The Stovebolt Site Forums The Shop Area The HiPo Shop Front Discs/Rear Drum - But Power or Manual?

I am wondering if I will "want" power brakes once I upgrade to front discs. I currently have the standard un-assisted drum brakes and I don't plan to haul or tow anything with the truck. It will just be a daily driver. It's a '57 1/2 ton.

I do plan to change to a split system master cylinder for safety and I want to keep my stock pedal, so it will be an on the frame installation.

Based on other posts, it seems residual & proportioning valves can create installation & bleeding issues. I suspect I will still need a proportioning valve. True?

I guess the main reason I'm thinking of un-assisted is their lower cost, but since the master cylinder & mounting bracket I'll need are specific to power assisted or not, I thought I get some opinions now.

Eric
'57 Stepside
"Go Wings"

Just from my own experience with non-assisted disks on a truck ('79 Dodge Warlock), you'll definetly be happier with power assist. Seems that disks really need some boosting to really be effective, as there is no self energizing like found in drums.

I just purchased a double boost system for my 46 and I've been trying to find out what goes with it. From what I can make out it needs a proportioning valve which hooks up to the master cylinder, a 2 lb residual valve for the front disks and a 10 lb for the rear drums. I,m not sure but if you put a manual adjusted metering valve in the rear system (like most hotrodders do) than you don't require the metering valve on the master cylinder. Problem is then you have to manually adjust the rear valve to set up the proportion of pressure to the rear brakes so they won't lock up rather than letting the proportioning valve hooked up to the master cylinder do the work. There a little pricey but I'm going with the proportioning valve on the master cylinder. If you look on the master cylinder of any modern day Chevy than you'll see the valve hooked to it. Safety is a big concern and why adjust it when you can let it work automatically. There's a potential for leaks because of the many joints but if you take your time installing the lines than it should be all right. Good luck Bob.T

The best way to go is to buy a system. Tell the supplier what you want to do. IE: disc front & drum rear with the booster/master mounted under the floor. I have done several of these and used a 8" dual diaphram booster with a dual master and a proportioning valve. My supplier installs the residual valve in the MC.
Lots of opinions on this subject but this has worked best for me and my customers are happy.
Fred

Well I'll throw my 2 cents into the mix on this one.

Disc brakes will work without a power assisted master cylinder. You would need to go with a 1 inch bore on the master to generate more pressure. Powered systems usually use a 1 1/16 master cylinder.

I am planning to put 4 wheel non-powered disc brakes on my 1940 gmc. I don't want the extra vacuum line to hook up.

Last week I ordered a complete front disc brake kit for my 1959 GMC 1/2 ton from The Filling station. This is a 6 lug disc brake kit with 12 inch rotors and master cylinder with booster and metering valve. The kit was priced right at $699. I will have to get some roller bearings now for the original hub for another $150 or so, bend some lines, etc. I chose to go with the power disc brakes on this truck because it has factory power steering. I thought it would be nice to add that option.

I've got an unassisted disk/drum setup on my '55 1st Suburban. If my wife were going to drive it I'd put power assist on it. Just for me, its fine as is.

For myself I'd look at power steering before I worried about power brakes.

I have two trucks a 55 and a 65.Both are disc front drum rear brake setups.The 55 has a power unit and the 65 does not.The only difference that I notice is that you have to use a little more foot pressure without the power assist.On my 55 I bought a dual power master cyl. from Chevy Duty,( different name now) that mounts in the same position as the original Master cyl.on the frame rail under the floor.Everything was included and it was an easy install.Of course it was a little pricey,but sometimes its better to pay a little more and get something that fits right up.Just my 2 cts.worth.If you go with the powetr unit,make sure you hook up the vacuum line directly to the intake manifold.