Thread: Who has replaced front drums with discs and no power brakes---and ran them??

Tweet

I am getting ready to install disc brakes on the front of my RPU to replace the tired 40 Ford drum brakes. Rear brakes will still be stock S10 drums. I do not have power brakes, just a standard Corvette double chamber master cylinder under the floor. Who has done this, and what difference did you see in stopping ability and required pedal pressure? Please---no theoretical answers---I want to hear from people who have actually made this change and driven their car---with no power brake booster.---Brian

I converted from manual front drums in my Chevelle with a 454 (3800lbs)to manual front discs. Stopping ability was greatly improved, pedal pressure was about the same "lots of pedal pressure". So then I changed over to power. Changed the master cylinder to a power unit and booster. Stopping is the same but much, much less pedal pressure.

You probably won't have as much pedal presuure because your is considerably lighter. I have a 51 Ford Rat Rod with 11" Chevy discs in front and 10 bolt Chevy rear. I'm using the manual Corvette front disc master I took out of my Chevelle. It stops good and not too much pedal pressure because of the lighter weight.

Just remember that a liitle pedal ratio makes a BIG differance

Ive never converted from drum to disc, but i personaly like the feel i get with no power booster. I ran the merc with a camaro subframe with discs , but i left out the power brakes it stopped fine with little pressure.

Ran discs on many cars with no power booster, even on all four wheels... As Jerry mentioned, pedal ratio is important as is the size of the master cylinder. On a light car with disc front, drum rear, a 7/8" or 1" cylinder with the appropriate residual valves and probably an adjustable proportioning valve will work fine... I do, however, always check and set my brakes on a new build using brake pressure gauges to balance the fluid pressure at the wheels...

My 34 Plymouth has disc up front with no power boost. Takes a bit of pedal to haul it down from normal cruising speed but it does it and with no fade. Of course, it also helps that I have discs in the rear as well. I think you'll like the conversion if done right.

Dave is there a good book or place to read up on this.
This is also the first time I've built a brake system
from scratch, and I would very much like to get it right.
And need to learn about the right proportioning valves
and what to use to check the presure and how.
Thanks Kurt

We have 4 wheel disk on the Model A and no power. It stops fine, good pedal feel too.
Larry

i converted my chevelle no power brakes works good stoping at 130

Originally Posted by vara4

Dave is there a good book or place to read up on this.
This is also the first time I've built a brake system
from scratch, and I would very much like to get it right.
And need to learn about the right proportioning valves
and what to use to check the presure and how.
Thanks Kurt

Brake pressure gauges to check the pressure. Lots of the dirt track supply places sell them...Speedway has them for sure. Here's a site with some good brake and suspension information.....



http://www.hotrodders.com/kb/suspension-brakes-steering

Thanks Dave For the Info. Kurt

The 55 has disc/drum & no power. Stops fine. No choice w/ 4" of vacuum.

The 32 has disc/drums & a booster under the dash (Kugel 90 degree unit) & stops waaaay better.

I wouldn't worry about it.. 40 Ford brakes don't self energize so there is no mechanical advantage on them like there is on self energizing drums, and there is no mechanical advantage on a disc brake system.. so the braking effort will be the same, just you will stop faster due to the more efficent brakes

I have a 54 Ford that I converted to manual disc brakes in the front. At the same time I changed the rear brakes to a wider shoe/drum. This is a very heavy car, much more weight than yours. I used a non-power disc brake master cylinder (two bowl).

I am very happy with this setup. Yes, the pressure required is more than with a power brake setup, but less than the old drum brakes on all four wheels. I had a major emergency requiring to me slam on the brakes doing 65 mph on an interstate and the brakes came through with flying colors (it stopped the car quickly and without hitting anything.)

So---Today I ordered up a complete front disc brake set-up for the roadster pickup, from Hortons in Milton. Rotor & hub combination, calipers, pucks, brackets to mount calipers, bearings, spindle bearing adapters, and requisite nuts and bolts. This is to go on '40 Ford spindles which are currently running '40 drums and shoes. and the price for purchase, Goods and Service tax, sales tax, and shipping??--Step back---step way back----$874.00. Yeeouch!!! Damn that hurt...