Getting the most out of Drum Brakes

2bav8 said:

crapola
Spend $500 and get er done!
Front drum brakes SUCK! :Track:

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$500 bucks? How, with a trip to the junkyard? Most new kits I see are $1000 for just the front brakes.

Here is something that will be tough to find but will improve your drum brake performance. Try and locate and older auto repair shop, one that has been in business for decades, ask them if they still have the machine required to match the brake shoes to the drum.

While a 10" drum uses 10" shoes performance is best when the friction material is cut to exactly match the arc of the surface inside the drum. A drum that has been cut is no longer a 10" drum, so a new 10" shoe does not make full contact along the length of the shoe.

If you doubt the need for this, install your new shoes, have someone lightly push on the brake pedal while you rotate the drum. Remove the drum and look at the marks on the shoe where it rode against the drum.

This process has disappeared due to asbestos concerns, but someone may have thew machine in the rear of the shop. Maybe they can hook you up.

$500 bucks? How, with a trip to the junkyard? Most new kits I see are $1000 for just the front brakes.

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http://www.geocities.com/2bav8/granada.html
I spent $100 for Granada spindles at the salvage yard and the rest rebuilding the brakes using new parts.

68conv4sp said:

66 Hertz Clone, The most valuable comments related to cutting the drums to fit the shoes - you are right that old school speed books say this is a must. Also, Historic Mustang, your comments are smart in that you understand my goal - maximize what I have for minimal cost. Good fluid, balanced pressures to match lock up rates, and cooling as possible. Mustang Dave, thanks for the info on the different drum shoe/drum widths. I'll see what is out there for next to 0 cost. These are the kinds of thoughtful replys that make this site valuable and fun. Tom

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A few more suggestions (kind of a slow day at work). Between sessions if you have time and enough help get the car jacked up and the wheels off - this will help the braking system cool quicker. Stay away from using paint on the drums, it just holds in the heat. If you have the front rubber hoses I have actually seen small hose clamps applied to the hose (this application had the ribs and the clamps were between the ribs) to help with loss of stiffness. Same thing on rear rubber hose from the rear end.

The biggest thing you can do is the bleeding between each session - yes it is a pain but pays big benefits.

HistoricMustang
www.historicmustang.com

66HertzClone said:

Here is something that will be tough to find but will improve your drum brake performance. Try and locate and older auto repair shop, one that has been in business for decades, ask them if they still have the machine required to match the brake shoes to the drum.

While a 10" drum uses 10" shoes performance is best when the friction material is cut to exactly match the arc of the surface inside the drum. A drum that has been cut is no longer a 10" drum, so a new 10" shoe does not make full contact along the length of the shoe.

If you doubt the need for this, install your new shoes, have someone lightly push on the brake pedal while you rotate the drum. Remove the drum and look at the marks on the shoe where it rode against the drum.

This process has disappeared due to asbestos concerns, but someone may have thew machine in the rear of the shop. Maybe they can hook you up.

Click to expand...

actually it's not as hard to find as you think. find a big truck repair shop most of them still match the shoes to the drums and can still car brakes as well, if they don't they know someone who can.

also don't discount the cross drilling of the drums, this is very effective on drum brakes, even more so than on disc brakes. in fact the cross drilling process was originally developed for 50's nascar racers and adapted to disc brakes some years later. i would say that dollar for dollar drilling the drums IS THE BEST upgrade you do, it not only helps to disipate the heat but also allows any water that gets in to have a way back out as well. this is actually a pretty good do it yourself project as well as it is not hard to do, you just have to make sure you have even distances between all the holes. to do this all you need to do is define where you are going to drill the holes, again paying close attention to the distances, you will want to out them at an angle going from outside front to inside rear about 3 holes per line of holes. just drill them from the outside of the drum. also wouldn't hurt to drill some holes in your backing plate where your ducts will be.

here is a link showing how it's done

http://www.chtopping.com/CustomRod4/

http://www.chtopping.com/CustomRod4/examples1/examples1.html

here is another page that shows how to do it and the details are a little clearer

http://www.tffn.net/drilldrum.html

I drove drum brake V8 Mustangs all through high school and college (more than 80K miles). I did everything I could to optimize the brakes - big finned drums (can't remember what kind of car they came from), constantly adjusted them, new wheel cylinders, etc. Granted I did not have state-of-the-art shoes but the rest was optimized as well as possible.

To put it bluntly - they sucked. Forget panic stopping from 80 mph - they would just fade away. I mean that my foot is still on the brake pedal and the pedal is not on the floor- I'm just not slowing down any more. Not to mention that sometimes they pulled to the right, sometimes they pulled to the left, sometimes they didn't pull at all.

I would NEVER drive a drum brake car in Houston or any other high traffic area. I shudder at the thought of getting out on a race track with them.

As for drilling them - let's take this 35-year-old drum that has suffered God-knows-what kind of abuse and start punching holes in it. No thanks.

And if you are talking about buying new drums and new drum brake parts and new shoes and paying labor costs to have the shoes fitted to the drums - well, pretty soon you will have spent as much money as if you had gone the disk route. And you will still have substandard brakes.

I just don't see the point.