Hi Folks, Having trouble with my brakes - just not stopping quick enough. A friend gave me a hand to have a look and it appears the shoes are only touching the drums in small contact patches near the ends of the shoe. It looks as if the drums have been machined out and the arc of the shoes is now incorrect for the drum diameter. Here's what I have: 1940 Ford hubs 1937 Ford Spindles 1939 Lincoln Zephyr backing plates 1956 Buick 45 fin drums Now re-radiusing the shoes is something I've heard about, but no-one in Scotland knows anything about that. What are my options? Does anyone do repro drums? Can I simply put longer actuating rods in the wheel cylinders to bring the top of the shoes out? Help!
Used to be, in days-gone-by, when you had your drums turned, the parts-guy "arced" your new shoes to match the "new" diameter of your just-turned brake drum. I guess with the advent of disc brakes AND regs from the asbestos police, the arcing of brake shoes has almost disappeared. Without fitting the shoes to your drum, the result can be what you have in your situation. Some big truck places still do it. DD
First, do you know your drum ID? New they are 12.00. The factory recommended max. is 12.090. You can get by with a bit bigger - but not much. I'd check that first. Also, some Ford backing plates had an eccentric adjuster for the shoes - but I don't know if your Zepher backing plates do, or not. If you do get to the point of needing to re-radius the shoes, you'll need to know the drum ID anyway, so as I said - start there.
i would pull one of your brake shoes and hold it inside your drum so you can have a look at it, a small flashlight shining behind the shoe will help, i have used my belt grinder to fit shoes to drums.
If the drum inner diameter checks out to be useable, you could rig up a fixture to 'radius' your shoes on a disc/belt sander.......the disc part as it is rigid and would likely provide a true(r) surface. It would require an adjustable pivot point (for correct radius) and a bracket or arms to bolt to the shoe reinforcing web. Of course it also has to be perpendicular to the sanding disc. Sounds more complicated than I think it would be...........besides would be fun and give a sense of accomplishment! Ray
Yep, did that and tried sanding the shoes down a bit, but its a hard job by eye. It did help a little though.
I don't have an big enough accurate measuring device, but I suspect I'm over the .090. Reckon about .120
Get yourself a magic marker and draw some lines the length of the shoes. Put the drums on and take it for a ride. Cycle the brakes a few dozen times take it home and take a look at the shoes. Get a rubber sanding block with the appropriate grit paper, and a good respirator. Sand where necessary and repeat the process. It doesn't have to be perfect but 75% would be good. The rest will wear itself in.
quick fix,grind the lower 1" of the shoe at a angle. The bottom is hitting and your not getting full contact. Common problem with early repop backing plates. believe me I know.It will make a HUGE difference (hand grinder and 80 grit works fine)
I bought an "in work" rolling chassis & body almost totally repro parts, including Lincoln backing plates. Had an issue with the drums contacting the shoes only on the lower end like that. When I checked the shoe fit in drum, that fit was within reason with the shoe held against the drum by hand. The backing plate anchor bolts were holding the shoes down too low. Fixed by removing anchor bolts, opening upper side of hole with die grinder. Then I put it all back together with the anchor bolt nut loose. Then I tightened the brake adjuster till it locked things up tight, tightened anchor bolt with the shoes now held in position by being jammed out against the drum by the adjuster. The brake shoes now contact drums full length since their arc is concentric with the ID of the drum. Feels much better in adjustment, etc. Haven't cmpleted car far enough to drive yet but I believe the problem is fixed! Dave
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