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1949-52 Plymouth: Are 11" Dodge Desoto drums compatible?


1951plymouth
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Hi all,

It's time for a major brake service on my stock 1951 Plymouth.

I have read lots of forum posts discussing that the stock brakes operate well if properly adjusted for most below 65 mph or so and that the various popular front disc brake conversions improve braking/safety, especially with a dual master cylinder conversion.

In doing my research on this and other forums I see that dodge/desoto had larger 11" drums and Chrysler may have had 12" drums. I have no experience with the dodge,desoto and chrysler.

Question: Do these 11" and/or 12" drums/backing plates etc interchange with 10" Plymouth drums? If so, wouldn't the greater braking surfaces be "better", i.e. less heat,fading and shorter stopping distances? Is this a viable potential upgrade for Plymouths?

Thank you for any helpful info. Mike

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for the work involved...unless your 10 inch drums are shot to hang, the time and trouble involved would not really be worth the little if any change in effective braking...however, the call is yours...the braking surface in the shoes is approximately 2 inches greater per wheel..

 

just read again what I wrote...that is 2 inches added length per shoe per wheel...an increase for sure but let me point out that even with the added material, if you do not adjust them with the proper tools odds are you are not making full contact regardless of what size drum you running...

Edited by Plymouthy Adams
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Regardless of what else you do,installing  a dual-outlet master cylinder is the wise move to make.

 

As for your stock brakes,they are perfectly adequate for normal driving. The reasons the larger cars had larger brakes is BECAUSE they were larger cars that were heavier,and needed larger brakes.

 

As for swapping to disc brakes up front,if your drums are too worn to be turned,it might be cheaper these days to just change over to disc brakes up front than it would be to track down and buy NOS drums,new shoes,and new wheel cylinders.

There can be no question that disc brakes stop better than drum brakes. Or that drum brakes are adequate for stopping at speeds and loads normal for the car when new.

 

On the other hand,IMHO,if you have modified the car with a later driveline and cruise along down the intestate at 75 mph or so on a regular basis,you are nuts if you don't swap to discs up front and a dual outlet master cylinder.

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Does anyone repro Plymouth brake drums?  Cast iron should be easy to cast.  They were the same for years and millions of cars were sold, so there's probably enough of a market to justify manufacture.

I am pretty sure you can buy new ones,but they were cast in China. I can't speak for you,but I am not about to trust my life and my car to brake drums made in China.

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I put eleven inchers on my 50 years ago and the brake fade problem went away.  You will need the backing plates for all 4 corners and the spindles from the front.  It is also necessary to reset the toe in after changing the front spindles as the steering arms are 1/2 inch lower than before.

If you are considering US Dodge drums then you will notice the offset is different.  Desoto and Canadian big Dodge have the same offset as Plymouth

 Plymouth wheels will fit both.    however, Plymouth wheels will not fit the 12 inch drums found on Chrysler.

 

At the time I did this, (1968 ) this made a difference in braking and I got 50 000 miles out of the linings.   Cylinders and hoses are the same.

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  • 2 months later...
On 8/4/2016 at 5:31 PM, dpollo said:

I put eleven inchers on my 50 years ago and the brake fade problem went away.  You will need the backing plates for all 4 corners and the spindles from the front.  It is also necessary to reset the toe in after changing the front spindles as the steering arms are 1/2 inch lower than before.

If you are considering US Dodge drums then you will notice the offset is different.  Desoto and Canadian big Dodge have the same offset as Plymouth

 Plymouth wheels will fit both.    however, Plymouth wheels will not fit the 12 inch drums found on Chrysler.

 

At the time I did this, (1968 ) this made a difference in braking and I got 50 000 miles out of the linings.   Cylinders and hoses are the same.

Hi Dpollo and all others,  thank you so much for the replies on my thought of converting to 11" brakes from 10" as an improvement to brake fade.  It was just an idea I had to postpone the expense of converting to disc brakes using factory parts.    I will be disassembling and inspecting brake system this week to determine my needs.  I have been hobbying w my 51 Plym for 5 or so years, done massive research, and ultimately purchased the Ammco brake gauge for this brake job so I hope stock brake operation is signif better than before my first rookie brake job.  I will update after I do teardown, though I suspect my previously installed nos ALUMINUM wheel cylinder pistons are worn, along w rubber parts causing fluid leaks which also ruined brake linings.    I plan to have linings matched to drums as I found an old school shop to do this and plan to mark linings w permanent marker so I can determine the extent shoe lining contact w drum after major brake adjustment.   Either way I think I will also continue to evaluate and look for the Canadian backing plates, spindles and brake parts for possible conversion.....I like this idea and own the brake gauge so it seems like a viable course of action.  Thank you for your thoughts on this parts swapping and compatibility!  I'll be back!

Ps...Sorry for delay.  While I have read many many many posts (or threads?),  I have not posted much and am still trying to figure out how to work this website!   I didn't get any notifications that there were responses so I didn't know to respond.  I hope to be more interactive when I get the hang of it. Thx.

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On 8/4/2016 at 8:17 PM, Plymouthy Adams said:

don't buy a late model car is my only advice...

Well,the cast iron and other materials in modern cars is a lot safer because it was cast/manufactured to US standards under contract. The generic replacement parts you buy at parts stores were made to the alleged standards of whatever Politburo relative that happens to be running the company for his real boss. Which means there is virtually no quality control whatsoever. It may be good,but chances are it is junk.

Still,I don't take any chances. When I had to replace a front hub on my 06 GMC 4x4 diesel hauling truck last year,I bought a genuine GMC hub from a dealership.  Yeah,it cost me over twice as much,but it's not going to fall apart in less than a year,either. Given what shops charge for labor anymore,it is false economizing to buy a junk part that won't last a year when you can buy a quality part for twice as much that will last for years.

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2 hours ago, 1951plymouth said:

 

Ps...Sorry for delay.  While I have read many many many posts (or threads?),  I have not posted much and am still trying to figure out how to work this website!   I didn't get any notifications that there were responses so I didn't know to respond.  I hope to be more interactive when I get the hang of it. Thx.

Look up towards the right top part of each page,and you will see a black box that says "Follow:. Click on that box and you will be notified anytime anyone makes a new post to the topic.

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