Oversized Brake Drums

V8COOPMAN said:
….only because it's ILLEGAL
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I suspect you'll have a hard time finding any federal or state laws that prohibit drums from being turned to an ID greater than .060" oversize.

Laws will be written to prohibit exceeding the drum/disc manufacturer's recommended minimum thickness, not some arbitrary measurement of .060" or such.

Manufacturer A's drums may only be able to be turned to 12.060", while Manufacturer B's drums may be able to be turned to 12.160".
 
Doesn't have much to do with Ford, there are state and federal laws that cover this. This applies to all brake drums (with some exceptions) on all vehicles. Why, because that is the design safety limits. Can you exceed these limits and get the brakes to work? Yep. Just like any safety limit there are designed in margins, the brakes are not going to fail at .061 over. I don't know what the safely margins are on brake drums, but typically safety margins run at least 2x or more. So .120 would work without total failure but would totally defeat the whole purpose of having safety limits.

The thickness of the drum has to do with lots of design elements, one bit one is heat dissipation. A problem with drum brakes is fade. With heavy use the drums heat up enough that they stop functioning correctly. The thinner the drums the quicker that occurs.

There are also issues with the shoes. The more the drum is enlarged over it's design diameter the poorer the match there is the shoe design diameter.
 
Seems like we are starting to get wrapped around the axle here with this thread (no pun intended). The bottom line is that there are specifications and limits pertaining to maximum allowable limits for brake drum over sizes. While I'm no expert here is some info regarding brakes which may or may not pertain to your situation.



The Federal Motor Carrier Safety Administration specifies requirements for trucks:
405 [FONT=&quot]Federal Motor Carrier Safety Administration[/FONT]
§ 393.47 Brake actuators, slack adjust-ers, linings/pads and drums/rotors.
[FONT=&quot] (g) Drums and rotors. The thickness of the drums or rotors shall not be less than the limits established by the brake drum or rotor manufacturer.
[/FONT]


California (as I'm sure other states as well) has requirements pertaining to vehicle brakes as well:



[FONT=&quot][/FONT]CALIFORNIA CODE OF REGULATIONS (CCR) SECTIONS 3300 THROUGH 3320]
[FONT=&quot][/FONT]

BUREAU OF AUTOMOTIVE REPAIR BRAKE ADJUSTERS’ HANDBOOK practicable with respect to the wheels on opposite sides of the vehicle.” The adjuster should not certify a vehicle if (1)any drum or rotor exceeds the vehicle or parts manufacturer's service limits, (2)the thickness of the brake lining (friction material) is found to be less than that specified by the manufacturer's service limits, (3) the vehicle fails to stop within the required distance, (4) the parking brake system is found to be inadequate or in operative, or (5) any other condition is found that would make the service braking system unsafe.


The key here is the manufacturer's specifications or limits. Seems clear to me, if your brake drums exceed manufacturer's you are pushing your luck and endangering others.
 
Branded said:
Never have I heard of anyone ever having someone wanting to measure brake drums for being overturned after an accident.
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In Illinois back in early 1980's, two folks were killed when a persons brakes failed and they were run over.
The person driving was eventually jailed. It was quite the sensation back then making a lot of the national news outlets.
It also changed a lot of ways of doing business.
No more oversize brake shoes were sold and no more "lesser quality" aka "economy" shoes / pads were sold to those trying to go "cheap". Only pads / shoes manufactured to the minimum required by the car maker were to be sold after that debacle.

So, now you have heard...
 
All this has me wondering. Is it possible that some unenlightened judge and jury might find someone driving a car with mechanical brakes liable for using outdated technology? In this litigenous society with super aggressive lawyers I wouldn't be surprised.
 
whether restoring from the ground up, or just trying to put an old car back on the road, i'm sure all of us are going to at least check, and go thru the brakes. but, when i look at all the badly worn drums in my stash, it seems they didnt much care. they just put new shoes in and out the door it went. most of what i have are .100 and bigger
 
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cas3 said:
whether restoring from the ground up, or just trying to put an old car back on the road, i'm sure all of us are going to at least check, and go thru the brakes. but, when i look at all the badly worn drums in my stash, it seems they didnt much care. they just put new shoes in and out the door it went. most of what i have are .100 and bigger
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So true. I have a few that are so badly grooved, there must not have been any lining material left and the rivets there doing the stopping.

I was just thinking to myself the other day, why in the world am I holding on to these things?
 
I just bought a complete rear axle for my '92 f350 dually from a wrecking yard. The linings were worn off long ago and the bare shoes were getting REALLY thin. Thankfully, I had just done a complete brake job with new drums on the axle that I was replacing. Who drives around like that in a loaded flatbed????? In other words, this type of hackery is still being commited today.
 
I have read on the HAMB or here that there is a company that will reline any drum back to new diameter. They were expensive but it might be with looking into.

John
 
Kube said:
In Illinois back in early 1980's, two folks were killed when a persons brakes failed and they were run over.
The person driving was eventually jailed. It was quite the sensation back then making a lot of the national news outlets.
It also changed a lot of ways of doing business.
No more oversize brake shoes were sold and no more "lesser quality" aka "economy" shoes / pads were sold to those trying to go "cheap". Only pads / shoes manufactured to the minimum required by the car maker were to be sold after that debacle.

So, now you have heard...
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Brakes can fail for many reasons, even driver ignorance. One big no no that people have done is compression fittings on brake lines. A parts store did not want to sell me some compression fittings and a piece of brake line until I explained I was fixing my transmission lines.
 
Pay attention to what V8 and others have advised. Don't cheat on your brakes.
Today's lawyers will hire "old car restoration" specialists who will do an "automotive autopsy", find faulty parts and even recreate a visual of the accident.
 
tubman said:
Is it possible that some unenlightened judge and jury might find someone driving a car with mechanical brakes liable for using outdated technology?
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In the same light, might that same ignorant judge.....scratch that....."unenlightened" judge also find your 'old-timey' drum brakes on the front of your '51 as qualifying for "outdated" also, in view of the fact that his wife's Mercedes and virtually all modern cars (that he has seen at the Country Club) have anti-skid & disc brakes, at least in the front? DD
 
V8COOPMAN said:
In the same light, might that same ignorant judge.....scratch that....."unenlightened" judge also find your 'old-timey' drum brakes on the front of your '51 as qualifying for "outdated" also, in view of the fact that his wife's Mercedes and virtually all modern cars (that he has seen at the Country Club) have anti-skid & disc brakes, at least in the front? DD
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Maybe, but drum brakes are still currently used on some models; mechanical brakes are not.

AND, if you are right, we are lost because we don't have ABS.
 
I bought my Ford pickup 27 years ago. It has disc/drum brakes.
Will there come a day when my insurance company can simply decide, "your truck's too old for us to insure any longer" as a daily driver even if all components function as new?
 

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'35 drums were one year only in the US. So good ones measuring less than 12.060" diameter, in the area where brake linings contact the drums, are difficult to find. Having/owning a number of '35 vehicles, I hold on to every good one I get my hands on. If the time ever came when I couldn't find good original '35 drums, I would not hesitate to use good original '40-'48 drums, along with ring spacers that properly support '35 wire wheels.
The 12.060 dia. limit was probably dictated to all licensed brake repair shops by law.
 
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over sizing brake drums has been a subject of great debate ever since they where invented as a licenced mechanic i use manufacturers spec as to max oversize and it stands up in court every time these days with 18 wheelers it costs more to oversize than to replace with new ones as for our oldies parts no longer grow wild so im an advocate of rebuilding drums with metal spray or sadly up gradeing to modern types lets face it i would rather stop in time than have a drum shatter and be a filler for a pine box
 
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