Drum brakes : Braking force multiplied?


#21

I uploaded the drum-brake photo which appears at the bottom of the top post in this thread. You aren’t seeing it there? hmmm … must be some kind of technical difficulty. In that photo – which is presumably a Mopar configuration, but I chose if b/c it is very similar configuration to my Ford truck – there’s a single wheel cylinder at the top, just below an immovable anchor which the top of both shoes abut. At the bottom there’s no anchor, the adjuster there effectively connects the bottom of the two shoes. The two shoes are about the same size but the linings are different. The rear shoe has a significantly longer strip of friction material than the front shoe.


#22

Chrysler discontinued the double leading shoe brake design in the 60s. Power brakes and the improvements in the single, double ended design mad the expense of the two wheel cylinder and driveshaft emergency brake unnecessary.


#23

Here’s my truck’s drum brake configuration. Given the emergency brake lever position behind the right shoe, I think this is the driver’s side rear wheel. The front of the truck is to the left. Note the rear shoe (right) has more lining material than the front (left), which is consistent w/the rear shoe getting extra force from the front shoe pushing on it during braking.

One question for the experts here about ford drum brakes. See that red arrow at the bottom left right? It’s pointing to the hole where the brake adjuster lever pivots on the rear drum. How do you folks remove the adjuster lever when servicing ford drum brakes? The instruction manual I have says to loosen the adjuster screw all the way, then pull on the adjuster pivot nut, back and down, which supposedly reduces the tension in the adjuster cable & allows the lever to be removed from that pivot hole. That’s not how I do it. I just lift the adjuster cable up and over the guide (upper right). It seems like a much simpler method. Is there a reason why the instructions say to monkey with the adjuster to remove the adjuster lever?

ford_drum_brakes


#24

Like they say, there’s more than one way to skin a cat. I recall removing the shoe return springs on the top and that freed the adjuster cable guide which allowed the adjuster lever, spring and cable to fall free.


#25

That makes a lot more sense than the way the manual instructions say. Those springs have to be removed anyway.


#26

I remove the blue spring in the picture first. I hold the self adjuster lever in place with my right thumb, grab the end of the spring with side cutters with my left hand, and extend the spring enough to unhook it.


#27

That’s how I do it too.

It was nice of them to color code the springs for you.


#28

Here’s what my Haynes manual says. Step 3 makes no sense to me as written. Think it might just be an editing error?

Step

  1. Remove drum
  2. Put a clamp on the wheel cylinder
  3. Move the outboard side of the adjusting screw back and up off the pivot nut as far as possible. It will now be possible to pivot the hook from the rear brake shoe.
  4. Remove adjusting spring, etc etc

#29

Some skin from the ankle up while others from the ears down.


#30

What do you think they mean by “outboard side of the adjusting nut”? I can’t decide which is the inboard side, and which is the outboard side. Even if I wanted to do it that way, I’d have no idea what to do.