"Lumpy" Rear Brakes?

[wired1000]

I have a weird issue with my M1009. It has to do with the rear brakes (95% sure).

So, when braking, I can feel a sort of "lumpiness".... that is to say, the brakes are not totally even. If I press the brake, there is a rhythmic pulsing to how well the brakes work. I think something is out of balance.

Why do I think it's the rear brakes? Well... I just replaced the front brake pads and all looked well up there. About 9 months ago I replaced the entire rear axle with a brand new one, drum-to-drum, from a fellow SS member. After the axle replacement, I noticed it would make these terrible shrieking-grinding-metal sounds when I drove in reverse (only in reverse). The mechanic who replaced the axle suggested that I get up to about 5-10mph in reverse, then SLAM on the brakes, which would realign the shoes. After doing this a few times, the shrieking subsided, but there is still a bit of squeeking that happens (still only in reverse).

However, this lumpy brakes issue seems to have gotten more noticeable over time. What does everybody suggest I do to 1) confirm its the rear brakes and 2) fix the problem?

The truck stops just fine, but I don't want to ruin anything.

 

[Ken_86gt]

You could lift the rear wheels off of the ground, rotate the wheels and check for nice and smooth rotation. Also, take the drums off and actually look at the brake shoes and the inside of the drum- try to identify a spot that looks like it may have gotten hot compared to the rest of the drum. Drums do warp on occasion and need to be re-ground or replaced. If you have dragging rear brakes or stuck brake due to hardware,a stuck wheel cylinder, or improperly adjusted it could cause this.

 

[porkysplace]

I have a weird issue with my M1009. It has to do with the rear brakes (95% sure).

So, when braking, I can feel a sort of "lumpiness".... that is to say, the brakes are not totally even. If I press the brake, there is a rhythmic pulsing to how well the brakes work. I think something is out of balance.

Why do I think it's the rear brakes? Well... I just replaced the front brake pads and all looked well up there. About 9 months ago I replaced the entire rear axle with a brand new one, drum-to-drum, from a fellow SS member. After the axle replacement, I noticed it would make these terrible shrieking-grinding-metal sounds when I drove in reverse (only in reverse). The mechanic who replaced the axle suggested that I get up to about 5-10mph in reverse, then SLAM on the brakes, which would realign the shoes. After doing this a few times, the shrieking subsided, but there is still a bit of squeeking that happens (still only in reverse).

However, this lumpy brakes issue seems to have gotten more noticeable over time. What does everybody suggest I do to 1) confirm its the rear brakes and 2) fix the problem?

The truck stops just fine, but I don't want to ruin anything.

When you " slam " on the brakes in reverse , it is supose to engage the self-adjusters , not re-aline the shoes . Did he take the drums off and inspect the brakes when he installed the axel ?
As stated above it could be rusted drums , sticking wheel cylinders , broken spring ect. , you really need to take it apart and inspect it . Also when it got new front pads did you turn the rotors ? they could be warped and if the rears are not properly working and adjusted ,it puts more stress on the front which drums the majority of the stopping to start with .

Edit ; Also did he use DOT 5 brake fluid or flush the entire system and clean residue of DOT 5 out and reinstall DOT 3 . You can't mix the 2 brake fluids .

 

[Recovry4x4]

More often than not a pulsating brake pedal is due to warped rotors or out of round drums. No amount of forum conjecture will replace a visual inspection.