Is this how 71 rear drums should look?

[GregoryB]

Well shoot. I'm going to start cleaning this up for a full rebuild. This looks like some heavy grease build up, should I be checking other things when I take this all apart?

 

[Rzeppa]

No. All that grease had to come from somewhere, I'd say most likely you have worn out axle seals and that's 90wt mixed with dust and dirt.

First, check the 90wt diff level by taking the fill plug off and sticking your finger in. It should be up to the bottom of the fill plug hole. I's speculate it's probably a lot lower than that.

In order to change out your rear axle seals you're going to have to pull the axles, which will involve removing the cross shaft from the carrier so you can get the c-clips out.

Do you have a FSM or at least a Haynes?

 

[Rzeppa]

I'm not sure what you mean by "full rebuild"? Do the rear brakes operate at all? I think it's unlikely that the source of that gunk is brake fluid, if it was leaking that bad you'd be losing fluid from the reservoir pretty fast. I had a leaking wheel cylinder in my FJ45 recently and it was pretty obvious; I ended up replacing all 4 cylinders and shoes.

Once you have it all cleaned up, you may just need new shoes and maybe turn the drums, as far as how much brake work you need. But you'll need to fix the source of all that gunk, which as I wrote above, is likely worn axle seals. Worst case would be the reason the seals are shot is that the rear axle bearings are shot. They're a PITA to remove as the outer races are pressed into the axle housing.

 

[Rzeppa]

Here's a write up I did on Land Cruiser drum brakes. It's old, but so are our rigs, and it's still applicable.

 

[GregoryB]

I'm not sure what you mean by "full rebuild"? Do the rear brakes operate at all? I think it's unlikely that the source of that gunk is brake fluid, if it was leaking that bad you'd be losing fluid from the reservoir pretty fast. I had a leaking wheel cylinder in my FJ45 recently and it was pretty obvious; I ended up replacing all 4 cylinders and shoes.

Once you have it all cleaned up, you may just need new shoes and maybe turn the drums, as far as how much brake work you need. But you'll need to fix the source of all that gunk, which as I wrote above, is likely worn axle seals. Worst case would be the reason the seals are shot is that the rear axle bearings are shot. They're a PITA to remove as the outer races are pressed into the axle housing.

Thanks. I meant rebuilding the brake components, but the gunk looks heavier than brake fluid mixed with normal dirt and brake dust. Rear brakes were working normally from what I understand, but it had a serious leak and now the pedal pressure is gone, that's why I pulled this apart to take a look.

 

[Rzeppa]

The only brake components that can be "rebuilt" are the wheel cylinders and master cylinder. In my experience it's best to replace with new than try to rebuild them. But there's a good chance there's nothing wrong with them and your real issue is your axle seals. Are both sides that bad or just the right side?

 

[GregoryB]

Passenger side is not as bad

 

[RDub]

Gear oil stinks. Bad. Maybe take a close sniff of that gunk and see how it smells. If it’s heavily soaked with diff fluid you’ll probably smell it.

 

[GregoryB]

When I pulled the fill plug, oil seeped out slowly. I tried smelling some fresh gear oil, it was noticeably stinky. I smelled my brake gunk and surrounding area, not as smelly, but not sure I trust my nose reading.