Hot Rods Manual brakes on heavy cars

With my whole engine build and with having a booster that's bad I have considered just swapping a dual master cylinder and just leaving it manual. Drums for now, front discs are in the future and possibly rear discs. How would they be? With all three variations. I had manual brakes on my mustang with disc and drums but a much lighter car and it was ok.

 

I'm running front discs/rear drums on my '38 Ford pickup with no booster. Brake pedal arm is long enough to give me a good pedal ratio. The master cylinder doesn't know or care whether the force of your foot on the brake pedal is being multiplied by a vacuum booster or mechanical leverage.

 

You could probably get by with four wheel manual drum brakes provided that they're big enough for the job, new enough to be a self-enegizing design, and you don't use some $19.00 Thunderbolt Grease Slapper brake shoes. In general I've not been too impressed with manual disc/drum brakes. The fronts do about 75% of the stopping but disc brakes aren't self-energizing.

 

I had power drum brakes on a '65 Biscayne running a 454 and 6 speed. The drums stopped great but I figured front disc would stop better. Due to the big cam, I went with a manual dual reservoir. You had to really stand on it to lock them up.

 

I would say it depends a lot on where you intend to drive. Big city metro, manual drims will cause a few pucker factors. If you do them right and have all good parts and, this is important, have the shoes arced to the drums then you should get by ok.

 

Do some research before you get too far into it. Its quite probable that manual brakes were standard on the car with PB being an option. A master cylinder for a non-power brake car would get you buy but you'll need to see if the brake pedal or the brake pedal pivot was different between power and non-power brake cars. Most of the time these were different to keep the pedal ratio adequate for each type of system.

 

Well I have gone through them all with all new parts and a new mc then discovered the booster is bad. I want to drive it everywhere. City hwy cruises

 

If you went that far and did replace all the parts , then get a booster and be done with it . You will be happy you did .
Just my opinion .

Retro Jim

 

Nobody in my area will do this anymore ... it's pretty upsetting.

 

This may kind of be a stupid question but what's the difference in single or dual digram booster? And does the diameter just a preference for clearance. The cam I believe I am going to run is kind of iffy on the power brakes

 

As said before be sure that the pedal and assembly arm is for manual brakes. Some cars use a bell crank system for power brakes and manual don't, As in my 1954 Merc I have had to change the complete pedal assembly to manual and also be sure to get a master cylinder for manual brakes as the piston size will be different. I also had a 58 ford retractable with manual drum brakes and it did just fine ( around 4,200 lbs) It would stop great from around 60 mph but the brakes would fade if you had to stop again from that speed more than once. Your galaxie in your avatar should do just fine if everything is in good shape, As they used the big drums and shoes. Power brakes was an option back then.

 

set up right you will not have a problem. i run disc/drum no booster on my '39 gmc daily, and have hauled loads over a ton without problems

 

In the past I drove many cars with manual brakes. That was all there was. Chevys, Pontiacs, Oldsmobiles. There was not one I couldn't lock the wheels at any speed if I wanted to. Keep them adjusted and in good condition and they will work. When power brakes came out the ads talked mostly about pedal pressure. Low quality linings will fade with either power or manual.

 

Power booster operation;

Rubber diaphragm seperates two chambers. Vacuum is applied to one chamber at all times, atmospheric pressure is applied to the other during brake apply. The pressure differential between atmospheric pressure (positive pressure) and vacuum (negative pressure) forces the diaphragm to move. Coupled to the diaphragm is the master cylinder rod so when the diaphragm moves the rod is applied. The greater the volume in the power booster, the better the assist is. In small diameter boosters (7, 8") there is not a lot of volume so dual diaphragm boosters w/ multiple chambers are used to increase the volume amount. A vacuum canister will also increase reserve volume. Additional volume will not correct a low vacuum (negative pressure) condition. To correct that, either increase engine vacuum or utilize a vacuum pump.

I redo a lot of brake systems. In many situations where engine vacuum is limited (base engine build) or volume is limited (not enough room for a BIG booster) it is better to run manual brakes. IMO, vacuum pumps, reservoirs, etc. are crutches, they will not help a system work as effectively as a properly designed system will work. Make sure the pedal ratio and M/C bore diameter and type are matched to your application and manual brakes will stop the vehicle very well.

If the vehicle you are working with is the one in your avatar a properly designed manual system will work fine.

Good luck.

 

I'd just get a rebuilt booster. Yeah they are expensive but the car will stop as it was meant to stop. No engineering involved. No "oh shits". bite the bullet fix it right and then you can update to discs later if you deem it necessary. You can get a used one from a reputable used parts dealer with a short warranty if you want.

My buddies 64 300 sedan stops just fine with non power stock 64 brakes. It's running a very stout 427 and he sees no need to upgrade to discs. Of course he is not road racing with it.

 

Just get you a booster and drive. What the hell is with everybody downing drum brakes. If bleed,adjusted and installed right they are just as good as the disc.On most cars with disc on front and drum on rear you will replace the front disc pads 2 times and the rear drum are still good.Most of that is caused by never adjusting the rear brakes.

 

Last time I looked at a freight train, I saw drum brakes. Good enough for me!

And, just get a rebuilt booster and get back on the road!

 

yeah but it takes miles and miles to stop a freight train also.
just for the record.i have power disc on my 52ad pick up,and non power 4 wheel drums on my el camino. when i go road racer in my elky() ,drums fade a little. just keep em adjusted right and i THINK you'll be fine

 

Where can I find the adaptor to bolt a mc to the firewall? I don't mind manual brakes just want it to stop good incase of some idiot drivers that are on the road.

 

In the early '60's there was a lining they called sintered iron. It was a metallic compuound. When that stuff started getting hot you had to ease up on the pedal (manual brakes) to keep from locking up the wheels. I don't know if there is anything that compares today, but that was good stuff. Your brake fade comes from linings, not because they are drum brakes.

 

I run manual disc/disc on my 63 C10 and I run residual valves to improve the pedal feel but I've made a few panic stops and if you push hard it stops fast. I also had a 4600 lb 65 Fury wagon with manual drums that was a testament to adequately sized drums, it stopped very well. I also believe if you understand the limits of your braking system you won't have any problems.

 

Power brakes were still an option on some really big cars well up into the 70's, then they kind of became the norm. So there are LOTS of big old cars out there with manual brakes.

 

Brake fade on drum brakes also happens because the drums get hot and expand away from the brake shoes.

 

If your cylinders have stopped pushing the shoes outward you have other problems. Any expansion will be within the range of the cylinder. Fade is a lining problem due to heat. I think there is a ceramic material they use these days.

 

I have 11x3 front 11x2.5 Drums on my galaxie
Whith Just plain asbestosfree linings the brakes
was baaaaad if you tried to stop i from 120 mph
you had to lock the wheels or the brakes faded
instantly and the linings was wasted.
Was going to instal discs but tried sintered linings
now i can brake till i want to trow up
and the hotter the brakes get the better the brakes
get
I run a Volvo 140 booster

 

If you have power stearing you can use
a hydraulic brake booster from a Olds or
Cadilac diesel and use preasure from
the ps pump

 

What happens if you get a mc with a larger than a 1 inch bore?

 

harder to push pedal.

 

My '55 F-100 stops good with a manual disk, drum set up. When I did the brakes I just went to the parts store and picked up a master cyl. for a manual brake disk/drum 70something Granada. I have a pedal assy hanging in the garage I've had since I got the truck I went to the, 'if it ain't broke don't fix it' school of hotrodding.

 

Is this for the '63 Ford in your avatar? It should stop great with a manual dual master swap. I had a few '64 Fords that stopped very well on drum brakes, but I'm anal about my brakes and everything was always new.

My last conversion to a dual-master was on my '65 Belair, I used a set up from a donor '70 Chevy and it practically fell into place and stopped well too.

Bob