general brake question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TIMINDENVER · 07-29-2002, 08:26 PM

I'm no mechanic but I think this is an easy one. I have a '68 C20 without power brakes. Currently, the brake pedal will go to the floor if I am stopped on a hill at a long light. Pumping the brakes always works. My brake fluid reservior is full. Do I need a new master cylinder? Thanks for any advice

Gordo · 07-29-2002, 08:34 PM

Yes, and soon!

TODDS 72 · 07-29-2002, 09:26 PM

WHAT GORDO SAID OR SOONER!!!

Longhorn Man · 07-29-2002, 11:18 PM

Well, lets try bleeding it and replacing all the fluid in the process. Air in the system is the first thing that will create a mushy pedal, and anyone who has ever bled brakes knows the pedal will firm up as you pump it and compress the air.
Check all your lines for moisture, you might have a loose connection someplace letting air in.

Gordo · 07-30-2002, 03:10 PM

If your sitting at a long red light with your foot on the brake and the pedal starts to sink to the floor and a pump of the pedal briefly holds again with no brake fluid loss, your master is shot! It's also called master cylinder "blow-by". Replace the master and give the system a good bleeding, replacing the old fluid is a good idea, brake fluid holds moisture. It should be flushed every two years or so but not many folks do that, (myself included).

07-29-2002, 08:26 PM	#1
TIMINDENVER Registered User Join Date: Jan 2001 Location: Denver, Colorado, USA Posts: 46	general brake question I'm no mechanic but I think this is an easy one. I have a '68 C20 without power brakes. Currently, the brake pedal will go to the floor if I am stopped on a hill at a long light. Pumping the brakes always works. My brake fluid reservior is full. Do I need a new master cylinder? Thanks for any advice __________________ 68 C20 94 K1500 ext. cab 69 Corvair Conv. 88 Mastercraft 190

07-29-2002, 08:34 PM	#2
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	Yes, and soon! __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist.

07-29-2002, 09:26 PM	#3
TODDS 72 Not the nightly winner Join Date: Jul 2002 Location: CHARLEMONT MA.USA Posts: 763	WHAT GORDO SAID OR SOONER!!! __________________ 72C10SWB BLUE 350/350 86K10LWB BLUE 5.7 700r4 7.5' fisher plow 93S10XCAB4X4 BLUE 4.3 4L60e 69gmc c10 v8 3 on the tree yellow 72k10 swb 350 3 on the tree green 86k15 swb5.0L 4spd brown

07-30-2002, 03:10 PM	#5
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	If your sitting at a long red light with your foot on the brake and the pedal starts to sink to the floor and a pump of the pedal briefly holds again with no brake fluid loss, your master is shot! It's also called master cylinder "blow-by". Replace the master and give the system a good bleeding, replacing the old fluid is a good idea, brake fluid holds moisture. It should be flushed every two years or so but not many folks do that, (myself included). __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist.

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07-29-2002, 11:18 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Well, lets try bleeding it and replacing all the fluid in the process. Air in the system is the first thing that will create a mushy pedal, and anyone who has ever bled brakes knows the pedal will firm up as you pump it and compress the air. Check all your lines for moisture, you might have a loose connection someplace letting air in.



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