the next morning. Refilled reservoir & bled brakes. Normal braking for the rest of the trip, approximately 2500 miles to home. I checked the level daily. Braking was normal at all times. Reservoir was full when I got home. I have inspected the entire system except the line to the front left brake where it is buried under the tupperware & find NO evidence of leakage. I assume there is at least one connection in that line that could leak. If the system had lost fluid on the second half of the trip, I would be willing to tear the whole machine apart to find said connection, since I can't find a leak anywhere else. Since it did not lose fluid, I am stumped. That brake fluid went SOMEWHERE. I may have to go with this: FuzzyWuzHe

Man ... people will steel anything now a days ... but brake fluid???? :Shrug:​

 

[Catfish]

Man ... people will steel anything now a days ... but brake fluid????

Sorry to say, but brake fluid isn't stolen to be reused. One option is left...

Fluid doesn't escape from a closed vacuumed system without an opening and there are devious people in the world that enjoy placing others in danger. Not exactly reassuring, I know, but should be taken seriously, possibly reported and documented with law enforcement. :Shrug:

 

[Gorilla]

Any chance at all that one of the speed bleeders was loose and got tightened when you re-bleed the system? Or maybe one of the bleeders got stuck open a little then closed up when you re-bleed. That's about the only thing I can think of. If so, it would have to be very slight to take 2500 miles to lose enough fluid to empty the reservoir. I suggest keep checking it for awhile. When you become comfortable that it is staying full then you can say it was one of those things.

 

[CrystalPistol]

Any chance at all that one of the speed bleeders was loose and got tightened when you re-bleed the system? ... etc ...

Yeah .... and the trail wouldn't be so noticeable (or maybe just wind took the whisps away) as it'd be expected since they were bled before ....