'72 disk brakes help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Kevin1972C20 · 09-26-2009, 03:56 PM

I have recently purchased a '72 c20 with 4 wheel disk. The truck stops but not quick and with alot of effort on the pedal. I am looking at possible bad master cylinder but this is only a guess. Pads are in good condition, rotors are clean and it doesn't pull when braking. Fluid change might help but that can't be causing the issue.
Any advice on this?

Thanks,

cparman · 09-26-2009, 03:57 PM

what kind of disc brake calipers are on the rar of the truck?

mycool72 · 09-26-2009, 04:00 PM

I believe the booster runs off a vaccum. Make sure that line is secure to the back of the carb..mine had a small leak...simply put-leak=no brakes.

Kevin1972C20 · 09-27-2009, 03:24 PM

Thanks Cool72, my vaccum line were pretty bad so I checked and was only getting -4 pressure. replaced the lines and am around -10 to -14 now. Havent check to see if that did it yet. Since the wheels are off I decided to play with the suspension a bit... who knows what I'll find.

SCOTI · 09-27-2009, 03:39 PM

Quote:

Originally Posted by Kevin1972C20

Thanks Cool72, my vaccum line were pretty bad so I checked and was only getting -4 pressure. replaced the lines and am around -10 to -14 now. Havent check to see if that did it yet. Since the wheels are off I decided to play with the suspension a bit... who knows what I'll find.

Vacuum boosters require about 16-17" minimum to be completely effective. That low vac. you indicated would definitely contribute to lower pressure being applied.

09-26-2009, 03:56 PM	#1
Kevin1972C20 Registered User Join Date: Sep 2009 Location: San Antonio, TX Posts: 15	'72 disk brakes help I have recently purchased a '72 c20 with 4 wheel disk. The truck stops but not quick and with alot of effort on the pedal. I am looking at possible bad master cylinder but this is only a guess. Pads are in good condition, rotors are clean and it doesn't pull when braking. Fluid change might help but that can't be causing the issue. Any advice on this? Thanks, __________________ -KEVIN 72 C20 402ci Last edited by Kevin1972C20; 09-26-2009 at 03:57 PM. Reason: spelling

09-26-2009, 03:57 PM	#2
cparman sharp as a marble Join Date: Jan 2007 Location: atlantic beach,florida Posts: 1,082	Re: '72 disk brakes help what kind of disc brake calipers are on the rar of the truck?

09-26-2009, 04:00 PM	#3
mycool72 Registered User Join Date: Aug 2008 Location: Mansfield, TX Posts: 309	Re: '72 disk brakes help I believe the booster runs off a vaccum. Make sure that line is secure to the back of the carb..mine had a small leak...simply put-leak=no brakes.

09-27-2009, 03:24 PM	#4
Kevin1972C20 Registered User Join Date: Sep 2009 Location: San Antonio, TX Posts: 15	Re: '72 disk brakes help Thanks Cool72, my vaccum line were pretty bad so I checked and was only getting -4 pressure. replaced the lines and am around -10 to -14 now. Havent check to see if that did it yet. Since the wheels are off I decided to play with the suspension a bit... who knows what I'll find. __________________ -KEVIN 72 C20 402ci



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