Could I have boiled brake juice? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hounddogs! · 12-07-2011, 12:08 PM

So the brakes went from "getting a little soft" to "really have to plan ahead" because the rear chamber on the MC was nearly empty. I've been over the lines from front to back and don't find any liquid leaks anywhere. No seeps at the bleeders or wheel cylinders either. I did see that the rear supply line has been laying against a header tube. Could there be enough heat transfer there to cook the fluid out?

TobyArnot · 12-07-2011, 12:14 PM

I just got thru dealing with almost the same issue. "Fluid level dropping, no visible leaks. Found that M/C was leaking out the back (old dry, hard boot). Carpet pad was soaked. Replaced M/C and boot. No more lost fluid. P.S., don't overfill M/C, it can actually push fluid out the top, around the cover.

406 Q-ship · 12-07-2011, 01:00 PM

Can leaking into the vacuum booster without being seen.

hugger6933 · 12-07-2011, 01:01 PM

I've seen m/c's leakinto the booster and you can't find till the booster fills over half the way up. Pull the m/c mounting bolts and look for wetness ther. brake fluid has a fairly high boiling point I don't recall off hand what it is but I think it would be higher than a header transfer would do unless it is right at the exhuast port

hounddogs! · 12-07-2011, 03:36 PM

No booster to contend with, but I will see what the MC looks like when it's demounted.

Longhorn Man · 12-07-2011, 07:25 PM

No booster... NO need to remove it to look. Just look inder the dash where the brake push rod goes through the firewall.
You'll want to move that brake line at least an inch from the header. I personally try for at least two inches.
Posted via Mobile Device

hounddogs! · 12-07-2011, 08:32 PM

Quote:

Originally Posted by Longhorn Man

You'll want to move that brake line at least an inch from the header. I personally try for at least two inches.
Posted via Mobile Device

Well crap. I was doing well to get it 1/4" off the tube.

cleszkie · 12-07-2011, 08:55 PM

Has the brake line been routed next to the header for a long time, and has the problem just started? If so, I don't think its a heat issue if its been working OK for this long. Sounds like a leak or really worn or broken brake linings. When the shoes are really toast, the brake pistons need all the fluid they can get to spread the shoes enough to contact the drum. This can empty the MC reservoir.

If you just installed the headers next to the brake line, then maybe heat is the culprit, but I doubt it. Good luck.

hounddogs! · 12-07-2011, 11:41 PM

Brake lines have been near the header for awhile. I was kind of grasping at straws there. Worn shoes would make sense-thanks for a new path to check out.

12-07-2011, 12:08 PM	#1
hounddogs! Restoring it $200 at a time... Join Date: Aug 2008 Location: NE Kansas Posts: 886	Could I have boiled brake juice? So the brakes went from "getting a little soft" to "really have to plan ahead" because the rear chamber on the MC was nearly empty. I've been over the lines from front to back and don't find any liquid leaks anywhere. No seeps at the bleeders or wheel cylinders either. I did see that the rear supply line has been laying against a header tube. Could there be enough heat transfer there to cook the fluid out? __________________ Charter member of the 'Put the dimmer switch back on the damn floor where it belongs' Society '68 5.3L-4 speed LWB C20; grandpa bought it for the farm in '71. Now LS 5.3, rather than 327. DD '09 Pilot Weekender '65 Skylark 300-4V-4 speed Wife's '07 Lexus ES350; 117 actuator motors and I can't see the engine. Son's '04 F250 SuperCab 6.0

12-07-2011, 12:14 PM	#2
TobyArnot Quit if it's not FUN!!! Join Date: Jul 2010 Location: Indian Trail, N.C, Posts: 864	Re: Could I have boiled brake juice? I just got thru dealing with almost the same issue. "Fluid level dropping, no visible leaks. Found that M/C was leaking out the back (old dry, hard boot). Carpet pad was soaked. Replaced M/C and boot. No more lost fluid. P.S., don't overfill M/C, it can actually push fluid out the top, around the cover.

12-07-2011, 01:00 PM	#3
406 Q-ship Registered User Join Date: Oct 2010 Location: Largo Florida Posts: 632	Re: Could I have boiled brake juice? Can leaking into the vacuum booster without being seen. __________________ Lifes journey is not to arrive at the gate well preserved, it is to slide in sideways all used up and wore out yelling.....God what'a ride! Where patience fails, force prevails Stapp's Ironical Paradox "The universal aptitude for ineptitude makes any human accomplishment an incredible miracle."

12-07-2011, 01:01 PM	#4
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,279	Re: Could I have boiled brake juice? I've seen m/c's leakinto the booster and you can't find till the booster fills over half the way up. Pull the m/c mounting bolts and look for wetness ther. brake fluid has a fairly high boiling point I don't recall off hand what it is but I think it would be higher than a header transfer would do unless it is right at the exhuast port

12-07-2011, 03:36 PM	#5
hounddogs! Restoring it $200 at a time... Join Date: Aug 2008 Location: NE Kansas Posts: 886	Re: Could I have boiled brake juice? No booster to contend with, but I will see what the MC looks like when it's demounted. __________________ Charter member of the 'Put the dimmer switch back on the damn floor where it belongs' Society '68 5.3L-4 speed LWB C20; grandpa bought it for the farm in '71. Now LS 5.3, rather than 327. DD '09 Pilot Weekender '65 Skylark 300-4V-4 speed Wife's '07 Lexus ES350; 117 actuator motors and I can't see the engine. Son's '04 F250 SuperCab 6.0

12-07-2011, 07:25 PM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Could I have boiled brake juice? No booster... NO need to remove it to look. Just look inder the dash where the brake push rod goes through the firewall. You'll want to move that brake line at least an inch from the header. I personally try for at least two inches. Posted via Mobile Device

12-07-2011, 08:55 PM	#8
cleszkie Registered User Join Date: Feb 2003 Location: Santa Ana, CA Posts: 2,191	Re: Could I have boiled brake juice? Has the brake line been routed next to the header for a long time, and has the problem just started? If so, I don't think its a heat issue if its been working OK for this long. Sounds like a leak or really worn or broken brake linings. When the shoes are really toast, the brake pistons need all the fluid they can get to spread the shoes enough to contact the drum. This can empty the MC reservoir. If you just installed the headers next to the brake line, then maybe heat is the culprit, but I doubt it. Good luck.

12-07-2011, 11:41 PM	#9
hounddogs! Restoring it $200 at a time... Join Date: Aug 2008 Location: NE Kansas Posts: 886	Re: Could I have boiled brake juice? Brake lines have been near the header for awhile. I was kind of grasping at straws there. Worn shoes would make sense-thanks for a new path to check out. __________________ Charter member of the 'Put the dimmer switch back on the damn floor where it belongs' Society '68 5.3L-4 speed LWB C20; grandpa bought it for the farm in '71. Now LS 5.3, rather than 327. DD '09 Pilot Weekender '65 Skylark 300-4V-4 speed Wife's '07 Lexus ES350; 117 actuator motors and I can't see the engine. Son's '04 F250 SuperCab 6.0



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