78 CJ5 rear drum size

[Agent915]

There should be very, very little, if any. If you've got noticeable in/out movement, you've got a problem somewhere.

Thanks Hack,

I'll check it first thing Saturday morning, with fingers crossed!

Danny

 

[Agent915]

There should be very, very little, if any. If you've got noticeable in/out movement, you've got a problem somewhere.

Ok, here's the latest. Rains gone, Suns out, so I got the CJ up on some stands. Before pulling the rear wheels I gave each one the push/pull test and everything seemed fine. The drums are 11" (stamped) and they fit over the backing plate with very little space between the plate and drums. I did not see brake shoes protruding beyond the drums, or how it would even be possible. One thing did catch my attention, the drums extend beyond the plate maybe a 1/2" to 3/4". Not sure if that's normal or not. I didn't pull the drums to check any further because I don't know enough about drum brakes to diagnose the problem if I saw it. I contacted a mechanic to address the brake situation. Is it possible that the shoes are too wide and making contact with the inside face of the drums and that's the source of the noise? I feel like I'm throwing stuff against the wall seeing what will stick!! SO FRUSTRATING

Danny

 

[Agent915]

Bump

 

[Hedgehog]

Here's a suggestion and possible simple cure to your problem. Drum brakes are designed to self adjust when you are going backwards an apply the brakes. Try backing up briskly and hitting the brakes, do it a few times. Then road test to see if the noise goes away.

There is also another possibility. The backing plate has bumps or bumpers to keep the brake shoes aligned. Over the years they can build a ridge that the shoes can catch on. Bumping the brakes can pop'em loose. If this is the problem the backing bumps can be ground smooth. If bad enough a welder can add material (metal) for a new wear surface. My CJ had this issue, occasionally the front drum brakes became extremely grabby, pulling the CJ hard to the left. The back up and stab the brakes would cure the problem for long periods of time. I was going to grind and possibly weld on new surface material, but ended up upgrading to disk brakes.

 

[Agent915]

Thanks Hedge, I'll give it a shot this weekend! You wouldn't happen to have a picture of the "bumps" you were referring to would you?

Danny

 

[Hedgehog]

Nope, they are more or less buried under the brake mechanisms and are difficult to see without taking the whole brake apart. If you are in there it's easy to see them, there's no real science to them. I think there are 4 of them, two on each brake shoe. All they do is hole the brake out towards the drum. Remember the drum rotates, the rest of the system pretty much sits and does nothing until the brakes is applied. Even then there is very little real movement of the shoes to make contact with the drums.

 

[Agent915]

Hopefully I can open them up this weekend and see whats going on. I'll snap some pics. Maybe you guys can see something I don't and help me solve this issue!

Danny

 

[Hedgehog]

Try the backing up brake thing first to see if there is any change.

 

[Agent915]

Try the backing up brake thing first to see if there is any change.

Will do! Thanks!

Danny

 

[Hedgehog]

I know the whole idea seems far to simple and likely it is to simple, but you never know until you try. The brake shoes might just need to be reset.