A ??? for those with a 71-72 rear drums

[lts70]

On my 70’s back drums I have an oval slot to adjust the brake adjuster. I am switching to 72 drums but the ones I got do not have an oval slot. Would this be a stamping defect or is that the way they came in 72? If so how do you adjust them and back them off when changing shoes? Thanks.

[tgriffin27]

What you have is probably aftermarket drums that didn't come with the slot. They are not hard that much harder to adjust you just have to take the drum off and adjust them a little at a time. Put the drum back on your brakes and spin them by hand till you think you have them just right. Hope this helps.

[lts70]

Would it be a good idea to drill an access hole? I could do it in the back plate like newer cars. Maybe drill two holes, one to adjust and one to hold the little plate up. Or I could drill one into the drum. I am not worried about getting them adjusted initially. I am worried about getting them off later with out the ability to back the shoes off. What would you guys do?

[nightmare]

I wouldn't drill into the drum. they are counterbalanced to reduce the vibration. any removal of material in one centralized location will throw that off. I would drill the back side of the plate, making an oval to be able to adjust the adjuster.

[lts70]

I guess I will drill some holes in the backing plate and seal them up with some silicone. Then when I need to adjust or back them off I can just cut out the plugs and do so.

Has any one done had to deal with this on there own truck?

[nightmare]

Not personally, but i don't think that you even have to plug them back up.

[hilandr452]

Drill the holes and buy the little plugs at a parts house they sell them aftermarket. (in the back plate, not the drum)

[lts70]

I ended up drilling one small hole about 2 to 3 inches up from the bottom to get to the plate that keeps the adjuster tight. And I drilled another oblong hole at the bottom that is the same size as the original slotted hole in the drum. I would have just drilled the lower hole but it was not possible to reach the plate and the adjuster from the same location. I got the little rubber grommets that are made to plug the adjuster hole and will be using a little silicon to block off the upper hole if I can not find a couple small round grommets that will work. I will take some pictures if anyone has the same problem and needs a reference.

[special-K]

Are you talking about the backing plate or the drum?

[lts70]

The holes I drilled are in the backing plate.

[tgriffin27]

So how did the brake adjustment go did you find anything to seal the holes up with?

[72armyswbtruck]

Aren't those rear brakes suppose to be self adjusting.
I always thought that all you needed to do was drive in reverse and they self tensioned.

[lts70]

Originally Posted by tgriffin27

So how did the brake adjustment go did you find anything to seal the holes up with?

It went great, thanks. I used the adjustment hole grommets for the oblong hole and a dab of silicon for the small hole for now.

Originally Posted by 72armyswbtruck

Aren't those rear brakes suppose to be self adjusting.
I always thought that all you needed to do was drive in reverse and they self tensioned.

When I had Drum brakes in the front I used that backing up trick as well. When she would start to pull one way or the other I would find an empty parking lot and slam on the brakes in reverse, straightened her out every time. I wanted the manual adjustment for when I need to take off the drums to do a bake job or just check things out. It is nice to be able to back of the pressure of the pads on the drum, especially if they have seated in very far.