Arc grinding brake shoes

[AnthonyG]

Hi Guys, I’m ready to install new brake shoes on ‘47 rear brakes. I’ve got new stock brake linings, so the dilemma of finding someone w a brake shoe arc grinder is here ! I can’t find anyone in my area! I’m thinking as there new shoes being new new stock just break in as they S/B pretty close to round as they probably use modern mfg techniques like newer bendix type? I have Lincoln Bendix style in front so they are like the more modern cars w drum brake & not required. I found out the reason the old Lockheed non bendix brake shoes r so available & fairly cheap is they’re used on a lot of trailers w brake systems per a NAPA guy. Ideas please?

[Lawson Cox]

You need to find someone with a brake grinding machine if possible. My 2¢.

[Tim Ayers]

Originally Posted by AnthonyG

Hi Guys, I’m ready to install new brake shoes on ‘47 rear brakes. I’ve got new stock brake linings, so the dilemma of finding someone w a brake shoe arc grinder is here ! I can’t find anyone in my area! I’m thinking as there new shoes being new new stock just break in as they S/B pretty close to round as they probably use modern mfg techniques like newer bendix type? I have Lincoln Bendix style in front so they are like the more modern cars w drum brake & not required. I found out the reason the old Lockheed non bendix brake shoes r so available & fairly cheap is they’re used on a lot of trailers w brake systems per a NAPA guy. Ideas please?

Have you place them up next to the drum liner to see if they are actually off?

Even after having my shoes arched, I needed to do some final sanding to get them right.

To do this, I ran old fashioned chalk board chalk over the shoes. Spun the drum a few times and applied the brakes. This will tell you where the high spots are.

I carefully sanded them down until no chalk remained on the shoes when testing.

[V8COOPMAN]

Originally Posted by AnthonyG

I found out the reason the old Lockheed non bendix brake shoes r so available & fairly cheap is they’re used on a lot of trailers w brake systems per a NAPA guy. Ideas please?

Anthony ..... I think your NAPA guy has been smokin' some old brake shoe linings.

To 'ARC' your new brake linings, put your shoes in a box and ship to the folks below in northern Illinois. You will need to beg, borrow or steal a precision drum gauge and accurately measure the inside diameter of your new drums. These guys will arc your rear shoes to the diameter that you measure.

J&G Brake Drum Relining & Refurbishing

https://www.jgrelining.com/


815-276-2578

Our Mailing Address is:
212 N. Green Street
McHenry, IL. 60050


Coop

.

[flatford8]

The area where the chalk remained, wouldn’t that be the spots that weren’t touching the drum?.....then sand the area where the chalk rubbed off ...(the high spots)..... just asking to be sure I’m clear......thanks....Mark

[tubman]

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Never did it.

Never had to.

Never had a problem.

[Tim Ayers]

Originally Posted by flatford8

The area where the chalk remained, wouldn’t that be the spots that weren’t touching the drum?.....then sand the area where the chalk rubbed off ...(the high spots)..... just asking to be sure I’m clear......thanks....Mark

Mark: Yes. thank you for correcting me. Long day. I edited my post.

Thanks, I appreciate you catching that error.

[Ed Northrop]

I have done the same thing chalk and a hand sanding block works good .

[CA Victoria]

Sam @ Rochester Clutch & Brake
585-924-3717

Ask Sams thoughts on the brake lining hardness for the two different brake systems you are using. I’m using woven lining on my 46-48 brakes arched into new drums and it stops really well. The bonded linings were to hard.

[pistonbroke]

I'm remembering someone here at the Barn used adhesive sand paper in his drums and lightly applied the brake while the drum was turning. It sounded like it would work though the shoe would be about .060 smaller diameter then the drum due to the paper thickness.
Just saying I do pay attention to what I read here, Tim

[Dan McEachern]

Moose Motors
Pengrove, Ca

can arc your shoes

[Kurt in NJ]

For fixed anchor shoes a Barrett brake doktor is the best way to arc the shoes because it also arcs to the center of the axle too, it came with fixtures to hold semi floating and bendix type too.
when our cars were everyday drivers the less than perfect fitting shoes wore in after a while, it could take several thousand miles, most times that can be years of driving for many of these cars now, with properly arced shoes the fit is worn in perfect in a few stops.
I recently fitted a set of new production shoes into mustang drums, the box claimed they were pre arced to size, it became obvious on the arcing machine that there were sections of the lining that were ground to many different radius.

[Charlie Stephens]

Try asking this question at your local Early Ford V8 and Model A clubs, they must be having them done somewhere. Worst case sent them back to whoever lined them along with your drum diameters, they should be able to do it.

Charlie Stephens

[Mart]

I've used sandpaper in the drum and manually stroked the shoe back and forth in the drum. It gets it close enough so the rest can be taken of by a careful bedding in procedure. By that I mean gentle and often brake applications and readjustments in the first few miles. Just common sense stuff.

[Flathead Fever]

They still had an Ammco brake shoe grinder when I first started at the phone company garage. Then around 1984 Osha had them all removed because of the airborne asbestos they created. It was a $5000.00 a day fine if they found one in your shop. Nobody would buy a used one. The only thing you could do was take it home and hide it. The phone company through all of theirs away.

In the days of four-wheel drum brakes it was important that drums on the same axle be machined to within .010 of each other and the lining ground for 100% contact. This was especially important on the front brakes so the vehicles would stop evenly and not pull to the side with more lining contact or even the side with a slightly larger drum diameter. When front disc brakes came along it wasn't as important to grind shoes because the disc brakes on the front kept the vehicle stopping straight.

A modern drum could be machined to a limit of .060, example, they are stamped maximum diameter 12.060". That is not the maximum you can machine them to, it is the maximum diameter they can be without be discarded. Any larger than that and the drum can distort under breaking. Standard diameter to .060" over is also close enough that new shoes, although not contacting perfectly to the drum are still safe. They will eventually wear to the diameter of the drum, but this can take a long time. On a collector car you might never drive far enough to seat those shoes to the drums.

At work we installed thousands of rear shoes that way without any problems but that was with front disc brakes to keep them stopping straight. After a brake job we always rode tested them and let go of the steering wheel to make sure they stopped straight. For a drum brake car to be able to do the same everything must be identical. The tires need to have the same amount of wear, tire pressure the same, alignment the same as of course the brakes identical on both sides. Plus, four-wheel drum brakes need all the linings contacting the drums. Sometime even the rear tires and brakes can make it stop uneven. It still going to stop and be safe, but it won't be as good as it could be without matching the shoes to the drums.

I have two of those grinders I've picked up over the year but I have never used them. I collected cars and parts for my retirement years. While I was still working as a mechanic the LAST thing I wanted to do was work on cars at home. I started on a '34 pickup project. I bought new front Lincoln brakes and shoes and the shoes fit perfectly to the drums. Eventually I'll probably have to grind the rear shoes. I even bought a 5/8" tapered arbor for my brake lathe so I can machine the rear drums if I need to.

Set your shoe in the drum and see what kind of contact you have. More than likely it will hit in the center and rock back and forth. I have never tried this but if you were to apply automotive contact cement like Gasgacnch to the drum and a strip of sandpaper, maybe 220 grit. Use a piece of the thin autobody speed file paper. Let the glue dry an both surfaces and then stick the paper to the drum The glue will hold the paper to the drum and you can sand the center of the lining and then check the fit against the other half of the drum. You're not going to get it perfect because of the thickness of the sandpaper but it will be close.

[FlatheadTed]

Check out my Video here it shows how you can treat your drums with soldering fluid (Hydrochloric acid ) ,get a good coating of rust on them ,about a weeks treatment . Then assemble your shoes and ride the pedal for a nice burnishing /Honing action ,wash it out with baking soda,
https://www.youtube.com/watch?v=lcJ5LUbmro0

[Scotty's 52 F3]

X2 What Mart said.

[my4dv8]

40 grit Self adhesive sand paper stuck to the drum . Turn the adjuster so it allows the drum to fit over the paper then tighten the adjuster till you feel a slight bind , replace the wheel and rotate the wheel. You have far more control over this simple method. It worked for me with supposedly matching new drums and shoes. The hillbilly re arcing came out perfect.

[FlatheadTed]

I first tried the sand paper glueing 4 drums it gets it close but I found my treatment method gets the shoe the same size as the drum , one coating of acid then water each day ,wire brush it out ,after and soda wash , Ted

[frnkeore]

Yes, use 40 grit, 220 will clog, really fast.

As a mechanic, in the 60's, I also did a lot of brake jobs and the shoe arcing machines had a wheel that was way courser that 40 grit. It looked like small chunks of carbide soldered to a drum.