1953 Desoto Brakes

I would adjust the brakes just like you would to drive the car, then bleed right rear, left rear, right front, left front. If they do not feel right then you might try the master cylinder.
Good Luck

Paul

Sounds like you've got air in the system. Brake shoes adjustment shouldn't have an effect on bleeding.

To bleed: Fill MC, have able assistant pump brake pedal until pressure builds up then holds it down while you open the bleeder until your assistant tells you the pedal is on the floor. You close the bleeder before she releases the pedal. Repeat until brake fluid runs clear. Start at the farthest wheel from the MC.

When did you do the brake job? Has the problem been there ever since?

Have a nice day
Steve

Thank you. I have been doing eveything in this matter. I suspect the master cylinder. First I will make sure there are no leaks. The front wheel linings and cylinders show no serious problems and there are no leaks there. I will check the rear ones tomorrow. There is rubbing on the toes and/or heels of the linings so I am not sure about these adjustments.

Paul

Mushy as in pump the brakes over-and-over and they are still mushy? Or, pump the brake once twice and firm?? Number 1 is air in there and it could be a bad MC. The second scenario could be the brakes are adjusted too loose.

Also be sure to check the MC push-rod adjustment. If it is too loose, that could be a problem. If it is too tight the brakes would start locking up after several pumps.

Heel toe wear on the shoes indicates they are out of adjustment. Wear should be centered on the middle of the shoe.

Have a nice day
Steve

I am thinking the anchor pins need adjustment. The manual tells me to point them away from the heel of the shoe prior to brake adjustment. So is it OK to have them pointing in another direction when all is said and done? Also, I can not get the desired torque of 55 to 75 ft-lbs due to where the castellated nut with cotter pin ends up. I have been tightening them more but this may not allow the shoe to move around this anchor point. The anchor point has an "oil washer" so this joint must allow the shoe to pivot. I am going back to loosen these up and to put a drop of oiul in them. Jeez, I am really going thru cotter pins. What do you think?

Hi Paul,

Do you have the tools for setting your brake shoes?

The service manual calls for a specific gauge, that swings over your shoes, to set them to the proper diameter, as well as the proper position.

To everyone, who has ever messed with the Mopar brakes, found out the hard way, when they work good, they are great, but, when they out of adjustment, they are terrible.

They are a self-energizing brake. As they start to grab, they pull them selves in tighter, if set right. ( if not , they will lock-up tight)

The little MoPar service book on brakes, explains this to a "T".

If you use the larger, brown cover service manual, that you have, and follow it, stet ny step, you have nothing to fear.

I believe (guess), that since you have never messed with your brake shoe settings, it must be your M.C.

I made a set of tools for the brake job, if you need them. I have loaned them out to many members through out the years.

Mark

Mark, I have been changing the adjustments on the brake linings all along. I have (I believe) your drum and lining tool that sweeps over the linings. When the linings were brand new, I remember that I could not get the shoes perfectly in place but thought it was acceptable. Now I am wondering. I will put the tool on them again.
There is no leakage at the master cyl (checked it yesterday) so I would think it is OK. The linings are not showing wear except at the top quarter and bottom quarter of the lining length - so there is some adjustment problem or lining problem. Has anyone had problems with new relined linings?

Hi Paul-Haven't talked with you since Albuquerque. If your linings are contacting the drums only at the heel and toe then the linings have too small a radius for the drums. This might be because the drums are badly worn and move than .060 over standard 12.00" size or it might be because the linings are incorrect for the car. I had one set of linings which had to large a radius for the 55 or 56 Desoto-could not install the F. brake drums after mounting the shoes.
Suggest pulling a front drum and taking to a brake shop to measure size with a brake drum gage. Should not be more than .060 over standard 12" size. While you have the drum off measure using a tape measure or even better a caliper the distance from the heel and toe and the center part of the linings to the center or edge of your axle spindle. An original Chrysler tool is best but you can use a caliper and measure to the edge axle spindle from these 3 spots. This distance should be little less than half the diameter of the brake drum as measured with a drum gage.
Remember Chrysler dealers had a grinder which slid over the tapered axle and ground 360 degrees on both linings to get a perfect radius to match the drums-we don't have so the linings must have a radius closely matching the drum and then must be worn in by driving.
One end of each lining is firmly bolted to the eccentric pin and brake backing plate and will not "float". The other end can move closer to or away from the drum as actuated by the wheel cylinder.
Having said this, I suspect your mushy feeling is tied to problems with the master cylinder or air in the brake fluid due to improper bleeding.
Ford and GM linings do float somewhat loosely on the brake backing plates and adjustment isn't so critical -not so with the Chrysler system because one end of the shoe if firmly bolted to the brake backing plate by an eccentric bolt.
On my 55 Desoto-same system as your car-I had problems with the brakes after years of good operation and had to replace 2 of the 4 F wheel cylinders because they had worn prematurely. These 2 had a different poorer design than the other 2 so don't rule out wheel cylinders. Based on my experience with a 54 Desoto, the shop manual has a good logical explanation for adjusting the shoes but it is hard to understand. Your situation is complicated by the difficult access for the chassis mounted master.
Martin Lum

It was nice to hear from you again Martin. You are always helpful. I will try all of your tips. I do have a question on the anchor pin. Doesn't the lining have to pivot about the pin to allow the shoe to move outward when pushed out by the wheel cylinder. I have those pins tighter than the recommended torque to install the cotter pin through the castellated nut. I was thinking of loosening those and putting in a drop of oil since there is an "oil washer". I figure the oil washer lubes the pivot point. Are you going to make it to Reno?

I have been working on the brakes on a 35 Dodge this week, and ordered new linings from a source in Mass. I could not get a solid pedal no matter how I adjusted the shoes. I took the new (China made) shoes off and compared them with the original shoes and the new ones are 3/8 inch smaller. I reinstalled the old shoes after thoroughly cleaning them and had a solid pedal that will lock up all wheels with normal pedal pressure. I called the place I purchased the new shoes from and they said I needed an expert to install the faulty shoes, the shoes are on their way back now for a refund. I have done brake work on over 100 Chrysler built vehicles in the past 25 years and this was a first for me.

When I was a kid we re-lined shoes and then arced them to fit the drum. This is the way to get perfect brakes. We had a Bear brake machine that cut the drums on the lathe and arced the shoes to fit at the same time so the shoes fit each drum perfectly.

When we re-lined those shoes we would use 1/4 inch lining, then arc them. If you don't arc them, you won't be able to get 1/4 lining to fit inside the drums. You need to use a thinner lining like 3/16 if you can't find a place to arc your shoes.

Or.....a heck of a lot of sandpaper!

Have a nice day
Steve

The shoes must pivot freely on the anchor pin. It doesn't matter much if it is slightly over-tightened to line up the cotter pin; the torque on the nut shouldn't affect it. Remember that the anchor pin adjustment is critical to the brake adjustment so you need to be certain the anchor pin does not rotate as you tighten the nut.

Have a nice day
Steve

Steve, please check my may 22nd post concerning the anchor pin.

"I am thinking the anchor pins need adjustment. The manual tells me to point them away from the heel of the shoe prior to brake adjustment. So is it OK to have them pointing in another direction when all is said and done? Also, I can not get the desired torque of 55 to 75 ft-lbs due to where the castellated nut with cotter pin ends up. I have been tightening them more but this may not allow the shoe to move around this anchor point. The anchor point has an "oil washer" so this joint must allow the shoe to pivot. I am going back to loosen these up and to put a drop of oiul in them. Jeez, I am really going thru cotter pins. What do you think?"

Thank you all. I believe I got the front ones adjusted and will check the back ones tomorrow. Thank you Mark - I used the brake adjusting tool successfully. In the past I did not have anything to place into the back side of the front drum where the shaft seal resides. I needed a shaft or cylinder to center the tool as I swept the inside of the drum. I found something that fit both the seal and the tool perfectly today.
I am greasing everything up now while I have the front wheels off.