National Desoto Club

This is not new to me but I've never seen or read anything regarding the front drum brakes locking up when the pedal is depressed and there is rain or high humidity and the car has been sitting for awhile. Seems like the shoes absorb moisture and become very "grabby". The more the car is driven, the lesser the problem as I believe the moisture in the shoes evaporates with heat. This issue existed with my former '60 Chrysler and now with my '59 DeSoto.

Anyone else have this experience? If so, did you find a solution?

Please advise.

Thanks!

Hello,

Be sure they are adjusted correctly. Keep in mind they are self-energized.
If properly set-up, they will tend to apply more pressure, without more pedal pressure.

I am the tech adviser for '52, but the brake set up is the same for a lot of MoPar years. My Dad had a '59 with VERY touchy front brakes. We ended up getting new shoes, and had the shoes machined to match the drum diameter. It solved the problem. Looking back, I think the shoes were exposed to brake fluid at one time, due to a leaky wheel cylinder.
I have seen other Mopar's, with the brakes adjusted so bad, that the wheel even locks up, and to get it to release, you have to back up.

I have the small Mopar Tech book, that really goes into detail, how they work.

Made myself a set of tools to set the brake shoes, and it works wonderful.


Mark Waite

Thanks Mark, I did adjust all the brakes per the repair manual instructions and they work perfectly fine until the car is subjected to moisture and sitting still for any length of time. The self energizing feature is functioning as well and the brakes release immediately even after lock-up once the car is stopped and put in neutral. They hold in lock-up as long as there are forces on them such as the car being in DRIVE when the brakes are applied and not released by putting the car in neutral, if you know what I am referring to.

I've had the wheels/drums off and can see no indication of brake fluid or wheel cylinder leaks - in fact the previous owner had them all replaced and gave me the receipt for the work done as well as a new set of wheel cylinder rebuild kits he had. The linings are new too.

I'm stumped! My only thought without knowing any specific reason or any other corrective action, is to just put new linings on and see if that makes a difference.

Because the drums are cast iron, and porous, brake fluid COULD still be in them. Find a really good de-greaser and wipe them many times. That is cheaper than all new brake shoes.

One other thing to check....................pull off a shoe, and physically put it in the drum, and see if it makes contact all the way.

If the drums were ever turned, the radii may not match. Also check to see if the shoes are square to the drum.

I went through all this with my Dad's '59. Ended up the shoes we not the the correct radii + not square with the drum.

It was a real hair pulling event, because we could never figure out, what was really wrong. .....................Then I read the silly little Mopar Tech book. All of these tips were in it.


Mark

Thanks Mark - will do. Probably a nice little winter project.

"It's delightful, it's delovely, it's DeSoto"

Fred...are the '59 brakes still considered the "Center Plane" brake design?

Mark

Mark K.

I'm not sure about "Center Plane". I've heard the term but am not familiar.

What do I need to know or look for?

Thanks,

Fred

I've got a Raybestos publication from back in the day geared toward servicing the Center Plane brakes. It is written for the independent shop, not from the factory perspective. Thought it might help. I'll try uploading it later today when home.

Mark

Here is the Raybestos guide to servicing the Center Plane brake. Maybe this will be of some help.

Mark

Thanks again Mark,

I can't recall that mine look any different than those pictured. I can say with certainty that my adjusting procedure is identical with what is shown so my guess is that they are center plane brakes.

I'll just wait till winter and tear into them.

"It's delightful, it's delovely, it's DeSoto"

Hey, Fred-

I had the same issue with the front brakes on my '59 Firesweep. Roughing up the brake pads with sandpaper was temporary relief, but they must have been contaminated at some point. Having new pads intalled on the shoes cured the problem.

Good luck.

Glenn Colburn

Glenn,

Thanks for your input. I am curious as to what type of contamination you had experienced if anything other than moisture. Because mine work perfectly fine once the brakes are used a few times or if I am at speed where the dynamic inertia is great enough that it overrides stickiness which builds up heat and evaporates moisture. It's got me stumped..........

When you put new linings on your shoes and the problem went away, perhaps it indicated the moisture affected whatever contaminants were in the old lining more so than the lining material???? Good possibility based on your finding. I'll be prepared to replace the linings when I tear into it this winter just as a precaution. But I'd sure like to know the real cause so I can eliminate the "band-aid" approach.

"It's delightful, it's delovely, it's DeSoto"

I have a 39 Desoto that had the bonded lining on the brake shoes instead of the riveted lining. The bonded lining for some odd reason started to glse and then the car was pulling to one side. I would pull the drums to see if any contaimination or brake fluid and they were dry and clean both the shoes and the drums. I would sue sandpaper on the lining and this would help for a while. Spoke to a mechanic and they have been finding that the newer bonded lining are getting hard surfaces and then sometime s they will grab and pull.

I have the Ammco brake tool to adjust the brakes and now have gone back to riveted lining and th eissue has gone away.

Rich Hartung
Desoto1939@aol.com