1956 Brake Drum Condition

[knuckle47]

I have removed the drums today on this ‘56. I see that all of them are in this condition. I hate to ask but: do these need to be replaced? This broken edge continues in random places around the drum’s circumference

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[cokefirst]

If the drum is still within spec size wise you should be OK.

 

[jimntempe]

That was supposed to be the lip that went around the lip on the backing plate to keep water and dirt out. If the drum is otherwise OK the only problem I would see is that with it missing random chunks it may be a little out of balance compared to one without the missing chunks. I'd probably use it and see how it drives once you have it back together, new tires on and can see how it feels and handles.

 

[knuckle47]

I will measure the drum thickness and go from there. Thanks for all of the input.

 

[Ward 57]

That was supposed to be the lip that went around the lip on the backing plate to keep water and dirt out. If the drum is otherwise OK the only problem I would see is that with it missing random chunks it may be a little out of balance compared to one without the missing chunks. I'd probably use it and see how it drives once you have it back together, new tires on and can see how it feels and handles.

I think there are still places that can balance tires on the car. Just make sure you mark the tire to the drum. I was also wondering if that condition is on all the drums, I would suspect someone at some time whacked them there to get them to come off. Probably not knowing that was the weakest part of the drum but thinking the outer edge will cause a little twisting up on the other side. Lord knows we've all seen, shall I say experiments that went wrong.

 

[Frankie the Fink]

[rant] That broken part around the rim is usually due to some Bubba that can't get the drum off due to seized or over adjusted brakes beating on the rim to get it loose. I'm gonna be the naysayer here; the drum brakes on my 63 Corvette saved my life because I kept them 100% up to snuff, nothing marginal was allowed to remain on the car damaged components were replaced and they were regularly maintained. The damage and corrosion you show affect rotational balance and heat dissipation.. As mentioned that lip also keesp contaniments and moisture out of the working parts of the brake system.

It doesn't matter if the car is lightly driven, my crash was on a bright Sunday day in rural Florida on a straight road heading to a veteran's car show when some uninsured clown pulled right across in front of my in an Escalade. My drum brakes hauled me down from 40 mph to a survivable velocity in nanoseconds and I still did the "steering wheel taste test" and was knocked out.

My heartfelt advice is to get new replacement drums for that car - on all four corners; the front drums aren't too expensive the rear drums (for some reason) are double the price of the front. I wouldn't care -- I don't cheap out on brakes - PERIOD.
If you are determined to "cheap out" at least replace the front drums; they do 70% of the work when braking. [/rant]

 

[knuckle47]

@Frankie the Fink ….is this the same corvette you had posted last week? Was this before or after that photo?

Your comment is lucid and well stated and I truly appreciate and take to heart. Actually, that is the biggest reason I have become so deeply involved in gutting the garbage on this car. She’s a very pretty red and white car but there are elements like steering linkages, suspension parts and brakes that just don’t strike me as “solid?” I was an educator in motorcycle rider safety as a fun weekend distraction when I was younger( took over my life as a program administrator). You can only imagine the images that I have seen from bad equipment and mediocre riding skills. To ME, accident avoidance is my goal with all that I get involved with and your rant hit a nerve.

I bought 4 new drums today, new brake lines and fittings, bearings, master cylinder re-build kit, and a gallon of DOT 3.
My new rear springs showed up this afternoon so between the springs and the brakes…..I ain’t driving it for a while
I thank you for taking the time to write your “rant”. Something that should be first in mind.

 

[Frankie the Fink]

The Corvette picture was post-accident., it was repaired to stunning perfection after the wreck by an expert with 50 years in the business. and becane a better car in many ways for the effort..so no worries... As an aside I hgihly recommend National Corvette Museum classic car insurance - they issued checks totalling about $66,000 to repair the Corvette with no questions asked. They insure ALL classics and limited production cars including my 2002 Thunderbird.

 

[rponfick]

The Corvette picture was post-accident., it was repaired to stunning perfection after the wreck by an expert with 50 years in the business. and becane a better car in many ways for the effort..so no worries... As an aside I hgihly recommend National Corvette Museum classic car insurance - they issued checks totalling about $66,000 to repair the Corvette with no questions asked. They insure ALL classics and limited production cars including my 2002 Thunderbird.

I second Frankie's recommendation on the NCM insurance. I have had them cover a variety of cars, including multiple Corvettes. Just be sure the restrictions are acceptable to you. I exceeded their 6000-mile yearly limit after driving my 2020 home from Museum delivery, and had to move it to my daily driver car coverage for a year.
Frankie, I think I remember you as a frequent commenter on the Corvette Forum.
Ralph

 

[Frankie the Fink]

Then NCM mileage limitations "carry over"; if you have a 6,000 mile limit and only use 4,000 then next year you have 8,000 available - a feature often overlooked and not well documented. And yes, I was on the Corvette Forum frequently but not recently (long story).

 

[rponfick]

Then NCM mileage limitations "carry over"; if you have a 6,000 mile limit and only use 4,000 then next year you have 8,000 available - a feature often overlooked and not well documented. And yes, I was on the Corvette Forum frequently but not recently (long story).

I had heard of the rollover mileage comments, but you will not find anything in the contract referencing any such provision. Having spent over 40 years in contract analysis, if it ain’t in writing, I will not depend on it. There is an old contract saying along the lines of, “a verbal agreement is not worth the paper it is written on”. I see by you comment about it not being well documented, that you were concerned about it, and I would agree with you.

 

[Frankie the Fink]

I don't disagree, perhaps its some sort of option like the 9-to-5 add on that lets you drive your collector car to work a couple of times a week. I'm not shilling for NCM, just noting I had a stellar experience with a large claim...

 

[rponfick]

I agree, I find NCM a great source of insurance, and I have two Thunderbirds with them.
What I do find strange is the rollover provision, which they verbally acknowledge, but which is not in any written contractural policy language. I prefer not to worry about ”corporate” denying a claim when some provision is not specifically enumerated in the contract.
Not arguing with you, but just expressing my concerns.

 

[Frankie the Fink]

A further word aboit brake drums. In tje good old days shops would pre arch tje brakes fot proper mating right from the start. Nobody does that anymore so itt takea a 150 miles or so to get full contact braking.

 

[jimntempe]

A further word aboit brake drums. In tje good old days shops would pre arch tje brakes fot proper mating right from the start. Nobody does that anymore so itt takea a 150 miles or so to get full contact braking.

That's true.. and irritating. When I looked at the descriptions of shoes most, if not all, of them said the shoes where ground to proper arc. What I ordered, from Centric, clearly had never ever been ground to anything. They obviously took the bulk lining of length, width, and thickness spec, bonded it to the shoes, and shipped em without ever grinding. In addition, the surface of the lining was somewhat rough rather than the smooth surface you see on well used linings. All of which made them a pain in the behind during the first many miles. I had to do a lot of manual filing to help with the seating-in process to get rid of high spots on the leading edge.

 

[rotter]

I will measure the drum thickness and go from there. Thanks for all of the input.

I am looking for brake drum specification for inspection- need our gal size thickness!
Thanks
Rotter

 

[55blacktie]

DOT 5 silicone brake fluid.

 

[rotter]

I need drum spec size thickness for 1956.

 

[74 Harley]

Your drums should be marked with" max diameter" followed by the numbers that are the maximum inside diameter. They aren't measured by wall thickness.

 

[knuckle47]

I did not measure … based on the discussions above with @Frankie the Fink , I just replaced them… but, I do have these pictures I found of my old and new drums side by side


Ps: also got a terrific quote from NCM