Huh? broken brake shoes

[bk95td]

I went to put the rear drive shaft backon my 94 k2500[599 project] truck and couldn't turn the rear wheels to get the yoke to line up with the u-joint.:nonod: Ok ,truck has not been driven in over 7 years,so there probly is rust on the drums binding the shoes. I loosened the adjusters on both rear wheels and got the driveshaft in.:thumbsup:
Since I really don't know the history of this truck I thought I should check the rear brakes and clean the rust off the drums. When i pulled the axle out and the drum off the driver's side both shoes had cracks in the linings
There was no rust on the shoe surface of the drum. There was no groves in the drum either. The drums appear to be originals by the amount of rust on the outside. The truck has 200,000miles on it. The brake shoes are more than half of original thickness and aren't the originals.
The only thing I can think might cause this is maybe the drums are worn out so the shoes aren't the right radius or They were just really crappy shoes.
Has anyone else had this happen? Any other ideas what could cause this?
I hate to replace drums that look this good inside but don't want the same thing to happen again. I'm a little lost here. I've never seen this before.
Thanks for any help or insight , Barry

 

[Big T]

Your drums have chipped lips in the right photo. By all the rust, I assume you live in the snow belt. Brake shoes probably cracked sitting there in low temps.

 

[bk95td]

The missing pieces are milled to balance the drum not broken off. Never thought of the drums shrinking from cold temps. They were adjusted up pretty tight.

 

[ak diesel driver]

IIRC treegump had broken shoes on his recently

 

[WarWagon]

Crack also tightened things up. Someone may have left the parking brake on and drove it. Never seen a crack that bad, but, have seen cracked linings. Usually from oil or brake fluid in the lining or overheating.

I would suspect oil or brake fluid and rebuild/replace both wheel cylinders and replace diff oil seals. Problem may have been fixed without shoe replacement.

I have personally warped hot drums by putting on the parking brake after towing on a 2005 1/2 ton GMC, factory cheap drums without cooling fins...

 

[bk95td]

No signs of oil contamination or overheating. Backing plate is dry. Same with the drum.

 

[Crankme69]

WOW BK guess I better give mine a look see thanks for sharing!

 

[bison]

Any play on the rivets?
I would turn the drums though.

 

[Crankme69]

Maybe you could just set the drums on the axle & check em for runout like I check the rotors? If them drums are true...I'd run em.

 

[bk95td]

I got the other side apart today. No broken shoes there,just gear oil. Drums have very slight grooves. I also found brand new brake shoes for one side in my brake parts area:thumbsup:The brake shoes were from my 77 gmc c3500. How's that for interchangeable:thumbsup:h. Looks like I can get by cheap this time with only buying oil seals and wheel cylinders. The springs must have been replaced with the last shoes because the paint is still shiny on them. Wheel cylinders are only $10 each, so I might as well replace them as long as it's apart. Next rear brake job will be a $300+one.
The gear oil on the other side shoes would make that side lock and possibly shock load the side that broke. That's my newest theory anyhow. Still puzzleing

 

[bison]

IMO more like the dry side took the brunt of the braking,the other side would have slipped on the oil.

 

[buddy]

Neither side would do very well if one side was leaking. I believe our master cylinder splits front to back to isolate the discs from the drums. So if there is a leak on either drum neither would do very well.

Same thing happened to me. I had one badly leaking drum clylinder and both sides looked like there was no use of the shoes. Good thing the front discs do a great job. I replaced both cylinders. Just make sure you get the right size cylinder, my 1500 seemed to have a larger dimater piston than the bigger trucks. They are cheap though, thats good.

Then pushed out most of the old fluid and poured in new and bled all brake lines, which is like a 2 man job. Of course want to make sure you never completly empty the master cylinder of fluid.

 

[bk95td]

IMO more like the dry side took the brunt of the braking,the other side would have slipped on the oil.

That's what you would think, but it is the opposite. Oil on brake shoes will make them grab better.They grab too good and lock up before the other brakes really start to grab.

 

[WarWagon]

I would not use used shoes.
I put a new set of drums on my 1/2 ton Yukon without changing the shoes.

Couple thousand miles later they sounded like a big truck stopping with the sequel.

Turns out the smaller diameter of the new drums contacted only part of the shoes that were broken in on the larger drum diameter. Yeah small difference made it work right and quietly or not. New shoes fixed the noise problem without turning the 'new' drums.

 

[bk95td]

I would not use used shoes.
I put a new set of drums on my 1/2 ton Yukon without changing the shoes.

Couple thousand miles later they sounded like a big truck stopping with the sequel.

Turns out the smaller diameter of the new drums contacted only part of the shoes that were broken in on the larger drum diameter. Yeah small difference made it work right and quietly or not. New shoes fixed the noise problem without turning the 'new' drums.

I've had good luck degreasing the shoes with brake cleaner. The broken side will be replaced with the new pair from the 77 1ton. I've used way worse drums than these with no problems.
The GM service manual says you can just replace pads or shoes without turning them as long as they aren't grooved bad. Brake mfg. say the should be turned or replaced, but they are in the business of selling parts.

 

[dangerousdave]

I've had cracked shoes many times; HEAT, pressure, and bad materials. They used to arch shoes to match the drums, no mo. Cheap, cheapo parts. Overloaded through the desert and mountains don't help none niether!

 

[tanman_2006]

My 305 Gasser has had cracked shoes since I got it 6 years/ 110,000 miles ago, no problems but I wouldn't advise it. I'm in college and dont drive the truck anymore so I can't justify fixing it. Mine weren't cracked that bad though.

 

[treegump]

IIRC treegump had broken shoes on his recently

yea, both sides were cracked - and on the passenger side, the top piece was missing (there was a tiny part left as it had been ground down to look like a bolt head). I had accidently left my p-brake on and also for the last 10k miles or so my e-brake had been sticking. I loosened the driver's side e-brake mechanism as far as it'd go and disconnected my e-brake. I'll fix that when I've got some more time.

On one side (I don't think its on both sides) the drum lip is chipped too, but that's because I used a hammer to try and loosen it up when I first got the truck. Since then, I loosen the adjustment all the way and rotate/slide it off.