Brake drums

Bob/AZ

Bob/AZ

Senior Member
Does anyone know of a shop in eastern North Carolina that can turn Model A cast iron drums? Maybe in the Raleigh area? I called Randy Gross and he suggested that I get them turned here if possible because of the shipping cost to send them to him in CA.
I understand that the fronts can be done by most shops but the Model A rears are not so easy? BTW if anyone has a brake problem I would think Randy is the go to man. He was very helpful. Thanks, Bob
 
Turning cast drums shouldn't be a problem. A brake shop or a truck garage may have a brake lathe gathering dust in the corner somewhere.
 
The problem is that most brake lathes have an arbor that is much too big for the rear hub hole.Some,(but not all)old VW rear drum adapters work if you can find somebody who has one.I have a VW adapter that does not work on the A's.
 
Keith True said:
The problem is that most brake lathes have an arbor that is much too big for the rear hub hole.Some,(but not all)old VW rear drum adapters work if you can find somebody who has one.I have a VW adapter that does not work on the A's.
Click to expand...

That is why obsolete machinery is your friend! :)
 
Yep, I forget about the rear. Some arbors aren't skinny enough to fit. Front isn't a problem. A big enough lathe will work.
 
Even in the early-mid 70's when I was into Volkswagens it started to get a little difficult to get the rear drums done.Those machines saw a lot of use back then,but the days of the old Ford,Rambler,Studebaker were starting to fade into the past.Walk in customer service at a machine shop is a thing of the past now too.Everything they are doing is subcontract work for manufacturers.One small one near me will still do something like a drum,but it is $75.per hour,minimum one hour,if you can catch him between jobs.If he has to knock down a setup and set it up again just to do my job I have to pay for that time.I have no idea where I would go to get a trumpet turned now,the last guy I knew with a big old machine for those kind of jobs has passed away.
 
It's best if you can find someone with Barrett brake doktor lathe, the inner adapter fits into the wheel bearing with the seal in place assuring it is centered the same as running on the car
 
Probably not best to chuck in a standard lathe. It will be cut round, but chances are the cut surface will not be concentric with the hub where the axle goes. Best to use a brake lathe. Races must be installed and I would indicate the rear hub before turning.
 
An old rear axle that is cut off can be used on a lathe to machine the rear drums. A center point will steady the shaft and the nut can hold the drum on the axle. I tool post grinder with a small wheel would be the best tool to do the machining. Just make sure you do not take off too much material. I think the limit is 0.045 inch on the radius for a cast iron drum. Ford recommended new stamped drums instead of turning the stamped drums.
 
J Franklin said:
A machine shop should be able to chuck up a model A drum and machine it on a standard lathe.
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Umm, not really. At least not easily (-i.e.: inexpensively). They would need to chuck on the ID of the hub bearing race, which places the tool post on the wrong side to reach the lining surface. This is why a brake lathe and an engine lathe are totally different in their setups.

I will also share this is another area where if a shop does not specialize in Model-A brakes, they typically get this wrong. Most brake machines use cones to center on. Most of the hubs that I see have been damaged where the axle shaft washer was not used and the end of the hub is damaged where the cone would be used. If the drum is not installed onto the lathe in the exact centerline of the hub race (- not the axle shaft) you will have issues with the shoe linings matching the drum surface. It is also worth noting that many cast iron drums have been installed onto hubs that were not trued to the bearing centerlines. My advice is you need to find a shop that has the experience and the tooling to correctly install cast iron drums.
 
nkaminar said:
An old rear axle that is cut off can be used on a lathe to machine the rear drums. A center point will steady the shaft and the nut can hold the drum on the axle. I tool post grinder with a small wheel would be the best tool to do the machining.
Click to expand...

Ummm, I totally disagree with this Neil.
 
Well, I can get the fronts done here so I will do that and I guess I will probably send the rears to Randy. I'm getting the impression that even if I could find a machine shop that would do them I would feel better about having them done on a brake lathe. Thanks for all the input. Bob in NC
 
Bob,
As Brent mentioned there are a number of issues that can cause turning the rears to be if issue. Axle holes burred, if you use the hub surface that it too is ok. Few exhist but an expander adapter that fits inside the bearing surface as long as it’s in good shape. As Brent said if you use a cone you must ensure that it fits properly abs is centered. Mentioned above was leaving the seal in. Under no circumstances should that be. Even if you got a small cone to the inside of the hub it will be burred at the hub and you cannot ensure that no shavings don’t get in your grease and bearings.
This is a job left to someone who understands model A drums and brakes (all flathead Ford’s for that matter ) .

Just my 2 cents worth and trying to help make sure you don’t have issues. Hopefully somewhere nearby there’s someone to help.
Larry Shepard
 
The place I worked at in high school has an expander tool to fit in his brake lathe.It did look like a tailpipe expander,but it had a few more segments and it was precision machined.Instructions said to wash and oil before use.It was red,and was in a red tin box.I remember being warned to make sure it was seating properly on the bearing surface,and not on some rust on the snap ring lip.I remember on Fords the bearing surface was long enough that the expander reached in beyond the snap ring lip.
 
I always measure the cast iron type drum before considering a brake surface cutting process. Most shops will not refinish them if they are even close to .060" oversize and exhibit uneven surface wear. If they have a lot of meat left, at least it's worth the effort.

Ammco brake lathe units can be refitted with the 11/16" Arbor and used with proper mandrels but they require good surfaces to center up. Even the Barrett Drum Dokter can have problems if a hub is bad. Ford rear hubs can be problematic to center if they exhibit too much wear or damage. If so then a person may need to replace them with serviceable parts. An out of round drum wont work worth a damn.
 
OK, Brent, I see what you mean and retract my used axle idea. My mind must have been in the Model T mode.

In the past I have used expandable collets to mount ID surfaces. I machined them to match the ID. But it would be hard to get a tool post grinder or boaring bar on the head side of the lathe. Unless you made a really long collet and used the centering bearing on the tail stock.

Finding a brake shop that does Model A's is the best but may not be possible. After all, it has been over 90 years since the Model A's came out.

I wish I still had my little machine shop.
 
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Contact local Model A and Early V8 Clubs and see where they take them. Be sure you don't take them to someone that has never done it before.

Charlie Stephens
 
I'll go along with the wise people on here. I didn't read why the drums needed turning. I would only turn a drum if it was out of round or very deeply scored. Light scoring doesn't really impact braking after the first few stops as linings conform to the drum surface, my shop teacher said to our class. He mentioned it even give more braking surface.
 
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