arching brake shoes,

[Fordestes]

I am donig the brakes on my 30 coupe, It has been around 50 years since I arched a set of shoes to the drums, My memory tells me to mic the drum, set machine to said diameter and back off the thimble adjustment about .006 leaving a small clearance on the heel and toe of the shoes to allow for anchored ends to expand to the drum, Is that the correct procedure ? I own a nice Shepard and Thomason commercial grinding machine, I havn't used it as I said for around 50 years ,it still works ok but never needed to arch any shoes. I would rather ask a dumb question than ruin a set of expensive linings. Thanks

[nkaminar]

Where are you located? I am sure a bunch of people on this site would also like to arch their brake shoes.

I believe you have the correct procedure but the best person to ask is Brent Terry. He is on this site so he may jump in. If he doesn't I will PM you with his contact information.

It is also important to have the shoes centered. There are tools available from the vendors for checking that. The Flat Head Ted kit allows the front shoes to float so centering is not as important.

You may want to grind or sand a small slope on the heals and toes as this helps prevent squealing.

[rotorwrench]

Your reasoning sounds good to me. Most folks would pay Randy Gross' price to do that stuff. There may be a few folks that can answer your question so I'll leave it to them.

[Jim Mason]

Ammco instructions. The offset is built in to the ammco, so you set at tge drum measurement. Don't know about yours

[Fordestes]

Originally Posted by nkaminar

Where are you located? I am sure a bunch of people on this site would also like to arch their brake shoes.

I believe you have the correct procedure but the best person to ask is Brent Terry. He is on this site so he may jump in. If he doesn't I will PM you with his contact information.

It is also important to have the shoes centered. There are tools available from the vendors for checking that. The Flat Head Ted kit allows the front shoes to float so centering is not as important.

You may want to grind or sand a small slope on the heals and toes as this helps prevent squealing.

I am aware of the centering and tapering the ends, it is the fine adjustment I cant remember , I just don't want to screw up my high dollar linings . as I said I remember something about backing off the thimble a few thou .

[Fordestes]

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Jim Mason, Thanks for the info. I see where I came up with the .006 heel and toe clearance, I was on the right track but couldnt remember the small details, I am in central okla if anyone needs to use the machine, it is in great shape and it is a commercial duty floor standing type. I also have a perfect circle brand piston knurlizer .

[mcgarrett]

Jim Mason,
I have that exact Ammco brake arching machine, but sadly don't have any of the gauge plates mentioned in the instruction sheet. Guess my machine won't do a proper job of arching shoes without them. Wish I knew where I could get a set of them.

[larry harding]

i have a friend who runs a garage near me and specializes in brake work. he says he never grinds brake shoes, but lets the shoes wear in. most brakes are disc now anyway. i think these machines were practically outlawed due to asbestos dust. the local "a" guru gave me his old grinder but i've only used it a time or two. to grind or wear in is a personal choice

[Jim Mason]

Originally Posted by mcgarrett

Jim Mason,
I have that exact Ammco brake arching machine, but sadly don't have any of the gauge plates mentioned in the instruction sheet. Guess my machine won't do a proper job of arching shoes without them. Wish I knew where I could get a set of them.

You can still use it with one of the other shoe clamps.

[ndnchf]

An interesting topic that reminds me that I have a Barrett brake shoe riveting machine and brake shoe grinder. I've used the riveting machine, but never could figure out the shoe grinder part. It has a sanding drum and an adjustable guide. I does not seem to be as precision as other machines. But could still be useful.

[Kurt in NJ]

arcing to drum diameter and centering at same time, Barrett brake doktor

[nkaminar]

Years ago I met an owner in South Carolina and drove with him in his Model A. I commented on how good his brakes were. He said that after installing new shoes he would ride the brakes until they seated to the drums.

[Dave N.]

This mite help someone , These are a copy drawings of the gauge plates for the Ammco brake arching machine The ruler is copied on the page so you can scale it correctly.

[dmar836]

So does the Brake Doctor grind the linings while the roller pins are resting on the centering tabs? If so, isn't that just altering good, new parts to fit onto old, damaged parts?

[BRENT in 10-uh-C]

Originally Posted by dmar836

So does the Brake Doctor grind the linings while the roller pins are resting on the centering tabs? If so, isn't that just altering good, new parts to fit onto old, damaged parts?

Yes it is. On the rear brakes it is a little more forgiving however the issue there is if the housing race is worn on the bottom side, the Brake Doktor is registering on the 8:00 to 4:00 area but does not account for the wear that is generally found in the 5:00 to 7:00 area. When this is worn, the hub roller bearing rides out of centerline which effectively raises the drum by 0.030" or more. The Brake Doktor cannot compensate for that.

[BRENT in 10-uh-C]

Originally Posted by nkaminar

Years ago I met an owner in South Carolina and drove with him in his Model A. I commented on how good his brakes were. He said that after installing new shoes he would ride the brakes until they seated to the drums.

Two thoughts on this, ...if the friction surface of the brake drum was machined extra rough to be able to grind away the lining material, then I can see how that would work however how does the brake drum know when to keep wearing off lining material? My guess it would go thru a lining fairly quickly.

Alternately, if the friction surface of the drum had a decent RA finish, then all riding the brakes will do is overheat the linings as it is trying to wear in ...thus causing the lining to either burn, -or at a minimum glaze over. At that point, the linings would not have the same amount of coefficient of friction, which would probably be the same as not having good brakes. Neither of his methods seems proper.

[Fordestes]

I just received some info on the question I had about the brake shoe grinder, the shoes are to be ground .030 under the diameter of the drum and a .006/.010 clearance at the heel and toe of the shoes to allow for expansion at pressure point/anchor points allowing full shoe contact at the drum when brakes are applied.

[Bob Bidonde]

I custom fit relined brake shoes using the technique noted in the slide below. It is easy to do and this technique optimizes the fit of the shoes to the idiosyncrasies of the brakes on my cars.

[Merc Cruzer]

Originally Posted by bob bidonde

i custom fit relined brake shoes using the technique noted in the slide below. It is easy to do and this technique optimizes the fit of the shoes to the idiosyncrasies of the brakes on my cars.

(x2)