A lot about brakes

[cj847]

I wanted to post stuff about brakes that I hope can help some folks. Feel free to correct, criticize, clarify add to, ect. I will make several posts as I have time.

DRUM BRAKES.
I find that drum brakes are hated by most people because they are not understood. At the likely chance of showing what I don’t understand, I will try to explain. Also, the information on the internet is sketchy, confusing and disjointed at best. This information is specific to the brakes on 67-72 truck. While most of it can be applied to any drum brake, some cannot.
The first point of confusion is which pad goes where. These shoes are called primary and secondary. The primary shoes has less friction material and goes to the front while the secondary shoe has more friction material and goes to the rear of the vehicle (this is the last time I will use those terms as I find they add confusion). While the brakes will perform whether the long pad is in the front or the rear, the long pad goes to the rear of the vehicle. And here is why:

The pin in the circle is the only thing that stops your truck. If it was not there the shoes would stick to the drum and spin along with them or at least blow out the wheel cylinder. (Like most things automotive, one bolt or pin is all that separates you from almost certain death). When the brakes are applied, the wheel cylinder expands and the shoes touch the drum. The rear shoe is forced against the pin giving it ultimate stopping power. The front shoe is working as well but only with the force applied by the wheel cyl.

The next point is all those springs and holders. The main thing here is to have the right tools and to take pictures before disassembly. Caution on pictures- most drum brakes I have seen have at least one mistake by the last person who worked on it. For example, my truck had the shoes on backward. Be careful as several parts are side specific. You can do a brake job with screwdrivers and pliers, and you will hate it. Even with the right tools it is frequently a problem. Here are the main tools:

https://www.harborfreight.com/drum-b...ece-63640.html

The self-adjuster. This ‘gadgetry” adjusts the brakes when they are applied in reverse. Think about the above example of the rear shoe being crammed into the pin in reverse. Now the front shoe is crammed into the pin. But, more importantly, any free space between the drums and the shoes opens up at the top of the rear shoe. When there is enough space the “gadgetry” acts on the self-adjuster to expand the distance between the shoes at the bottom. This is why when backing out of your driveway, you should come to a stop with your brake instead of just coasting and shifting into drive. This will keep your drum brakes well adjusted.
PS> yes I know that the diamond shaped washer is missing in the picture. (see green circle)

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