Tuesday, July 29, 2008

Six Months of Brakes

Once the truck was up on blocks, I decided to do the brakes, starting with the left rear. I had always suspected foul play in this one, as a previous post had mentioned, because the truck always used to pull to the right when the brakes were applied. The greater the pressure applied on the brakes, the greater the pull. Slamming on the brakes once had actually caused my truck to lurch off the road on two wheels once. Ah, memories.

I'd post a picture of the brake drum of the offending wheel, but I gave it to a scrap guy before I thought of that. I'll attempt to describe to you this surprising feat of things wearing out and breaking. Imagine a brake drum as a short, heavy pot. This pot slides over the rest of the brake mechanism, bottom side away from the car. The wheel then mounts up against the bottom of this pot. Get the picture? The car stops when the brake mechanism inside the pot (or drum) applies pressure to the inner wall of the rim of the drum. The friction is what slows the car.

Now imagine what it would look like if the sides of the pot were to break loose from the bottom. You would only have the flat bottom and the ring like piece that was the sides. Now imagine this side piece cracked across in one place, to form a tightly closed C shape. That's pretty much what happened. This C shaped ring was forced by the brake mechanism to open up (making the crack wider) until it was bigger around than the flat bottom it broke off from. It then dropped down over that flat bottom until it was no longer in contact with the mechanism, and then it clamped down tightly as the C tried to close back into a ring.

The end result was a very odd looking brake drum. It took me a while to figure out why it looked like it did. This drum was removed and disposed of. I'd like to backtrack for a moment to my first experience with drum brakes. The left rear brake on my Camaro was leaking fluid some years ago. My dad, with his years of experience with cars, took one look at it, and then proceeded to remove all of the components of the mechanism with surprising speed. I don't remember what was said at this point, but whatever it was irritated my father to the point where he went back inside, leaving me with a pile of levers and springs and things and no clue how to assemble them, since I wasn't the one that took it apart. Between my Haynes manual, Nick's dad, and taking the other wheel off to look, I learned the hard way how they go together.

When I pulled the rear brake drums off the truck I was surprised to see that, despite a 25 year difference between the cars, the brakes were virtually identical. I had both drums off at the same time, experience, and no book. I did manage to remove all the hardware and replace it all, replacing the old springs and, well, a piece I lost. The springs and levers and things and brake shoes (the part that rubs on the inside of the drum) all go on at the same time.

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