Drum brakes worn unevenly

[TimmyG]

I only remember working on drum brakes maybe once before... maybe twice. Could use some help please.

 

Inspected one of the rear drum brakes tonight (driver's side). Didn't have time for passenger yet. 

 

Driver's drum was very hard to remove even with two bolts thread in to push it off. It kept popping loudly as it began to come off so I released the adjuster star some. I think it was too tight. 

 

Brake shoes were worn slightly unevenly left vs right shoe. Also worn unevenly top vs bottom of each shoe, especially the rear shoe. Thinnest part was about 1/16 in. Looks like she needs new shoes. Why are they worn so unevenly?

 

Kind of hard to photograph. 

 

 

 

 

Also, when I put the drum back on it and tried to adjust the shoes... the drum kept lightly catching at the top of every revolution. Must be out of round? 

 

I will look at the passenger side tomorrow. 

 

 

 

[datzenmike]

When adjusting, pump the brakes every try. This will center the adjuster.

 

The adjuster at the bottom has to be free to move side to side to center itself as the shoes wear down.

 

Anything (but the shoe surfaces) that rub metal to metal should have a small dab of brake grease.

 

Always good idea to loosen off the e-brake cables when attempting to remove the drums and back the adjuster off. For this you have to poke the self adjuster away from the backing plate before turning the start wheel. 

 

 

 

[TimmyG]

Good tips. Thank you. Any idea why the shoes wore unevenly? Adjuster too tight causing the bottom of shoes to wear more? When I bought the truck recently the e brake adjustment was so loose it wouldn't hold the truck at all, so that wasn't dragging. 

[TimmyG]

Also, are they self adjusting? Not familiar with how it works. When the shoe pushes out farther due to wear does it spin to the next tooth on the adjuster and catch?

[datzenmike]

They are self adjusting. There is a ratchet mechanism on the star wheel on the adjuster. Only IF, there is excessive brake shoe movement will it move down a notch and turn the wheel. 

[banzai510(hainz)]

drums will always have a slight drag at one spot as drums are not precise Long as it don't get hot. On my Jeep I had out of round drums(NEW) had them turned then they was ok

Brake drums are not a perfect system. So I don't think they will be perfect wear pattern

 

I would lube up the adjuster(tube) if possible When I just did my 521 I used PB plaster then very antisieze on the threads. Over time brake dust and maybe a leaky seal will make the adjuster hard to turn

 

that rusty part where the drums meet I put antisieze on there. It helps keep it from rusting and sticking to the flange

Edited September 30, 2019 by banzai510(hainz)

[TimmyG]

Thank you, @banzai510(hainz)

[captain720]

I made a little drum brake video for our 720s in case anyone has trouble with them in the future.