Brake Shoe Arcing

[stan35]

I just sent the brake shoes from my 1935 Cabriolet out to be relined with woven linings. The shop said that if I am going to have my drums turned then I should not need to have the shoes arced. He said that when I get the brakes back I should place them inside the drums and they should be a perfect fit. I have always read that the relined shoes should be arced to the drums. What should I do? As always, all responses are appreciated.

[Kube]

Arcing shoes is always prudent when the drums have been turned. Getting them arced these days can be challenging as most shops have long since gotten rid of the machine that did this.
Think of it this way: Once the drums are no longer the stock diameter, the shoes, being the stock diameter, will only contact the drum in a small area. If the shoes are arced to fit the drum as cut, they will have nearly 100% contact.

One additional problem often found with relined shoes (and new) is they are not "true". The shoes may be warped and the linings not applied "quite right". Arcing remedies these two common issues.

I speak from experience. My first state apprenticeship was as an automotive machinist. Arcing shoes was common place then and in fact included with a purchase of shoes and drums (turned). Later, I had my own thriving repair shop and would only install brake shoes that were arced. It was (is) amazing the difference in stopping performance when the brakes have been properly service (IE arced).

[mrtexas]

I just sent my model a backing plates and drums out. New shoes and drums were installed. The drums were trued to the hubs. The shoes were then arced. Believe it or not some material was taken off of the shoes.

Also installed new modern style drums on 40 hubs on the back of my 36 woodie with drum not swaged to hub and press on studs. Then put on new bendix backing plates and shoes. Shoes not arced and worked fine.

[Kurt in NJ]

When I send shoes out for relining I also include the drum diameter

The best way to "arc" the shoes on a fixed anchor system it with a Barrett brake doktor, this machine arcs the shoes on the car to the center of the axle ---it isn't a machine that is easy to find though

[Tim Brown]

Its not legal to Arc shoes here in California. The good news is its not that hard to find someone to break the law here in California.... I found someone that turned the drums and grind (arc) the shoes to match. It made a HUGE improvement. (Now why would our govt folks not want us to have good brakes on our cars..?)

[Kube]

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Originally Posted by Tim Brown

Its not legal to Arc shoes here in California. The good news is its not that hard to find someone to break the law here in California.... I found someone that turned the drums and grind (arc) the shoes to match. It made a HUGE improvement. (Now why would our govt folks not want us to have good brakes on our cars..?)

Actually the modern shoes can be arced legally as they no longer contain asbestos. However, most folks either don't know better and / or with the very limited use of brake "shoes" these days, most shops would not invest in the proper machine to do the arcing.

As you state, it does make a huge difference. Just doing the math would clearly indicate that result. More contact surface = better braking.

[Charlie Stephens]

Originally Posted by Tim Brown

Its not legal to Arc shoes here in California. The good news is its not that hard to find someone to break the law here in California.... I found someone that turned the drums and grind (arc) the shoes to match. It made a HUGE improvement. (Now why would our govt folks not want us to have good brakes on our cars..?)

I could be wrong on this since I haven’t followed it closely. I think it is legal to arc shoes in California. If you have a reference about it being illegal to arc brake shoes in California I would sure like to see it. All that is necessary is to find someone with a machine that meets all of the OSHA and AMQD requirements for capturing the dust. That is quite a challenge since disc brakes became popular about the same time the OSHA and AQMD requirements kicked in and disc brake pads don’t need to be arced. The machines that meet all of the OSHA and AMQD requirements are expensive and nobody invested in them since disc brakes were rapidly becoming the standard on newer cars. You are more likely to find a legal machine to arc brakes in a facility that relines shoes for a business than the corner brake shop that does one set of brakes using shoes in a month. It is using a machine that is not approved to arc the brake shoes that is what is illegal in California.

Charlie Stephens

[Charlie Stephens]

Originally Posted by stan35

I just sent the brake shoes from my 1935 Cabriolet out to be relined with woven linings. The shop said that if I am going to have my drums turned then I should not need to have the shoes arced. He said that when I get the brakes back I should place them inside the drums and they should be a perfect fit. I have always read that the relined shoes should be arced to the drums. What should I do? As always, all responses are appreciated.

This reminds me of the universal translator they had on the original Star Trek series. What was said was “You should not need to have the shoes arced”. What was really meant was “I don’t have the equipment and can’t sell you this service so I am just going to tell you that you don’t need it so you don’t take your business somewhere else”. Do you really need it, no but the brakes will work slightly better if you do it. After they wear in the problem goes away (assuming you don’t hit anything first). I would look for another shop, which may be difficult to find. Ask at your local Model A or Early Ford V8 club and see if they have any sources to get the work done. There is the outside chance that your drums were turned 12.030 and the company that manufactured the shoes arced all of their shoes to 12.030 when they arced them, you might inquire.

Charlie Stephens

[texas webb]

Originally Posted by Tim Brown

Its not legal to Arc shoes here in California. The good news is its not that hard to find someone to break the law here in California.... I found someone that turned the drums and grind (arc) the shoes to match. It made a HUGE improvement. (Now why would our govt folks not want us to have good brakes on our cars..?)

For the most part they don't care about us.

[V8COOPMAN]

Originally Posted by Tim Brown

(Now why would our govt folks not want us to have good brakes on our cars..?)

I honestly don't remember any state or Fed agency encouraging or promoting OLDER vehicle operation or usage, not to mention legislation to save recycling yards. "Cash for Clunkers" ring a bell? DD

[B-O-B]

Saw a bit on the news the other night about the government wanting to outlaw working on your own car. This was pertaining to newer vehicles with computers but I'm sure they would like to see all us old farts & our cars in museums.
I did my own woven linings & used a split sanding belt inside the drum then worked the shoe around the drum till it checked out . I could not find a shop to arc the shoes to the drum & most mechanics asked what I was talking about.
While we are talking about big brother the tax assessor showed up yesterday & wanted to check to see if we have a jacuzzi bathtub. I'm still pissed about that but the bride let him in to check while I was in the shop.

[ford38v8]

Originally Posted by B-O-B

...While we are talking about big brother the tax assessor showed up yesterday & wanted to check to see if we have a jacuzzi bathtub. I'm still pissed about that but the bride let him in to check while I was in the shop.

They do that in Oregon? Did your wife check his credentials? That sounds pretty far out to me.

[B-O-B]

Yes she did Alan. She saw it on the tax bill & complained & then the tax man cometh.
The worst part is my 30X40 shop was wide open so I do not know if he stuck his nose in there or not. I hope not. Hell they even got pictures of this place from the air. On another note when I was building a house in Cal, I had to go to the inspection dept for they where saying that the house was 75% complete & they were taxing me accordingly. I went in & told the guy that the counter tops were not even done . He said I know that. I said how do you know that? He said I was up there & looked in the windows. No matter where you go they all pretty much the same. A bunch of********.

[FlatheadTed]

You can chalk the drum then sand them with 60 in the vice until you get a pretty close fit .Ted

[Ralph Moore]

Originally Posted by B-O-B

Yes she did Alan. She saw it on the tax bill & complained & then the tax man cometh.
The worst part is my 30X40 shop was wide open so I do not know if he stuck his nose in there or not. I hope not. Hell they even got pictures of this place from the air. On another note when I was building a house in Cal, I had to go to the inspection dept for they where saying that the house was 75% complete & they were taxing me accordingly. I went in & told the guy that the counter tops were not even done . He said I know that. I said how do you know that? He said I was up there & looked in the windows. No matter where you go they all pretty much the same. A bunch of********.

Up here someone doing that kind of stuff is likely to get the buisness end of a 12 gauge.
But back on the subject, one of our car club members has an arcing machine and has offerd to do some shoes I'm putting on a 47 buisness coupe I'm working on. So new shoes, but do the drums need turning if they are not bad? I know it's better to have them turned, but I'm afraid turning them would just put them out of spec.

[Kube]

Originally Posted by Ralph Moore

Up here someone doing that kind of stuff is likely to get the buisness end of a 12 gauge.
But back on the subject, one of our car club members has an arcing machine and has offerd to do some shoes I'm putting on a 47 buisness coupe I'm working on. So new shoes, but do the drums need turning if they are not bad? I know it's better to have them turned, but I'm afraid turning them would just put them out of spec.

The closer the drums are to being actually round, the better of course. If they are nice as you believe they are, it should take very little to make them perfectly round. There is no rule that a machinist must take a first pass at .030". Tell him to go very easy on the first pass - maybe .010".

[Tim Brown]

We had a case locally, where a model A club member, asked another member that owns a repair shop, to do a brake job. The repair shop did the work, including arcing the shoes and installing asbestos linings. Once the job was done, the fellow turned him into the state. It turns out he also worked for the Calif Bureau of Automotive Repairs. The shop owner had to pay a 5k fine. Totally setup by the fellow club member. Most folks in this hobby are cool. Every now and then you run into a dickhead...

[Charlie Stephens]

Originally Posted by Tim Brown

We had a case locally, where a model A club member, asked another member that owns a repair shop, to do a brake job. The repair shop did the work, including arcing the shoes and installing asbestos linings. Once the job was done, the fellow turned him into the state. It turns out he also worked for the Calif Bureau of Automotive Repairs. The shop owner had to pay a 5k fine. Totally setup by the fellow club member. Most folks in this hobby are cool. Every now and then you run into a dickhead...

I sure hope that the story gets around to his friends in the car hobby. He may have to find a new hobby and hope the story doesn't follow him. Something about don't bite the hand that feeds you.

Charlie Stephens

[jake197000]

arcing the shoes makes a huge diff.solved many braking problems by doing so.just did drums on 66 mustang today to solve a brake pull.sometimes you get lucky.but even if it feels good,if you arc them you might be suprised at how much better it feels.

[stangblue]

I worked in a brake shop as a teenager. We used to call it scribing the shoes. Today it hard to find a shop to scribe shoes with asbestos. I just did mine with a belt sander. You usually only need to take a small amount of the lining down on top and bottom of the shoes to fit the drum to get a good contact surface. The woven material is so soft that they will seat themselves over time.

[v8nut]

I have found the best way to arc brakes shoes (If you don't have a proper machine to do it) is as follows. This applies if the shoes need a larger radius (or if you prefer, diameter) this is usually the case as the drums get turned to a larger and larger diameter. First find a heavy anvil. Then get a very heavy ball peen hammer. Mine is about 4 5/8" front to back of the head. It is marked *A4B for whatever that is worth. Place the web of the brake shoe on the anvil and give it a few very hard blows near the center with the ball peen end of the hammer. This will stretch the web and tend to make the shoe straighten out which gives it a larger radius. Try the shoe again in the drum. If it still rocks, repeat the hammer blows. I have had good luck with this method. It is fast, it is cheap, no dust, no loss of lining thickness. Jim in San Jose

[HCO41]

Stangblue, why would you take material off the top and bottom (ends). Unless I 've missed something, when the drum is turned (larger inside diameter), wouldn't the center of the shoe be higher and rock on the drum?
Has anyone ever used a press to do this?
Howard

[George/Maine]

I have always chamfered the both ends of lining on bench grinder. On a straight angle depth 1/8" back 1/2".
They will brake in ok.

[john in illinois]

We have a Napa store that does a lot of large truck brakes. Trucks still use drums. He has arced several club members model A shoes.

John

[AnthonyG]

Still being fairly new to the Early Ford V8 game, 2 yrs or so ( previously a motor head and machinist from the mid '60's to mid '70's ) I hadn't heard of arcing brake shoes's. I skim cut the drums on my '35 and installed new shoes as I would have done on any of the '60's / '70's cars i'd worked on. Didn't really think about it and just broke them in the same way with easy braking and slow going for a while. Did notice a little more muscle required for a couple hundred miles but fine after that. Was I just lucky? Is it that big a deal? Generally the same set-up as the '60's / '70's cars but mechanical? Sorry for the ignorance on the matter, just trying to understand why the normal wear-in as with the newer shoe'ed cars is a problem?

[JSeery]

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Originally Posted by AnthonyG

Still being fairly new to the Early Ford V8 game, 2 yrs or so ( previously a motor head and machinist from the mid '60's to mid '70's ) I hadn't heard of arcing brake shoes's. I skim cut the drums on my '35 and installed new shoes as I would have done on any of the '60's / '70's cars i'd worked on. Didn't really think about it and just broke them in the same way with easy braking and slow going for a while. Did notice a little more muscle required for a couple hundred miles but fine after that. Was I just lucky? Is it that big a deal? Generally the same set-up as the '60's / '70's cars but mechanical? Sorry for the ignorance on the matter, just trying to understand why the normal wear-in as with the newer shoe'ed cars is a problem?

Same thing, arcing them just shortens the brake-in period. Increased shoe contact area increases braking force and reduces braking effort.

[ford38v8]

Tony, I grew up in the 50's when only the rich kids could afford to have a shop do their brakes. Nobody in my recollection ever did anything but install the new shoes from Pep Boys and return the old shoes for deposit refund. Nobody had their drums turned either, and our new brakes would last at least until we either blew the engine or broadsided some old fart.

[HCO41]

I'm a 50's era driver and do-it-your-self fixer too. Never heard of arcing until this post. Thought I might try it until I read the last three posts. That's the way we all did it, in fact turning the drums was heard of but seldom done in our era. (We also had a little more umph in our legs).
Howard

[B-O-B]

I worked in a Flying A,& a Atlantic Richfield station in the early 60's in L B Cal & we had a brake doctor in both stations. We always arced the shoes to the drums. Brake jobs were pretty reasonable then also. We also checked tire pressure, cleaned the windshield & checked the oil without the customer having to ask for it. Habit I guess but while driving today I generally notic peoples tires with low air pressure. You would be amazed at the ones you see with a door ajar, low tire or burned out taillights.

[ford38v8]

Originally Posted by B-O-B

I worked in a Flying A,& a Atlantic Richfield station in the early 60's in L B Cal & we had a brake doctor in both stations. We always arced the shoes to the drums. Brake jobs were pretty reasonable then also. We also checked tire pressure, cleaned the windshield & checked the oil without the customer having to ask for it. Habit I guess but while driving today I generally notic peoples tires with low air pressure. You would be amazed at the ones you see with a door ajar, low tire or burned out taillights.

Bob, Please understand that without implying anything about you, in my experience of the good old days, Service Station employees were encouraged by the owners to sell products and services by any means possible. This of course would mean overfilled crankcases, fan belts needlessly replaced, and a host of other more creative "sales" techniques, a couple of the most popular being the "dead" battery cell, and the "free" brake check.

[klawockvet]

Hmmm? I've been using the Ford automatic brake arcing machine for years. I think it was standard on all Ford cars until the advent of disc brakes. I take a new set of shoes and install them. Then I drive the car for a while and readjust the brakes. I think they are automatically arced to the drums when the brakes are applied. Its worked for me for the last 59 years. LOL

[B-O-B]

Alan could happen & I think 60 minutes did a show on it where they squirted oil on shocks BUT not where I worked. We had plenty of work doing it honestly & mostly repeat customers.

[Kube]

Ya know, there are of course numerous ways to do any particular job. While many approaches will work, some are simply better than others. I had a lot of formal schooling in automotive repair and had been certified (ASE) in brake repair.
I would never have thought to do a drum brake job without turning the drums and arcing the shoes. Was it necessary? No, of course not. Did I turn out optimal brake jobs? Yes, without question.

[AnthonyG]

Feeling better know knowing many changed the shoe's and took for granted a break-in period either not knowing or not bothering to arc the shoes and just broke them in till they made full contact, as did I. Initially after reading the first 10 or so posts thought I'd missed something in my glory motor head mechanic years, lol. The discussion was / is interesting and really quite informative. I go along with Alan and think as many of the practices at the Carfixer's garage that while the Idea and the practice was theoretically sound it was a bit of over-kill by the ford dealers and local Carfixers to get a few more bucks or justify the price for the brake jobs. Being an old machinist I'd love to see the machine though.

[B-O-B]

Well to each his own but I will continue to check my drums for out of round & turn them & arc the shoes to fit.That is the way I was taught. Did you folks ever notice your brake pedal moving in & out a bit when you applied them. Basically on mechanical brakes.

[ford38v8]

Bob, You are of course correct, and we do need every advantage we can get to protect ourselves and others while driving these mobile museums.

[Chisel]

Originally Posted by AnthonyG

Being an old machinist I'd love to see the machine though.

Picture of Ammco 8000

[Don]

Was in Hillsville WVa.last week at a old service station a guy had restored and had every piece of old automotive tool and machinery of the 30 to 60 and I saw that very machine,didn't think to ask if he would sell it..

[Kurt in NJ]

Brake doktor on 1930 Chrysler -- great for fixed anchor shoes, centers and arcs at the same time

[JSeery]

Originally Posted by Kurt in NJ

Brake doktor on 1930 Chrysler -- great for fixed anchor shoes, centers and arcs at the same time

That looks like a cool setup!