1936 Dodge Brakes

dodge
brakes
charger

#1

I don’t have a Charger, my question is regarding a 1936 Dodge sedan, CarTalk doesn’t have a catagory for it. I have been trying to get the brakes to work but am running into a problem… All the wheel cyclinders have been rebuilt as well as the master cyclinder. I tried to bleed the brakes, I removed all the air from the lines by bleeding but the brake peddle is still soft and the brake shoes aren’t moving. I have no leaks in the system. At first I thought the peddle wasn’t pushing the master cyclinder far enough in. I removed the master cyclinder and measured the movement of the rod pushing the cyclinder, its 5/8", is that enough? Also, when I was bleeding the brakes I had my wife pumping the peddle for me, she just told me that she wasn’t pumping all the way to the floor. Could that have been a factor (I know but she was the only person available)? Any thoughts.


#2

Your wife shouldn’t pump the brakes. She should put steady pressue on the brake petal. When you open the bleeder valve she should feel the brake petal go down. You need to close the bleeder valve before she lets her foot off the petal and then check the master cylinder to see if you need more fluid.

Perhaps you should go to the auto parts store and buy a brake bleeder kit so you can do the job solo. This is going to take a while to get all the air out of all the brake lines.


#3

The brake rod should move closer to 3", not 5/8". Is the pedal return spring missing? Where is the master cylinder? On the firewall or under the floor-boards?? How many wheel cylinders in each brake, one or two?? Did you bench-bleed the master before you installed it??


#4

Thanks. I think your right about going to the store and buying the bleeder kit. Thanks again.


#5

The master cylinder is under the floor board. The peddle return spring is on. Each wheel has 1 cylinder. And I DID NOT bench bleed the master before I installed it. Actually I never heard of bench bleeding. Can you give me some info on that. Thanks


#6

I am also wondering why I only have 5/8" movement. All parts that were replaced are identical to old parts. Even if I adjust the peddle rod out to its longest length its only about 1" of stroke. If I extended the peddle rod by welding an extention would I cause any problems?


#7

After 74 years I’d say you’ve got to do the whole system . . . and since you’ve mentioned almost everything . . . what about the brake lines? Crimped? Rusted? Bent? Corroded? You can have all the pressure in the world from the rebuilt master and great fluid from the wheel cylinders . . . still have to get fluid pressure through the lines. Just my two cents. Rocketman


#8

Lines are all new and I do get fluid out of them when I bleed them.


#9

I would find an old car/old Dodge forum, and strike up a conversation with an owner. I would not start welding things, it’s more likely that something needs to be corrected or you have a wrong part.


#10

If she was pumping while you bled the brakes and you did all four, then you have air throughout the system. Probably lots of it.

The MC should have been bench bled. I’ve attached a link with instructions.
http://www.misterfixit.com/brakbld1.htm

The best technique I know of to bleed the system is to put a clear plastic tube from the bleeder into a clear plastic bottle hung next to the bleeder and 1/2 full of fresh brake fuid. That way, when the pedal is pushed in the air in the tube and in the system “burps” out the fluid in the bottle and any backdraw pulls fresh fluid back in without air. You should start with the cylinder farthest from the MC.

Sincere best.


#11

M.B.'s advise is good…Too late now…Brake pedal travel might improve as air is removed from the system and the brake shoe return springs push the master cylinder piston back where it belongs…Don’t extend the brake rod!!

Step one: Have someone pump the brake pedal several times and then hold it down as far as it will go. Open the brake line fitting at the MASTER CYLINDER at let any air escape WHILE THE PEDAL IS BEING HELD DOWN! Close the fitting and release the pedal. Repeat until nothing but fluid squirts out. THEN go to the R.R. brake and do the same thing using the bleeders. Then L/R, then R/F then L/F. Remember, when you have a bleeder open, the brake pedal must be held down…When you close the bleeder, yell, “OK, pump it” and repeat. Be sure to check the fluid level in the Master after every two or three “bleeds” so you don’t run it dry and pump air into the system again…As air is removed, the pedal “feel” will improve…


#12

Thanks. The link is very informative.


#13

Regarding the rod travel-did these brakes work before you began your rebuild? At any time in the recent past? If so, then either the air’s causing a problem, a new part isn’t right, or something not attached correctly.


#14

One of the brakes were actually locked up when I got the car (left rear), took almost 2 hours to get the drum off. The new master cylinder is identical (all measurements-inside and out) to the old one (which was original) and the push rod is original and mounted to the peddle assembly which can only go in the same spot, so I am pretty sure its not a parts issue.


#15

Sure sounds like air in the system. I don’t know if gravity bleeding will work on a really old braking system, but I can’t think why it wouldn’t. It’s dead easy to do. All you do is crack the bleeder on one wheel. And wait for a great many minutes – half an hour, maybe longer – while brake fluid and hopefully the air in the line and wheel cylinder trickles out. Check the level in the master cylinder occasionally and keep it full. Tighten the bleeder and move on to the next wheel. If you are lucky, when you have done all four wheels, the brakes will work.


#16

I thought about the gravity bleed too, and it might be worth a try, but on this car the master is mounted below the floor-boards and is almost level with the wheel cylinders, so gravity has little to work with…


#17

Yes, you are correct, some of the lines are even higher then the master cylinder.


#18

You may have to resort to getting on of those little “miti-max” vacuum pumps to pull the air bubbles out of the system. If you have lines that run higher than the master cylinder, you could have an air bubble that goes so far when the pedal is pressed down, then travels back up the line while you are closing the bleed valve and getting ready for the next pump.

The vacuum pumps work pretty good, except that they suck air in around the threads of the bleeder valve while it is open, so it won’t be a final step in the bleeding process, but it will pull the persistent air bubbles out of the brake lines. You can put some grease around the threads of the bleed valve, that helps some.

As for the piston travel for the master cylinder, I don’t think its anywhere near three inches. I would expect less than one inch of travel.

I think there used to be a pressure bleeder adapter for these old systems. You would have to find an old (very old) mechanics shop that might still have one. It adapted to the master cylinder, You would fill it part way up with brake fluid, closed it up and pumped air into it with a bicycle pump. Then you opened each wheel cylinder, starting with the furthest, until the bubbles stopped. I wonder if JC Whitney still has them?

One more thing, I don’t remember ever having to bench bleed a single master cylinder, I think that started with the dual master cylinders.


#19

Very useful info. I found one of those bleeders at Eastwood Co.
http://www.eastwood.com/early-american-auto-power-bleeder.html

Thanks.


#20

Well, I got the pressure bleeding system and bled the brakes again and still the same problem. no resistance on the peddle. I took all the wheel cylinders off and checked them. I found a small leak in the front right, cleaned it up and put new cups in. I removed the master cylinder and rebuilt it with a kit I was saving to use at another time. Put everything back together and hooked up the pressure bleeder and put 8 pounds on the system and let it sit for awhile and it held the 8 pounds. I bled the brake and STILL the same. I’m almost ready to give up. What about the springs on the brake shoes, could they be too tight? They are the only things in the braking system that aren’t original. Or what about the brake fluid, I am using DOT 3 type fluid. My dodge repair manual says to use a ISO Brake fluid but I can’t find out what that is. Also, I usually work in the garage with the door open and during the day the temp is usually between 32 and 40 degrees. could the temp have something to do with my problem?