Brake Drum turning spec.

[palmczak]

Does any one know how much can be taken off the brake drums before they get to thin? I have a set of shoes and drums at a brake specialty shop. They are relining the shoes and going to turn the drums and arc the relined shoes to the turned drums. They called and asked if I had any specs regarding how much could be taken off these drums one of the drums has some deep grooves and he was concerned taking enough off to remove the grooves would leave the drum to thin. The guy doing the work asked for the max inside diameter.

Also he asked if I cared if he bonded the new lining material to the shoe instead of riveting the lining on. He said there would be no rivets to gouge the drums if the shoes were worn to far. What are the downsides of bonding vs riveting the lining material to the shoes?



Thanks,

joe

[Lifer]

I don't know about the turning specs for the drums, but I can explain a little bit about the bonding/riveting question.

Back in my (much) younger days, all brake linings were riveted on. Then, along came bonded brake linings. Sometimes, the bonding agent would fail and the linings could come right off the shoes when the brakes were applied "aggressively." Not good!

With the riveted lining, sometimes the lining would crack and you would end up with chunks of lining falling off the shoes and collecting in the bottom of the drum. Also not good!

It has been a long time since bonded brakes were introduced, and I haven't heard of any instances of bonding failure in years. This is good!

My recommendations, then, are thus:
(1) if you want to do a "correct" restoration, go with riveted lining, and
(2) if you just want decent brakes, go with the bonded lining.

FWIW, bonding would probably be a little cheaper due to the fact that less labor would be required. It takes a while to set all those rivets!

[M-Thrax]

New drums are 14 1/8"., The book says 14 1/4" is maxed out., I'm sure you could strech that out a bit unless your planning on a fully loaded truck driving on a daily basis. Find a truck brake shop who can turn the drums with the hubs on, this will give a truer cut.

[DAP]

I have some (4) used brake drums for sale. Take offs so don't know condition and I have nothing to measure them with. They look good. They are sand blasted and treated with Wal-Mart Extend type spray on the outside. Only problem is they are heavy so shipping would be a killer. I am 30 minutes south of Charlotte, NC. Name your price and they are yours.

[palmczak]

thanks for the info.

Eventually this truck will get disks up front at least. But that process is going to take a bit longer than I wish to spend right now.

3 of the drums turned out just under 14.25" the remaining 1 is probably shot. I had them cut it to approx 14.275 to see how much of the grooves are still there. It may get re-installed, just so I can mount the wheels and tires. (I just got a set of 5 11x16 XL Michelins and it has been snowing for days I want to play a little)

I have most of the stuff accumulated to do a front disk conversion. Does anyone know if Helitool is converting hubs? I have heard that thay are not as of yet.

thanks again,

Joe

[MSeriesRebuild]

The problem with turned drums is this, even a new drum is thin, turning the .250" max of course thins them even more. They never give satisfactory service for very long. What happens is a couple of hard applications will heat then up to the point of warping because they are now so thin. When this happens, shoes are impossible to keep adjusted correctly & the warped drums will cause the brake pedal to be pushed back at you when brakes are applied. It is an absolute must to have the shoes adjusted exact in order to have good brakes with this type of system. The larger tires will multiply all the above listed factors making the need for a perfect functioning system an even bigger issue. With new or good take-off drums being very hard to come by, my suggestion would be don't spend $$$ now, but put it aside to go toward the far better disc system on all 4 wheels. I know this isn't good news when you think of playing in the snow, but neither is the realization of $$$ wasted down the road & still no good brakes.

[palmczak]

Thanks Charles.

I am ready to get the disks but did not think they were available. This set up is just temporary, until I can get a set of disk brakes installed. I doubt it will see 200 miles. It is really just so I can move the truck around, seems no matter where I work on it if it is difficult to move It is right in the way.

Joe

[ELBUFO]

A complete break job on my "new" M37 is on the to do list. A grooved drum is one of the things I am not looking forward to. Nothing is worse than a drum that has a rivet grove....Except being poor folk, and/or cheap. I have successfully "saved" many a drum by truing, and ignoring the grove, during my stretch working on Air Force vehicles, provided they weren't as deep as the grand canyon. Now for the lawyers...You didn't hear it from me! Do not do this at home...No user serviceable parts inside... The down side is a ridge will form on the shoes. This can make drum removal a little difficult unless you back off the shoe adjustment. I have a Willy's M38 with a groovy drum, that has been that way for 15 years. This particular drum was turned by NAPA. HOWEVER, in this sue happy time, they might not do it for you (under counter money helps here)... use at own risk...John

[palmczak]

I just received this email from Ray@uglytruckling. in regards to my inquiriy about the availability of disk conversion kits.

"I just shipped 150 sets back to the US they should be there by the end
of January. I will be flying back first part of Feb to handle the hub
conversion and shipping. I will email you instructions for shipping your
hubs when I get back to the US. It usually takes about a month to get your
hubs done and shipped back to you as we need to get enough of them together
to make it worth while to do a run.

Ray/Uglytruckling"


If anyone is looking to do a disk brake upgrade this is a good opportunity contact Ray so you are on his mailing list.

Thanks,

Joe