Have you ever seen brake shoes wear like this? (1 Viewer)

[edwjmcgrath]

PO claimed a recent brake job but they weren't working quite right so I thought I'd check it out.
I pulled the rear drums and the first thing that I noticed is that the shoes are only touching the drum on about 30% of the shoe. (Dark part is normal wear, light part is original unworn shoe.) It looks like the shoe diameter must be larger than the drum diameter. It's that way on all 4 shoes. I've driven like this for a while so they aren't just breaking in. Two of the four cylinders are leaking, one leaking rust, and another has a cracked adjuster so I've pulled everything and have all new cylinders, shoes, and flex hose on their way. I'm just curious what would cause this wear pattern. I wonder if these shoes are for a different vehicle or model.

Also showing a closeup of the relining job on the shoes showing glue and pop rivet. Not exactly top notch...

 

[amaurer]

Looks like the wrong shoes.

 

[fieldsken1]

looks like the shoes were not arched to fit the drum

 

[edwjmcgrath]

We'll see better on Tues when the new shoes arrive.

 

[skidplate]

I'm wondering if the drum has been turned so many times that it now is too large for the brake pads? I have to honestly say, my brake guy always turns my drums and never asks how often it's been done, or measures the drum thickness.

 

[jp_waltz]

I'm wondering if the drum has been turned so many times that it now is too large for the brake pads? I have to honestly say, my brake guy always turns my drums and never asks how often it's been done, or measures the drum thickness.

x2. I had my front drums turned a couple months ago and it seemed like I lost some braking power after. I pulled the drums off and they looked just like yours.

 

[Mr. Toad]

I'm wondering if the drum has been turned so many times that it now is too large for the brake pads? I have to honestly say, my brake guy always turns my drums and never asks how often it's been done, or measures the drum thickness.

x2. I had my front drums turned a couple months ago and it seemed like I lost some braking power after. I pulled the drums off and they looked just like yours.

Negative. If the drum diameter were too large, the pad would show the opposite wear pattern.

OP: Don't forget to follow-up in this thread when you get the new shoes.

 

[peesalot]

FWIW my 70 fj40 had the same wear pattern on the shoes after I did the brakes, you can have the shoes arced to closer match the drum but IMO , run the new stuff for awhile, I bet you get same wear pattern.

 

[bj40green]

The shoes are too big for the drum.

Rudi

 

[Pighead]

Could it be that they were just never adjusted tight enough?

 

[JohnnyC]

how long have you had the cruiser? did you ever adjust the drums? if you drive alot...they should be adjusted every 3 months or so...they are not self adjusting

 

[edwjmcgrath]

I don't drive a ton-these shoes might have 1000 miles on them. They were adjusted a few hundred miles ago but they didn't stay solid for very long-probably because they were wearing more quickly at the ends. When I pulled the drums, they came off easier than I expected-it was definitely time to adjust again.

I think that the arcing theory is probably right. New shoes need to be larger than a new drum because they need to be made big enough to accommodate drums that have been turned a few times. So you either need to wear them in or have them arced.

I'm going to change the shoes since they were wet with brake fluid so I'm probably going to go through this again with the new shoes. At least they'll be easy to adjust with the new cylinders.

 

[My wife said no FJ!]

Did you put 4 new drums on your purchase list?

 

[edwjmcgrath]

Did you put 4 new drums on your purchase list?

I'm only doing the rears right now. I may do a disk conversion in the future.
The rear drums are fine. They measure 11.43 with a maximum spec of 11.7 and there are no grooves to speak of. They were the only good news.

 

[edwjmcgrath]

Mystery solved.
Here are the old shoes (top) and the new shoes (bottom). I lined the shoes up at the ends. You can see the gap in the middle. The old shoes are maybe 1/8" away from the drum at the middle of the shoe, so the middle of the shoe doesn't wear away. Just a poor relining job. They probably would have eventually worn in.

New shoes fit almost perfectly to the shape of the drum. No arc'ing required.
Thanks all. Maybe you can help me out with my new bleeding problem... to follow in another post.

 

[Pin_Head]

The shoes just weren't arced properly as mentioned previously above.

The machine shop does that when they turn your drums. Even if you don't turn the drums, you still need to arc the shoes. You can do it manually with a shading block, but it takes more time. Maybe not as long as running to the machine shop with your drums and shoes. To manually check the arc, scribble some chalk inside the drum and wipe the shoe across the surface and look for full contact. Some shoes fit better out of the box than others, but they should all be properly arced.

 

[numby]

Some shoes fit better out of the box than others, but they should all be properly arced.

Wow! I never heard that before. I learn new stuff here all the time.

 

[JohnnyC]

do you know where the old shoes were from? so others can avoid the same issue

where did you get the new ones...when i had drums i got mine from SOR and MAF...was always happy with them

 

[cuencanolenny]

I'm only doing the rears right now. I may do a disk conversion in the future.
The rear drums are fine. They measure 11.43 with a maximum spec of 11.7 and there are no grooves to speak of. They were the only good news.

No, your numbers are wrong as you're indicating a diameter range of .270. The spec is 290-292mm, .08 from new to maximum.

 

[Casey E]

This thread is 7 years old bat man.