View Full Version : Riddle me this Batman.... Where did the brake fluid go?

06-11-2012, 12:23 AM
Dug out my wife's motorcycle today, figured out my long standing carb issue (primary and secondary jets were swapped) and found one other odd issue. The brakes were just about empty.

No puddle, no residue... nothing. :120:

Im confused as all hell. I rebuilt the master cylinder last spring, and it got 1 mile on it in the last 2 years. It has to be a leak, but the front tire and rim show no fluid, nor any rust trail (brake fluid loves to suck in water).

F'n squirrles??? :kyle:

06-11-2012, 08:07 AM
Did ya fill it back up when you were done?

Brake fluid does evaporate, but not that fast!

Did you check the brake pads to see if they obsorbed the fluid? I've seen that happen on a Corvette. Caliper seals were slowely leaking but not visible leaks on the wheel or ground. The pads just sucked it up and retained the fluid. They were junk then, obviously.

BTW did about 400 miles yesterday. Rode from Ligonier to Helvetia, WV, taking all back roads passing through Ohiopyle, Parsons WV, etc. We left at 8am and got to Helvetia at lunch time for a home cooked buffet, then rode to the WV Wildlife Center to check out the wildlife, then hit up Phillipi WV to see the mummies, and finally made it home around 7pm. Perfect day and tons of insanely twisty roads. I was on my BMW R1100GS, and there was a BMW R1200GS, a BMW K1200, and a Buell 1125. I'll let you know when our next ride is.

06-11-2012, 01:55 PM
If i did that ride on the GS, you would have to pry me off the bike and find me a doner spine.

I'll check the pads tonight. Hope the caliper isnt leaking, its a PITA to find rebuild kits for these, as they are just off enough from the other 1980 models. Maybe time to put the suzuki calipers on and call it a day.

Its a 1980 CM400A Hondamatic, btw.

06-17-2012, 09:15 PM
2 odd things. First, the pads are fine, bone dry. 2nd... I think the micro cracks in the brake resivoir body are to blame. The thing is made of a transparant plastic that hasn weathered much like nay 30 year old japanese plastic. It looks wet, bit isnt, on the outside.

Given that it sat so long, that might just be it.