arched brake shoes

[steammech50]

Was wondering why you could not arch brake shoes before you put on the lineing,jus to save a little more brake,or is this a dumb question !

[ABento]

The arch of the shoe needs to corrospond with the diameter of the drum, so when turning the drum to smooth it up you change the diameter, so the only way to correct for this is too grind off a little lineing.

[1930artdeco]

That is how dad does it. We would put the lining on the shoe, then in the drum by hand. Next we would take a feeler gauge and measure the gaps and add shim stock that I got at a hobby store. After playing with them a bit we would get them pretty darn close. Then when arched it was only just little bit shaved off or we could let them wear in.

Mike

[steammech50]

I take it you placed the shim between the lineing & the shoe ?

[just plain bill]

Arc, Arced!

[steammech50]

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Originally Posted by just plain bill

Arc, Arced!

????

[Tom Wesenberg]

Originally Posted by steammech50

????

Bill was just pointing out that the correct term is ARC rather than ARCH.

[1930artdeco]

Yes you do. I think that shim stock is .010" so we just built up the low spots. Make sure that the drums have been turned or are otherwise in good shape. We started in the middle and worked are way toward the edge. Then we just rivet and done. This just cuts done the amount of material that needs to be shaved off in the machine. Hope this helps, if you have any other questions shoot me an email and I will do what I can.

Mike

[pooch]

How long are the rivets that come with the standard 3/16th linings from Brattons?

I have relined my drums with 1/8 th steel bands inside.

After turning they are about 10 7/8th dia.

I am going to have to shim the middle of the arc out , so hope the rivets are long enough.

I am yet to find out if I will have any problems with the shoes being too far in towards the cams/wedges.

The linings have not arrived yet.

I know it is a big exercise and some will say. just buy new drums!

But it seems only Brattons has the early AR ones and they wanted $260 just to ship 4, and $125 each.

I welded the band in and machined them in less than 1 hour each.

So, if it doesn't work, I have not lost much.

The drums were so worn , they were scrap anyway, and at least I have "restored" and saved an original part. (hopefully).

[Jim Parker Toronto]

POOCH, Please let us know how it works out. You have put a lot of effort into it and I hope it will work for you. The only problem I see is the centers for the roller tracks and the sockets for the brake adjusting pin are in a fixed plane on the arc of the circle. Like you say, not much money invested, and time is gone anyway, so keep on machining!

[Tom Wesenberg]

I'm wondering about heat transfer, especially with such a thin liner.

[pooch]

Originally Posted by Tom Wesenberg

I'm wondering about heat transfer, especially with such a thin liner.

Yet to find out.

I machined the drum first, then rolled a hoop, then sandblasted the outside surface, so had clean metal to mate surface to surface.

Pressed liner in, and stitch welded around and around until it is fully welded each side of hoop.

I was toying with the idea if putting heat transfer paste in between, but did not.

I am hoping the closeness of the metal and the welds will transfer enough heat.

At least they should not expand with heat as they are now thicker than original.

Will use a laser gun to check temps when all is done.

I am installing the soft woven linings.

[Mike V. Florida]

If yo look at the cross section of a brake shoe you will notice that it makes a letter "T" with the top of the T where the lining is placed.

I have read that some pople use sheet metal shrinking\streching techniques to change the arch of the top of the T.

I hace seen some shoes with a ripple in this area and some with none.

[pooch]

Mike , I was thinking of re-arcing the metal shoe itself, but did not want to modify a good original part in case this does not work.

[kenparker]

Pooch, I relined my AR brake drums like you did, with a 1/8" thick rolled insert almost 12 years ago. I tack welded them into place like you did, then added the aftermarket Brake Reinforcing Bands, then had them turned to the original 11" dia. If you leave then the 10 7/8" your brake shoe linings will not fit and will have to grind then thin, and will have lost over 1/2 of your shoe material.

My original drums were less than .050 thick material when i started. Needless to say I had no brakes. After all the rebuilding my new brakes were not much better than when I started.. Part of the problem is/was the seam in the new rolled liner would wear the shoes very rapidly - even after grinding the weld to a resessed V. And the brake fade wasnt much better than before.

I am finally replacing the marginal drums with new Brattons AR drums this spring.

[sonny30coupe]

Pooch, you can not arc the shoe itself. You cant bend the shoe, to put shims in I would think would leave voids between where the shims are and where there is no shim next to it between the shoe and lining. Unless you shim the whole shoe, you wont have an accurate arc. While the feeler gauge may not fit between the lining and drum, you may be able to slip that feeler gauge in behind the shoe and lining, causing the lining to not be in full contact with the drum anyway. Shims are not right in my opinion. You may be using an original drum but you have not restored it. That would have been bringing back to original. It has been cut on, so now it is an altered part that would probably not be safe at this point, no matter what bands you weld on. They will still be too thin and not dissipate the heat.Some parts wear out. Sounds like for safety's sake, (yours, your passengers, and others on the road) you may want to buck up and pay for those new drums, if you are going to drive the car. JMO

[Arlyn Bieber]

Here is the procedure I have used with great success. Machine or true NEW brake drums. Rivet the linings to the brake shoes then bend the shoes to match the curvature of the newly machined brake drum. With the proper tools the shoes bend easily. After you have bent the shoes, arc the shoes using a brake arcing machine. Using this method only a very small amount of lining is sanded off. I also suggest if you drive your Model A throw away those old original brake drums. 99% of the drums have been machined several times. The metal is thin and will fade. Buy the new 1/4" thick drums and swage them on the original hubs. You can buy a set of these new drums here on the west coast for less than $300. Why risk your Model A investment, your life and the lives of your Model A friends on a set of worn out 80 year old drums. Maybe these worked fine when new and the road conditions restricted your speed to 35mph. Today we drive 50-60mph so it is a different ball game. Also restore the entire braking system not just new drums. The mechanical braking system when restored properly with do an excellent job of stopping the Model A but get rid of those old worn out drums. This is my story and I'm sticking to it!!

[pooch]

If you can point me where to get a set of AR drums on the west coast for 300 bucks. please do so.

I will carry them back as excess baggage.

So fer, i have only found later drums besides brattons.

[pooch]

Ken, That was why I did not machine back to 11 inches, left it thicker, and mine are fully welded both sides of band, I can understand a very thin band tacked in probably would not work.

Sonny and Arlyn disagree about being able to re-arc the shoe.

Also, the not restoring is a bit of a put down, if one was to re-sleeve a cylinder bore, would you also call that "not restored".

These drums WERE scrap, so no big deal on spending some time on them, we don't all live next door to brattons to pop in and afford new drums.

I am planning on shimming the lining with a solid piece of aluminium tapered at each end and not separate pieces of shim stock.

[Kevin in NJ]

Aluminum is not likely to be a good choice.

A little moisture and we have a battery with the two different metals and the AL corrodes and swells. I guess that could be looked at as self adjusting brakes.