OLD DODGE'S BRAKES NEED HELP!?

Hello As some of you know I have a 1950 Dodge Coronet with brake problems. In short whenever I drive it about eight miles down the road the brakes lock up. When I check the wheels they are VERY HOT. I am still learning so please be patient with me.

In theory the brake master cylinder isn't releasing enough and the shoes start to rub and generate heat until the brake lines get hot and the fluid can get hot enough to blow brake lines.

It really did burst once right when I bought it on the way home going down a hill the brakes had locked up and I thought I would get it into town before I stopped. That was a BAD IDEA the front driver's side line burst spilling fluid onto the hot wheel and starting it on fire.

SO since then I have been trying to iron out the problem. I replaced all the lines and wheel cylinders and I had the Master cylinder rebuilt (Although it was pretty bad) but they still lock up. Does anyone know what the ploblem might be? and does anyone think that it is the master cylinder?

If so will a 1951 Dodge master cylinder work on a 1950 Dodge? I have heard that it will and the only difference is that the piston inside the 51 is 1 1/16" in diameter versus the 1 1/8" diameter of the 50. Can anyone help me figure this out because I bought a nos master cylinder for a 51 and I hope I didn't just waste my money.

Thanks

 

make sure you have some freeplay at the brake pedal. it sound like the master has the small return hole in the bore covered by the cup. it should be open to release the pressure when you release the brakes.

adjust the push rod at the brake pedal to be a little bit shorter.


jerry

 

Do what Jerry said. But I'm 99.9999999% sure the cylinders are a direct swap. Though I've never heard of the bore difference.

Chris

 

Keep us posted on this,,, I redid my brakes on my 50 Plymouth last summer so if you need help I may be able to offer up some advice. Where are you in Wisc? I am in Menomonie. How was the rebuild bad on your master? Did you do it yourself or did you take it to a shop?

Good luck!

Justin

 

bttt for Jed~

Did you score the NOS master on Epay?
Jerrys got a good point... that was my asumption that the fluid isnt getting back to the master / staying pressurized in the line.

we'll have to look at that before homecoming~
Tuck

 

Even though you have replaced the wheel cylinders, check to make sure that they are releasing when pressure is released from the pedal. I have a friend that has a '50 Hudson and the exact thing was happening to him. He had replaced all the parts with new items so he was really stymied as to what to do next. Another friend*****yzed the problem and proceeded to jack the front of the car up and removed the wheels and brake drums. Then he had someone step on the brake pedal very slowly. He watched the outward movement of the brake shoes. He then had the person release the pressure from the pedal. Of course, the brake shoes should then have returned to their retracted position. But they didn't, as the wheel cylinders had just enough corrossion in them that the pistons became stuck and wouldn't retract! We removed the cylinders, gave them a good cleaning with crocus cloth, reassembled everything and Presto, the brakes worked like a charm. Hope this works for you.

 

yep jed.. the pressure isn't going back to the MC. do you have the split wheel cylinders? half on top half on bottom? probably not, but just thought i would check. say i have some pics of your car on my computer somewhere i will send them your way when i get a chance.

 

Are your brakes adjusted properly? Is your Emergency Brake attached to the wheels or the Drive shaft? If its on the wheels, is it binding?

 

I HAD A 49 PLYMOUTH AND IT HAD SET A LONG TIME AND WHEN I TRIED GETTING IT ON THE ROAD THE FRONT BRAKES KEPT LOCKING UP, THE WHEELS WOULD STILL TURN,BUT THE SHOES WERE DRAGGING CAUSING A LOT OF HEAT.THE PROBLEM TURNED OUT TO BE TWO DIFFERENT THINGS.THE WHEEL CYLINDERS WERE STICKING OUT AND NOT LETTING THE SHOES RETURN TO THE OFF POSITION-CLEAN OR REPLACE THE WHEEL CYLINDERS.THE OTHER PROBLEM WAS THE BRAKE ADJUSTMENT.THESE OLD MOPARS HAVE A LOUSY SET UP,YOU HAVE TO LOOSEN A NUT ON THE BACKSIDE OF THE BACKING PLATE AND ALSO ONE ON THE INSIDE OF THE BRAKE DRUM TO ADJUST THE BRAKES-THIS HAS TO BE DONE ON BOTH SHOES.I THINK IF YOU DO THE WHEEL CYLINDERS AND ADJUST YOUR SHOES RIGHT AND THE DRUMS ARE STILL O.K. THEN YOUR PROBLEMS WILL BE OVER.JUST AN OPINION.

 

Thanks for giving me the great feedback I will try to answer all the questions as best I can.

First I want to say that in my impatience to get the thing driving (and stopping ) and the fact that I couldn't get it towed the whole way to where I live for free through AAA and that I don't have a garage to put it in either (I'm in college I really am that poor). And the fact that I didn't understand the braking systems of cars at all at the time. (I'm a little better off now but just a little )I took it to the closest shop I could and had them work on it.

If I remember correctly I had all the wheel cylinders replaced. I know I had most of them replaced anyway but I will call the shop to find out for sure and which ones (if any) weren't replaced. (they may not know what they're doing but they keep good records)

I took it back to the idiots that work there 3 times after that and I have decided that they don't know what there doing. So now I'm going to fix it in my own backyard.

As far as the master cylinder goes I had that rebuilt by the same guys who did the wheel cylinders because all labor was free cause they didn't fix it the first time. The guy who did the rebuild said that the inside of the master cylinder was pitted pretty badly the 1st time he worked on it. The 2nd time (yes 2nd time) he said he had to bore it out in the back a little more because it was still pitted back there and he thought that might be what was causing the problem. (He said he was afraid to do it the first time because it was so bad it might seal well.

So after that I brought it home (although my dad was actually driving it at this time cause he thought I might be doing something wrong. I don't know how I could magically cause the brakes to lock-up on purpose but he thought I could.

Here's where it gets a little shady. My dad tells me the brakes started to lock-up again then the top of the master cylinder started spewing fluid from around the cap. (I believe him cause I saw the fluid all over the master cylinder)

At that point the brake pedal turned into a sponge, and stopping the car became a challenge.

So I decided that I would buy a new master cylinder and see if that helped just because I was out of ideas besides I was able to score a NOS one off ebay for only 60 bucks.

As far as the parking brake goes the the cable is attached to the driveshaft so I doubt thats the problem.

As far as the brakes being adjusted badly I will check on that when I swap in the new master cylinder.

Whew let me take a breath....

AH... and I live about 30 miles southwest of Menomonie and everyone please feel free to post any suggestions comments or ideas about this situation.

I am glad to know that other people have experienced problems with these type of cars and so that I'm not the only one.

Thanks,
Jed

 

Further to my reply to your problem, even if the master cylinder and wheel cylinders are new you should really check to see if there are any signs of rust or pitting in the bores. Chances are that even if they are new they have been sitting on someone's shelf for quite some time and the chances for rust buildup is great.