[Danspeed1]

Hello,

I've been driving my 55 Chevy a little bit, finally, and its been a lot of fun, but I just can't get over the brakes. I'm not new to pre-1970's cars, but I just can't get over how insecure the brakes make me feel. I have no seat belts... So it still has the stock brake setup, single master, and drums on all four corners. I was driving yesterday and can't seem to get used to the long throw of the brake pedal. Also I noticed unless I really pump the brakes the pedal is on the floor. At one point I had the pedal pinned against the firewall and the car was still rolling until I pumped the brakes. Something definitely wrong. Anyway, I would like to replace my single master cylinder with a dual for piece of mind. As of right now my plan is to keep the front and rear drums. Prior to this I had a 46 Chevy with a dual master that I daily drove and I found the drums to be more than adequate for daily use. Its 6 cylinder car with stock rear. I haven't had the drums apart yet but I was wondering if the wheel cylinders in the front are larger than the rear or if they were all about the same size. I have been doing a lot of reading online and it seems the master of choice is out of a 68 Chevelle; but there seems to be so much mixed information on whether its best to do a proportioning valve, as well as whether or not you need a residual check valves or not? (are they built into the 68 master cylinder?) I would like the car to stop straight with moderate pedal effort and a shorter throw. My plan is a higher hp v8 for the future...

Thanks for the input,

Dan

 

[mech393]

if you don't get an answer here go to a chevelle web site and see if they have a manual section there in the brake section there should be the information your looking for as far as your brakes going to the floor have you checked the brake shoe to drum contact, it maybe out of adjustment or frozen up.

 

[zbad55]

If I were you I would just get the complete Chevelle brake setup with rotors, caliper's, m/C and prop valve. Using this setup allows you to use the stock spindle, you just need to add a bracket to mount the calipers. Keep the rear drums and just check to make sure the wheel cylinders are good, but I would just replace them and all the rear drum hardware. For me when it comes to safety I just wouldn't mess around. The chevelle setup can be done relatively inexpensive and they work great. I've been running this way for 18 years now and not any issues.

 

[carls 56]

power (is great) drums (don't have to have disc), dual mc and proportioning valve, you will be good to go. :anim_25:

 

[Jim '57]

Sounds like you may have air in the lines if when you pump them they build up higher.
I put a dual MC and booster on my El Camino and kept the drums all around and it stops very well with little pressure.
Jim

 

[stans 57]

Holy Moses man! Have you checked the brake fluid level lately? Or bothered to adjust the brakes in the last 20 years? Seriously, everything needs some maintainence once in a while....you didn't mention any so I guess the car didn't get any, a common problem.

Stan

 

[Danspeed1]

Thanks for the responses. To answer a couple of the questions, the wheel cylinders are less than 5 years old but the rest of the braking system is original. I agree 100% it certainly needs maintenance. I plan to plum brand new lines and maybe even hoses, I figured this would be the perfect time to upgrade to a dual master for the added safety. My last car of the pre-1960 era was a 1946 Chevy Stylemaster. It was a great car and a lot of fun to drive. It was also harder to drive than this 55. This 55 is a dream in comparison. I spent 2 years commuting daily in it with a 216, then on the second year a 235, manual brakes with drums on all 4 corners. I personally liked the transmission of brake feel of the manual brakes, and never felt unsafe in that car even at highway speeds which amounted to the majority of my 30 mile commute. The only upgrade was a dual master cylinder and if I remember correctly the guys on the other boards were using ones from a ford. I could probably get away with the same swap and be very happy but I know from experience its better to ask on here for the tried and true solution.

What I take from the posts so far is there is no right way to do this. I can use a dual master with or without a booster with or without a proportioning valve, with or without residual valves.

DG

 

[pistoncan]

Myself and several others have posted this info several times on tri five, but we will do it again.

You need to get a rebuilt 67 camero dual master cylinder for drum brakes. 67 was the changeover year and they made them with both drum brakes and disc brakes. Make sure it is the one for the drum/drum brakes.

I think they are 37 dollars from O Riley's

a 6 ft length of brake line,
a union
a flair plug.

Disconnect the brake like that comes out of the right front wheel T to the rear wheels and install the plug in the T. Your front brakes are now isolated.

Add the union to the brake line that goes to the rear wheels.

Add the 6 ft brake line to the union and run it along the frame next to the line that goes to the front wheels, up to the master cylinder. This is now your rear brake line system.

Install the master cylinder and add the adapters to go down to the size of your brake lines.

Attach the brake lines to the master cylinder and bleed the system.

You are done. You do not need a proportioning valve

The system works like it always did except you have a safety backup in case of a brake line or wheel cylinder failure.

I have done probably a dozen of these systems over the years and every one has worked fine.

Best 50 dollars you ever spent on your car.

P.S. Proportioning valves are necessary because drum brakes and disc brakes have different volume requirements to operate together. On a car with drum/drum brakes all brakes use the same volume and no proportioning valve is needed.

 

[timbo56]

Thanks for the responses. To answer a couple of the questions, the wheel cylinders are less than 5 years old but the rest of the braking system is original.
DG

Have you checked your wheel cylinders lately, it sounds like you have a leak on one (or a pipe) if you are pumping the pedal, age has nothing to do with the quality. On one of my cars I went through at least two sets of rear wheel cylinders in as many years until I changed back to OEM parts.
On my 55 despite having a slight MC leak the brakes are still rock hard.

 

[Danspeed1]

One more question if someone can please clarify the misinformation I am reading else where. I read that although all of the stock masters came with residual pressure valves on vehicles with drum brakes front and rear, during the re manufacturing process many manufacturers remove these valves. How do I know if I have the right parts in my master or if I need to add a set of aftermarket ones?

Dan

 

[billds56ht]

Dan do yourself a favor and take Zbads advise. To much time labor and money in to these cars to take a chance. Power front disc brake conv can be had for appx 500.00 to 600.00. How much would a front fender cost? Good luck Bill.

 

[55sam]

Residual valves are only necessary if the m/c is below the level of the wheel cylinders(as in mounted under the floor).

I seriously suggest you consider at LEAST a manual disc/drum changeover. Cheap life insurance! Complete AFFORDABLE kits are available from Danchuk and other reputable suppliers. pistoncan obviously knows what he's talking about if you decide to stay all drum. Good luck with whatever you decide.

 

[MikeMiloserdoff]

I commend you (not condemn you, LOL) for looking at the braking system before looking at the horsepower system, I do the same type of thinking. In 1957, with the advent of the 283 Rochester Fuel Injection engine, the motto was "One Horsepower Per Cubic Inch" (283 CID engine turning out 283 HP). In one of the reviews of the 57 chevy in that time, a writer said something to the effect of "now they can make them go faster, they need to make them stop faster". One of the reasons is that drum brakes have the "fade effect" which is inherent in the technology, which you can do little about. I am going to go with front CPP "big disk brakes", with drum brakes on the back. My rationale is this: On the road, you are trying to stop a vehicle that is about 3,800 pounds curb weight and all drum brakes in the same amount of time as modern cars, weighing about 1,000+ pounds less, which have at least front disk brakes, if not all 4 disk brakes. Even if you will have a driver show car, you are still on the road with those cars, and stopping distance differences are very real and very different. If you rear end another car, it is still your fault, and you cannot tell the police that you couldn't stop fast enough because you have all drum brakes, LOL... Again, this was my rationale, it is not directed personally at you, it was these thoughts that led to my decision to go disk brakes up front. Bye for now... If you can find statistics on stopping distances given disk brakes v. drum brakes, with various vehicle weights, that would be interesting to see.

 

[mickeywestsr]

power (is great) drums (don't have to have disc), dual mc and proportioning valve, you will be good to go. :anim_25:

Basicly what I run on my 55 ..... :anim_25:
Cowboy :flag6:
:gba:
bowtie-trifive