What is the maximum....

[Mr. Belvedere]

brake drum diameter? I have a 54 Plym 4 door. I can't find a spec stamped on the drum or in the shop manual I have. I assume it is 10.060 but thats just a guess based on previous experiances. Does anyone know for sure?

[Young Ed]

I think these old drums were a lot thicker so they would last. I believe someone mentioned they can be turned until it hits the little square dimples around the edge of the drum.

[Mr. Belvedere]

I am wondering if the shop will even turn them without knowing the limit.

[Normspeed]

I got a line on a shop in the Long Beach area that apparently still does the older brake stuff. I also have some drums that need to be turned if they have enough metal left. I'll let you know what I find out if I get down that way.

Also, on the back edge of the drums there is a line scribed into the metal. You might need to use some steel wool or sandpaper to spot it. Someone way back said they thought that line indicated the thinnest you could turn a Mopar drum.

[Plymouthy Adams]

If you were to wire brush the drums very good..the max limit should be stamped on it somewhere...saw this with the last set I sold...

[randroid]

Norm,

I'm the one who started that rumor and I'll stand by it, lol. My source was a grizzled old retired mechanic who did the machine work for the local Checker Auto Parts store (of all places).

He showed me the groove around the perimeter of the drum that's more easily felt with your thumbnail than seen with your naked eye, explaining that when the groove was gone the drum wasn't to be turned anymore. Not too many mechanics had the sort of micrometers that would be needed for accurate measurement back in post-depression shops, so WPC made life easier for them by using the groove instead of stamping a measurement.

I believe him, for why else would the groove have been machined into the drum?

Hope this helps.

-Randy

[blueskies]

Carefull not to turn them too much...

I had a drum seperate on my '53 chevy about 15 years ago, slowing to make a left hand turn off of a highway onto a side road. The right hand drum broke, serperating the "ring" from the "face". Suddenly there was only one front brake, and we turned toward oncoming traffic very suddenly...

Don't think I'll ever forget that...

Pete

[Mr. Belvedere]

Well, I cleaned the drums good, still no spec.... Does any body know why on earth front hubs on old rear wheel drive cars are always packed with grease? I have never quite understood this, what good does it do? Seems to me it just sits there in a big caked up wad unused. I don't recall ever reading in a manual anywhere that you should fill the hub with grease. I cleaned and repacked my bearings but I did not refill the hub with grease, the grease I cleaned out looked like it had been in there since the mid fifties very thick and caked. BTW, never got anyone to tell me what exactly the difference is between long fiber and short fiber grease is, I dont see anything in the parts store called long fiber or short fiber grease?

[Norm's Coupe]

I don't know what the spec's are as to how much can be removed from a drum. However, I was once told that the cut in the drum just before the outer edge is a guide for that. If you cut the drum down even with that cut, it can't be cut anymore.

As for why all the grease, that's in the service manual.

In many products like the grease the difference in long fiber and short fiber is for strength and application reasons. The shorter the fiber the easier it is to pump through a gun. Longer fibers will stop up the gun nozzles. Another reason for fibers to begin with is to hold the product together so it doesn't sag. The more fiber you have, the less sag, but then the less penetration of that product. You have to get the happy medium. To get the difference in long and short fiber grease, check some grease manufacturers info on the web. They should explain the difference there.

P.S. Just because you can't see the fiber in a product doesn't mean it isn't in there. In many products they use finely ground micro fibers not visible to the naked eye.

[Normspeed]

Mr. B, that tub of wheel bearing grease you mentioned in one of my transmission pics is medium fiber according to the label. I usually go by application when I'm buying the stuff, making sure I use a high temp WB grease for disk brake assemblies and more traditional WB grease for drum brakes. I usually put a pretty good glob of extra in the hub, just always did it that way.

[James_Douglas]

I had the opportunity to talk with someone a long time ago that worked on brakes at Chrysler.

He said that the .060 oversize was arrived at by taking the "real limit" and cutting that in half and then taking that and cutting that in half again.

He stated that he felt you could do .080 or even .1 if you are not racing the car all the time and check it for cracks every six months (daily driving).

I have used .080 on my early Chrysler 300's in the past, but I checked them every six months without fail. The big problem is finding brake shoes with enough material to get a grind on then at anything over .060. If they are too small then the brakes won't work that well.

As to turning them, I just told the local shop that there are for off road use only and signed the receipt for the work that had that written on it.

The information just given is for historical purposes only.

James

[bob_amos]

Norm, Drop on by my shop on your next trip and we'll cut those drums for you. As long as they have enough meat left on them we can do it. On page 44 of the '46 - '54 factory service manual it says that .060 is the maximim cut on the drums. Richard, my offer to cut the drums is also extended to you. If you are going to be in the Riverside area bring the drums along and I'll have them cut for you. We have a brake lathe in the shop.

[55 Fargo]

brake drum diameter? I have a 54 Plym 4 door. I can't find a spec stamped on the drum or in the shop manual I have. I assume it is 10.060 but thats just a guess based on previous experiances. Does anyone know for sure?

Well, at least in my province in Canada, rule of thumb is .060 over, and on trucks .090 over. That means the drums could be machined out .030, for a total of .060.

Best bet,, check with your state DMV on there inspections, if they have a requirement in your state or county. Get a measurement and go from there.

If you need a drum, others have located them on this website. I have heard of drums being spraywelded, then re-machined to spec, not sure if this is a viable option or not........Fred

[Normspeed]

Thanks Bob, I'll take you up on that. Awfully hard to find anyone who will work with the old stuff.

[Mr. Belvedere]

Well they miked mine at my local Star Auto, and said that they didn't look like they had ever been turned based on the measurement they took. So they went ahead and turned them and charged me $6.00 each. BTW, they did not have the spec either but I guess the measurement was very close to 10" even, so they figured it was ok to cut 'em.

[bob_amos]

Norm, Give me a call when you are thinking of coming by the shop. I just want to be sure you show up when I am there. (951) 354-5631.

[Normspeed]

Great, will do.