Brake shoes with primary and secondary linings

[JerseyHarold]

Back in engineering school, I was taught that internal expanding brakes are self-energizing on one side.  This means that the spinning motion of the drum pulls the brake shoe harder against it thus increasing the braking force.  The brake shoe pivots are arranged so that both front brake shoes are self-energizing.  That's why the front brakes in our cars have two 'half' wheel cylinders.    On the rear brakes, only one shoe is self-energizing, again because of the pivot locations  As I recall, the the rear shoe on the driver's side rear wheel and the front shoe on the passenger's side rear wheel are not self-energizing so they have smaller linings.   It's been a while since I learned this stuff, so if anyone wants to make corrections please feel free to jump in.

[mopar_earl]

I checked my manual out and found no mention of the rear shoes and how they go other than one pic that shows the short lining shoe faces rear. 

 

 

Earl

[Plymouthy Adams]

mopar_earl, on 10 Nov 2015 - 08:49 AM, said:

I checked my manual out and found no mention of the rear shoes and how they go other than one pic that shows the short lining shoe faces rear. rps20151110_084725.jpg

 

 

Earl

if that picture does not scream it out loud enough for you..nothing anyone here can say will get through either....lol

[50net]

i pulled my rear drum off my 1950 coronet and someone put long lining towards front of car and short at rear.however looking to order new shoes all companies state same shoes for front and rear brakes 11x2 ???

[Dodgeb4ya]

Same shoe lining length primary and secondary for your dodge. That's all you will get today unless you get a custom shoe reline job.

[desoto1939]

Same shoe lining length primary and secondary for your dodge. That's all you will get today unless you get a custom shoe reline job.

that is if you are buy froma vender but if you are buying the old style rivet lining and are getting the correct number you can still get the long and shoe lining.  I always buy th eold lining with the rivets and reline my old metal shoes.

 

Rich Hartung

[Niel Hoback]

So, I would think that if you get bonded relined shoes you could shorten one of each side to the length of the NOS shoes. A hacksaw would do the job nicely.

[Dodgeb4ya]

The factory correct bonded shoe lining length you want to go with on your D-42 dodge is.....

 

Front brakes.....11.5" lining length on both primary and secondary shoes.

Rear brakes......11.5" lining lenght on forward primary shoe...8.8" on the rear secondary shoes.

Bob

[50net]

How will it affect rear brakes if you install the shoes being made today? Full 11in

[50net]

Looking in my dodge shop manual both shoes look to be same length for rear

[50net]

[Dodgeb4ya]

I too looked in all the MoPar/Dodge shop and parts books looking for differences in 1951-53 shoe lining lengths... could not find any specs..lining length looked the same front and rear in the factory 1949-52 dodge car shop manual.

 

I found the different 1951-53 dodge lining lengths in one of my 10" thick professional "National Data" books.

 

I don't think it really would make a lot of difference in braking operation today as brake lining materials are different today than when MoPar supplied them.

 

Many cars did/do have short primary front lining length and longer secondary rear lining length opposite of our old MoPar cars.

 

 

[50net]

I guess bottom line is we get what we can get today just as long as brakes STOP dont think anyones going to be looking under drums

[50net]

If duesenburg would have submitted a patent for his hydraulic brakes we wouldnt be calling them lockheed today

[50net]

Still trying to get last drum off.drum turns free.tried heat,rustbuster i have puller on so tight it made a U in crow bar.any suggestions???what would break first puller or drum freeing?

[casper50]

5 pound sledge hammer.  Make sure to have the axle nut screwed on some.

Edited December 1, 2015 by casper50

[mopar_earl]

I leave the nut on a couple threads, use a correct puller and use an impact to drive it. Stopping occasionally to hit the puller bolt with a hammer. The puller must be sqaure to pull correctly.

Once apart use Scotch brite and/or emery cloth to clean up the shaft, drum bore and key and keyway. I than antiseize the heck out of it. Don't antiseize the threads, leave those clean and dry or you will over torque it. Next time you pull them, they will come off much easier.

Earl

[mopar_earl]

Oh and lube the puller bolt threads with bearing grease.

Earl

[Plymouthy Adams]

DO NOT HIT the puller bolt end with a hammer..the shock is felt through the axle on to the thrust block and out to the other axle and on to the retaining plate opposite side....you can do some serious damage....read the manual if you are in question...this is an IMPORTANT caution in the book as it is in bold text and enclose in an outlined box...safety for the car...safety for you..

[mopar_earl]

I didn't say hit it full force with a 30 lb hammer. Sometimes common sense needs to be applied lol

Earl

[mopar_earl]

Hitting the puller bolt with a 20 oz hammer or so wouldn't cause any force greater than the axles see under load driving and making turns.

Earl

[50net]

Have nut on snap on puller on correctly and greased using 4-6ft pipe to turn.dont think can turn any more without something breaking?used mapp gas.soaked with rustbuster drum turns so not shoes.if i get oxy/acet set ,how hot to get near spindle on drum ?dont want to crack it .drum is under alot of pressure crow bar twisted to a u!

[50net]

When looked at other drum looks more likely to be fused at rear of drum to spindle

[50net]

Unfortunately i have a dodge repair manual reprint from the day.it was for the mechanics does not get into details

[mopar_earl]

Unfortunately i have a dodge repair manual reprint from the day.it was for the mechanics does not get into details

Yes the Dodge manual sucks badly. Hardly any details at all. Sounds like the Plymouth maunals have more info in them. I've Thought about buying a Plymouth manual.

Earl