disappearing brake fluid

dynamic88 · 07-28-2007, 01:23 AM

i have a 65 olds dynamic 88 convertable. last year i replaced all the brakes from the master cylinder down to the brake cylinders. the lines were bled off and everything. on two seperate occassions i have went to pull the car out of the garage and did not have any brakes. when i checked the master cylinder i found it to be empty wheni filled it up i had brakes again. i have checked the brake cylinders, the lines there are no signs of a leak. any suggestions on where it might be going. thanks chris

bjtstarfire · 07-28-2007, 04:17 AM

The fluid might be leaking past the master cyl gaskets and into the pwr brake booster. Did you rebuild the master cyl. When you did your repairs? If the inside bore is scored or rusted (brake fluid can absorb water…) you can have a problem where a bad seal is compromised.

Not sure if you have pwr brakes or not.

BTW:
It may have leaked out a line of brake cyl. and evaporated to the point where you have no trace of it...

Ben

dynamic88 · 07-28-2007, 06:02 AM

the master cylinder is new. yes i have power brakes. it would have to one hell of an evaporaton. i work on that car every day, so i think i would have seen a puddle before it could evaporate. i also am using sylicone brake fluid. a car buff suggested i use that since i replaced everything. he says its beter in the old cars since they dont get used as much. chris

dynamic88 · 07-28-2007, 06:04 AM

the only thing i have not checked was the power booster. there is nothing coming in through the brake pedal or down the firewall. so i dont know.

bjtstarfire · 07-28-2007, 08:25 AM

The booster can hold a lot of fulid prior to it getting to a point where it will leak down the firewall.

I hope you track it down and keep us posted on your progress.

I was going to use the sylicone fluid in mine after my rebuild but for some reason I did not, I hope that was not a long term mistake on my part.

J-(Chicago) · 07-28-2007, 01:41 PM

I had this happen as well. I lined my whole garage floor in rosin paper hoping for a drop to surface. Nothing for a week or so. Finally 1 magical day a drop surfaced on the driver side right behind/underneath the driver door. There was a splice in the line that only leaked when brakes were applied. the fluid would sit up and behind the frame rail and dry up from the wind on the highway on the way home.

dynamic88 · 07-28-2007, 02:09 PM

ill take a closer look at the booster and the frame rails, but with as much as i have lost and it not going any where but from the garage to driveway back to the garage. i would think i should have noticed something. thanks for the info. chris

keith6989 · 07-28-2007, 05:29 PM

I looked for days for my leak, it turned out that i didn't tighten a bleed valve all the way and there was a hairline crack in the brake line that ran into a cross member thing and you couldn't find either one so I would start at the brake booster and work my way out, and double check everything since they are the most important things on the car.

Good luck finding your prob.

dynamic88 · 07-28-2007, 08:04 PM

thanks, i think. ive been over it once ill have to go over it again and double check everything.

07-28-2007, 01:23 AM	#1 (permalink)
dynamic88 Senior Member Join Date: Oct 2006 Posts: 138	disappearing brake fluid i have a 65 olds dynamic 88 convertable. last year i replaced all the brakes from the master cylinder down to the brake cylinders. the lines were bled off and everything. on two seperate occassions i have went to pull the car out of the garage and did not have any brakes. when i checked the master cylinder i found it to be empty wheni filled it up i had brakes again. i have checked the brake cylinders, the lines there are no signs of a leak. any suggestions on where it might be going. thanks chris

07-28-2007, 04:17 AM	#2 (permalink)
bjtstarfire Member Join Date: Nov 2006 Location: Greater Philadelphia, PA area Posts: 64	The fluid might be leaking past the master cyl gaskets and into the pwr brake booster. Did you rebuild the master cyl. When you did your repairs? If the inside bore is scored or rusted (brake fluid can absorb water…) you can have a problem where a bad seal is compromised. Not sure if you have pwr brakes or not. BTW: It may have leaked out a line of brake cyl. and evaporated to the point where you have no trace of it... Ben __________________ Ben '61 Starfire

07-28-2007, 08:25 AM	#5 (permalink)
bjtstarfire Member Join Date: Nov 2006 Location: Greater Philadelphia, PA area Posts: 64	The booster can hold a lot of fulid prior to it getting to a point where it will leak down the firewall. I hope you track it down and keep us posted on your progress. I was going to use the sylicone fluid in mine after my rebuild but for some reason I did not, I hope that was not a long term mistake on my part. __________________ Ben '61 Starfire

07-28-2007, 01:41 PM	#6 (permalink)
J-(Chicago) Seasoned beater pilot. Join Date: Jan 2007 Location: Chicago Posts: 1,380	I had this happen as well. I lined my whole garage floor in rosin paper hoping for a drop to surface. Nothing for a week or so. Finally 1 magical day a drop surfaced on the driver side right behind/underneath the driver door. There was a splice in the line that only leaked when brakes were applied. the fluid would sit up and behind the frame rail and dry up from the wind on the highway on the way home. __________________ I'd rather have a numbers matching poker hand.

07-28-2007, 05:29 PM	#8 (permalink)
keith6989 2Blue 55" Join Date: Dec 2006 Location: Nova Scotia, Canada Posts: 377	I looked for days for my leak, it turned out that i didn't tighten a bleed valve all the way and there was a hairline crack in the brake line that ran into a cross member thing and you couldn't find either one so I would start at the brake booster and work my way out, and double check everything since they are the most important things on the car. Good luck finding your prob. __________________ Robert 1955 Oldsmobile Super 88

07-28-2007, 06:02 AM	#3 (permalink)
dynamic88 Senior Member Join Date: Oct 2006 Posts: 138	the master cylinder is new. yes i have power brakes. it would have to one hell of an evaporaton. i work on that car every day, so i think i would have seen a puddle before it could evaporate. i also am using sylicone brake fluid. a car buff suggested i use that since i replaced everything. he says its beter in the old cars since they dont get used as much. chris

07-28-2007, 06:04 AM	#4 (permalink)
dynamic88 Senior Member Join Date: Oct 2006 Posts: 138	the only thing i have not checked was the power booster. there is nothing coming in through the brake pedal or down the firewall. so i dont know.

07-28-2007, 02:09 PM	#7 (permalink)
dynamic88 Senior Member Join Date: Oct 2006 Posts: 138	ill take a closer look at the booster and the frame rails, but with as much as i have lost and it not going any where but from the garage to driveway back to the garage. i would think i should have noticed something. thanks for the info. chris

07-28-2007, 08:04 PM	#9 (permalink)
dynamic88 Senior Member Join Date: Oct 2006 Posts: 138	thanks, i think. ive been over it once ill have to go over it again and double check everything.

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