1953 Dodge B4B 1/2 Ton Brake Drum Max Diameter

[Dan693]

Brake Drum Max Diameter

My 1953 Dodge B4B 1/2 ton has 10" drum on the front and 11" on the rear.  What is the maximum diameter they can be turned?

Thanks Dan

[JBNeal]

That info should be in the highly useful factory shop manual, I found a reproduction from Faxon that was quite reasonable...fits in nicely on the bookshelf with the other shop manuals

[Robert Harrison]

As far as I know the factory never provided over size specs for brake drum turning in this period.  I just looked through all the stuff I had to make sure I did not have anything.  This wigs out the people like Les Schwab because they don't want to touch an Item where there is no dimensional trail due to corporate wimpy-ness.  

My father-in-law took his 1960 half ton into get an oil change to one of these corporate oil change outfits and they said they couldn't change the oil as it was not in their computer. 

A general thumb max oversize is .12  so between .080 and .12  You may have to take it to a machine shop or a small shop who is less ridged  Nobody makes the drums anymore that are riveted to the hubs.  

That dimension may be a little conservative but was provided to me from a reliable source.  Considering that most of your stopping power is in the front of the truck and the big 11 inch brakes are in the back I would be  comfortable on my own truck going beyond that on the back especially if you are the driver and you don't really carry any loads.  These trucks in the days usually traveled about 35 miles an hour maybe 45 or 50.  Basically if you were to over size and noticed brake fade you have likely gone too far.

Les Schwab will size your drums for you though.  And I would consider marking each one as he does so as to not confuse them.

I have considered replacing the drums by grinding out the rivets on the hubs and using later drums and just bolting them on like modern drums but you would have to make sure the hub diameter, bolt pattern, drum dia and width are the same.  Maybe a later Dodge D100 drum?  I would imagine if you were to come up with a substitute drum you would also have to match it to the hub by having it turned on that hub.

These guys will take your drum shipment, turn the drums and provide new arched linings for a perfect fit but don't count on them to cut the drums more than .120

Brake drum over size.  If you do ship your drums be sure and have them sized before you should ship them.

 

Brake and Clutch supply (formally Friction services)

Seattle 206 622 5655

 

Oversize turning of drums

 

.120 usually between .080 and .120 

Bob Harrison

 

[Dan693]

JBNeal:  I do have an original Mopar shop manual.  I took it along with the engine to the machine shop last week so they would have access to all of the engine specs.  They are 2 1/2 hours away one way so not easy to reference it at this time. 

 

Robert:  Thank you for the great reply.  My drums are in pretty good condition so they only need a light cut to make sure they are round.  I am looking for the max diameter to make sure they have not already been turned a few times.  It is my believe that they have not been since the odometer reading of 49K looks to be authentic based on the condition of the engine bore and bearings.  It would have only needed honed with new std. rings and bearings if one on the cylinder walls had not been scratched.  The truck lived it first live on a farm here in Ohio.

[Los_Control]

If it were me, I would only cut them as a last resort ..... not because it is a good idea and how it was always done.

 

To replace the drums is very expensive, I only know one supplier charging $400 each ..... To me I feel better off doing a rear end swap with better gears, brakes, E-brake, u-joints for a cheaper price.

 

Depends what you want though .....If going for total restore you want original.

 

I can share a 1960 Dodge 1/2 ton truck can be used right up til they cant.

Mine wore so thin that the drum actually split in 1/2 .... The one drum came off in two rings ..... still had brakes to drive it home & replace it.

23 minutes ago, Dan693 said:

My drums are in pretty good condition so they only need a light cut to make sure they are round.  I am looking for the max diameter to make sure they have not already been turned a few times.

 

As others have said, at this day and age there was many things that nobody cared about and was not documented.

I would just be more concerned with how much meat was left on the drum and how safe it would be to use .....

 

I bet many modern replacement drums come to a certain spec, not even able to turn them once .... just throw away and replace.

[JBNeal]

additional information - B-series brake drum replacement (11")

[Dodgeb4ya]

MoPar started posting maximum drum oversize's around 1956...

I know most drums machining limit is at .060" OS. A maximum safe cut on the drum lathe bit is at .030" ....means the drum ends up at .060".

But I also know some  late 50's model Chrysler 12" drums are spec'd at a max drum oversize of .090".

Shown is a MoPar pic of some center plane brakes maxed at .060" oversize cut.

Anything over .060" will require over size linings for proper shoe arc'ing and long lining life.

More meat on the drums is a good thing.?