72 c/10 brake question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

miklgeo72 · 10-03-2004, 09:39 PM

1st time posting question. will a 72 3/4 ton brake setup (master cyl.-booster-prop. valve)work in my 72 1/2 ton? It all looks identical except for the master cyl., where the smaller reservoir in the 3/4ton is in the front.Are they compatible? and if so do i need to adjust my lines front to back? i am a complete rookie in this area so any advice is helpfull. thanks

big blue 72 · 10-03-2004, 10:10 PM

welcome from Ohio. sorry i cant answer your Q. somebody will though.

Longhorn Man · 10-03-2004, 10:24 PM

First of all, welcome to the board from central Ohio. What's the details of your 72?

I wouldn't use the master cylinder. They are less than 20 bucks at the parts store, and as you noted, the 3/4 ton unit is not the same as 1/2 ton.
If I am reading into this properly,. it sounds like you wish to add power brakes, if this is the case, all you need is the booster and assorted hardware. The proportioning valve and master cylinder are the same from power assist to manual.

miklgeo72 · 10-04-2004, 05:08 AM

thanks for the welcomes, to answer the question i allready have power brakes,but my booster went out,and the proportioning valve has never been problem free,so i priced the two items at over $200.00 for replacement.A buddy took pity on me, went home to his wrecked 3/4ton snipped the lines coming out of the prop. valve ,unbolted the booster from the firewall with the master cyl. still inbetween and said "here you go it will bolt right in".But since stopping is an important part of driving I should probebly stop trying to penny-pinch, and spend the $200.00 for the rebuilt parts.thanks again.

Longhorn Man · 10-04-2004, 10:25 AM

nothing wrong with used parts. $200 is a lot of money.

*chevytruckfan* · 10-04-2004, 12:45 PM

Each unit was made to work as a system. If you have the booster, MC, and valve they will all work together. Between the valve and the brakes the lines and hoses just move fluid through the system. So a 3/4 ton and 1/2 ton are not what you need to look for. What you need is to keep the type of system. Is is a drum/drum, disk/drum, or disk,disk? A disk system takes more fluid than a drum. If your MC from the 3/4 is a drum/drum and the 1/2 ton is disk/drum that is why the donor MC will have a smaller resivoir and don't use it. IF the systems are the same disk/drum and disk/drum then you can use it like your friend said. If not get the replacement parts for your system.

Longhorn Man · 10-04-2004, 12:57 PM

The smaller reservoir that is in the rear on the 1/2 ton controls the rear brakes. On the 3/4 ton (and one ton0 the smaller reservoir is in the front, and it controls the rear brakes. The lines are swapped front for back, and if not mistaken, the fittings are different sizes.

miklgeo72 · 10-04-2004, 03:57 PM

You guys seam to be clearer, and have more knowledge on this subject than my Chilton's or Hayes manuals. thanks.

10-03-2004, 09:39 PM	#1
miklgeo72 Registered User Join Date: Oct 2004 Location: north.cal Posts: 3	72 c/10 brake question 1st time posting question. will a 72 3/4 ton brake setup (master cyl.-booster-prop. valve)work in my 72 1/2 ton? It all looks identical except for the master cyl., where the smaller reservoir in the 3/4ton is in the front.Are they compatible? and if so do i need to adjust my lines front to back? i am a complete rookie in this area so any advice is helpfull. thanks

10-03-2004, 10:10 PM	#2
big blue 72 Senior Member Join Date: May 2002 Location: hamilton,ohio,usa Posts: 1,499	welcome from Ohio. sorry i cant answer your Q. somebody will though.

10-03-2004, 10:24 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	First of all, welcome to the board from central Ohio. What's the details of your 72? I wouldn't use the master cylinder. They are less than 20 bucks at the parts store, and as you noted, the 3/4 ton unit is not the same as 1/2 ton. If I am reading into this properly,. it sounds like you wish to add power brakes, if this is the case, all you need is the booster and assorted hardware. The proportioning valve and master cylinder are the same from power assist to manual.

10-04-2004, 05:08 AM	#4
miklgeo72 Registered User Join Date: Oct 2004 Location: north.cal Posts: 3	thanks for the welcomes, to answer the question i allready have power brakes,but my booster went out,and the proportioning valve has never been problem free,so i priced the two items at over $200.00 for replacement.A buddy took pity on me, went home to his wrecked 3/4ton snipped the lines coming out of the prop. valve ,unbolted the booster from the firewall with the master cyl. still inbetween and said "here you go it will bolt right in".But since stopping is an important part of driving I should probebly stop trying to penny-pinch, and spend the $200.00 for the rebuilt parts.thanks again.

10-04-2004, 10:25 AM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	nothing wrong with used parts. $200 is a lot of money.

10-04-2004, 12:45 PM	#6
chevytruckfan Account Suspended Join Date: May 2004 Location: Lake Placid, Florida Posts: 930	Each unit was made to work as a system. If you have the booster, MC, and valve they will all work together. Between the valve and the brakes the lines and hoses just move fluid through the system. So a 3/4 ton and 1/2 ton are not what you need to look for. What you need is to keep the type of system. Is is a drum/drum, disk/drum, or disk,disk? A disk system takes more fluid than a drum. If your MC from the 3/4 is a drum/drum and the 1/2 ton is disk/drum that is why the donor MC will have a smaller resivoir and don't use it. IF the systems are the same disk/drum and disk/drum then you can use it like your friend said. If not get the replacement parts for your system.

10-04-2004, 12:57 PM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	The smaller reservoir that is in the rear on the 1/2 ton controls the rear brakes. On the 3/4 ton (and one ton0 the smaller reservoir is in the front, and it controls the rear brakes. The lines are swapped front for back, and if not mistaken, the fittings are different sizes.

10-04-2004, 03:57 PM	#8
miklgeo72 Registered User Join Date: Oct 2004 Location: north.cal Posts: 3	You guys seam to be clearer, and have more knowledge on this subject than my Chilton's or Hayes manuals. thanks.



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