1/2 ton or 3/4 ton brake cylinder booster

[Ricks1971]

I am converting my 67 to disc brakes and also upgrading the rear to disc brakes too. My question is should I use a 1/2 ton or 3/4 ton brake booster?

[lolife99]

I would just use a 71-72 1/2-ton booster, master cylinder and prop valve.
I'm not sure there is much difference.
Many people use aftermarket boosters.

[andrewmp6]

Just make sure its for disc front and rear you should be fine.

[Rochlow]

Originally Posted by lolife99

I would just use a 71-72 1/2-ton booster, master cylinder and prop valve.
I'm not sure there is much difference.
Many people use aftermarket boosters.

Plus, these can be bought from local parts stores for around $150 as opposed to $299-399 for CPP or other aftermarket brands.

[Gus350]

Do you even really need the booster if your going for a clean firewall look. How do they perform without one?

thanks. Kevin

[lolife99]

Originally Posted by andrewmp6

Just make sure its for disc front and rear you should be fine.

I missed the rear disc brake part.

You may need to purchase a rear disc specific prop valve from an aftermarket source.
Some disc brake kits have you disassemble and modifiy the stock prop valve.
Some people don't run a stock prop valve.
They run an adjustable prop valve installed in the rear disc brake line.

[lolife99]

Originally Posted by Gus350

Do you even really need the booster if your going for a clean firewall look. How do they perform without one?

thanks. Kevin

There is more pedal effort without the booster,... but I think it's worth the look.
It's just something you have to get use to,...

[Jonboy]

Originally Posted by lolife99

I missed the rear disc brake part.

You may need to purchase a rear disc specific prop valve from an aftermarket source.
Some disc brake kits have you disassemble and modifiy the stock prop valve.
Some people don't run a stock prop valve.
They run an adjustable prop valve installed in the rear disc brake line.

Keith, what do you need to do to modify the stock prop valve? I am thinking about running 4 wheel discs on my '74. As much info as I have been devouring the last couple of days, my head is swimming now.....

[lolife99]

Originally Posted by Jonboy

Keith, what do you need to do to modify the stock prop valve? I am thinking about running 4 wheel discs on my '74. As much info as I have been devouring the last couple of days, my head is swimming now.....

I have not done this mod my self.

Look here at the picture:
http://www.classicperform.com/Instru...structions.pdf

Notes:
This modification will disable the proportioning valve on a disc drum combination
valve and convert it to a disc disc type combination valve.

Instructions:
1. Remove the hex shaped proportioning valve assembly from the rear of
the combination valve. See the illustration to identify the different parts
of the combination valve.

2. Using a thin set of pliers, carefully reach inside the combination valve
and remove the small rubber piston from the isolation valve. This will
disable the proportioning valve.

3. Reinstall the hex shaped proportioning valve assembly into the combination
valve.

4. Double check that the proportioning valve has been tightened correctly,
and that there are no leaks.

[Daaaanz67]

X2 on what lolife said.
Posted via Mobile Device

[LONGHAIR]

Originally Posted by Gus350

Do you even really need the booster if your going for a clean firewall look. How do they perform without one?

thanks. Kevin

If you are really set on the clean firewall look, there are better ways to go than removing the booster. The increased peddle effort required is bad enough in cars, it would be worse in a truck.....and 4 wheel disc would probably be unstoppable.
"Power brakes" came along because of discs. While they are better in several ways, peddle effort vs. stopping power is not one of them, you need the booster.

There are "remote booster" kits available for many applications. This puts the booster behind the dash or under the floor, but leaves the master cylinder alone.
There is also a set-up that puts the booster and master cylinder together behind the dash. It is an angled bracket that mounts them parallel to the firewall, in the cab. This eliminates the whole thing from the engine compartment.

[wraprail]

Originally Posted by Gus350

Do you even really need the booster if your going for a clean firewall look. How do they perform without one?

thanks. Kevin

I have used manual (no power booster) 4 wheel disc brakes for the last 13 years, on two differant C10s.

First with a corvette master and now with a chrysler master.

With the correct Master Cylinder bore and the right pedal ratio the effort required to stop is not much more than power brakes. Mine is even less than the factory manual disc/drum brakes that came on these trucks.

I tow a double axle car trailer with a 3200 pound car on it and have no problem stopping it. And right now the trailer brakes are not working.

Most all race cars in most forms of racing these days have 4 wheel disc and don't use a brake booster.

[LONGHAIR]

Originally Posted by wraprail

Most all race cars in most forms of racing these days have 4 wheel disc and don't use a brake booster.

That is a completely unfair analogy. Those racecars are sporting huge diameter rotors and have very aggressive pad compounds. These are not only prohibitively expensive but the would be eaten up in daily street driving.

[Bigdav160]

I'm with Longhair on this. Disc brakes need power assist.

I own two Corvettes. One with power assist, one without. There's a big difference in braking power.

[68 TT]

Originally Posted by lolife99

I missed the rear disc brake part.

You may need to purchase a rear disc specific prop valve from an aftermarket source.
Some disc brake kits have you disassemble and modifiy the stock prop valve.
Some people don't run a stock prop valve.
They run an adjustable prop valve installed in the rear disc brake line.

I just put this new Wilwood adjustable prop valve into my Camaro. It has the same configuration and bolt pattern as the common GM valve but also incorporates the adjustment knob for dialing in your brakes. Great idea.

http://www.summitracing.com/parts/wi...1179/overview/

[68 TT]

Originally Posted by Bigdav160

I'm with Longhair on this. Disc brakes need power assist.

I own two Corvettes. One with power assist, one without. There's a big difference in braking power.

x3

Power brakes are a must with a heavy truck.

Another option is a 1-ton truck hydra-boost conversion rather than a vacuum booster setup.

[Ricks1971]

All I really wanted to know if I should use a 1/2 ton or 3/4 ton booster on my 67 C10? LOL