Rear drums too tight

[gale]

The rear drums on my '67 C20 are too tight to roll. There is no slot in the backing plate for adjustment. Any suggestions on removal of the drums?

[68gmsee]

First, loosen the bleed valve to see if it's built up pressure. If that does it, you need to replace m.c. or rubber brake lines or look for other blockage. If that doesn't help follow read the following threads for some ideas: http://67-72chevytrucks.com/vboard/s...d.php?t=345368

http://67-72chevytrucks.com/vboard/s....php?p=4575234

[geezer#99]

Pull the wheel off. MIght be a slot on the face of the drum.
Whack the outside of the drum with a hammer to loosen it up. Gently though, not a 2 handed beating. LOL!!

[gale]

Originally Posted by 68gmsee

First, loosen the bleed valve to see if it's built up pressure. If that does it, you need to replace m.c. or rubber brake lines or look for other blockage.

I removed the brake lines altogether.

[gale]

Originally Posted by geezer#99

Pull the wheel off. MIght be a slot on the face of the drum.
Whack the outside of the drum with a hammer to loosen it up. Gently though, not a 2 handed beating. LOL!!

There are no slots or holes anywhere in the drum. This is a C20 and the drum is pretty heavy stuff even with a lot of rust pitting. I have whacked pretty good with a 4 lb. hammer. The wheels do turn but only with a lot of force, like a puller (come-a-long) wrapped around the tire.

There are dimples in the backing plates where an adjustment slot should be. They are difficult to get at and that's probably the reason for the bends in an adjustment tool.

The last resort will be to cut the drum with cutting torch or I have a power bandsaw.

[LONGHAIR]

Whoa, whoa....this is a C-20. As in full floater axle, the drums don't just slide off of the hub. You have to remove the axle and the spindle nuts first. Then the entire assembly come off together.
If it really is held-up by the shoes, the simplest trick is to cut the heads off of the retainers.....of course that means you have to replace them, but a new hardware kit is a good idea anyway.
The next problem you will probably run into is parts availability. If you have the HO-52 "corporate" axle, you may be entirely out of luck. Parts are hard to get for them.

Unfortunately, you may be looking at an axle swap just to do a brake job.
A Dana60 or later model 14 bolt will not only help as far as getting parts, but it opens up more gear ratio options too.

[gale]

Originally Posted by LONGHAIR

The next problem you will probably run into is parts availability. If you have the HO-52 "corporate" axle, you may be entirely out of luck. Parts are hard to get for them.

Unfortunately, you may be looking at an axle swap just to do a brake job.
A Dana60 or later model 14 bolt will not only help as far as getting parts, but it opens up more gear ratio options too.

My original plan was to just get it rolling by hand to move the chassis around while I work on the body.

What do I look for to find out which axle I have?

[heyjoe]

Pardon me if you know and have done this already.
You are aware that the drums are affixed to the hub by the pressed in wheel studs, and that the spindle nut holds the whole shebang on, and that the axles must be removed?
If you have done the above and the drum and hub still won't budge, maybe try grinding off the nail heads that affix the shoes to the backing plate. Maybe you could remove the wheel cylinder bolts. These 2 things may give the shoes enough wiggle room.

EDIT:
I see LONGHAIR beat me to the above!

Drums are available by Centric Brakes. There is a thread on here about one man's quest for the correct Eaton drums. Here's the link: http://67-72chevytrucks.com/vboard/s...d.php?t=443837

[heyjoe]

For info and pictures of the Eaton please refer to a how-to thread by COBALT

http://67-72chevytrucks.com/vboard/s...d.php?t=200268

[Stocker]

This doesn't help with your immediate problem, but to avoid it in the future.... After you manage to get everything apart, drill holes in the backing plates so you can access the adjuster spur wheels. Then put rubber plugs in the holes.

[gale]

Originally Posted by Stocker

This doesn't help with your immediate problem, but to avoid it in the future.... After you manage to get everything apart, drill holes in the backing plates so you can access the adjuster spur wheels. Then put rubber plugs in the holes.

Thanks. I thought of that and even tried to knock out the slotted dimple. I thought it might be almost punched through like an electrical box but it held up to a few good smacks and didn't move.

[gale]

Followup:
Got a drum off this afternoon and it looks pretty good. I'll take the other one off and see if my NAPA store can turn them.

I used an air chisel to nip the heads off the retainer pins. One bolt came out OK on the wheel cylinder and the other rounded off even with a 6 point socket. The air chisel solved that one too. Then I had a lot of prying with a 30" bar to pop the drum and shoes off but it did give up before I did.

[heyjoe]

Gale, glad to hear you got it. Sounds like it fought you every step of the way.

[gale]

When it goes back together I'll have the dummy slot opened up so I can adjust the brakes.

I understand the self-adjusting mechanism but I don't see GM's logic to not provide the hole for manual adjustment.

Perhaps it would have worked OK if not for rust.

[gale]

Latest update: found a place to turn the drums with the hubs attached but it was expensive. They actually needed very little to clean up.

New wheel cylinders, shoes, etc. are readily available but I bent the snap retainers to get them out.

Does anyone know of a source?

[Stocker]

Not sure exactly which parts you are referring to.... NAPA (and probably most others) sells brake hardware kits with springs and all the little twiddly bits, if you can't find the retainers alone.

[gale]

I bought shoes, wheel cylinders, and the hardware kits from NAPA today. This is the retainer snap ring that holds the outer bearing.

I could reach in with pliers and squeeze the snap ring open but it was still a bear to come out of the slot all the way around. So now it needs replacing and NAPA doesn't have it. I'll try the nearest Chevy dealer in the morning.

If that doesn't pan out I can probably straighten the bends and use them.

[Lee H]

Sorry, misread your post.

My 72 C10 does not have the slots and it's usually a chore to get the drums off.

[gale]

I know what the purpose of the slot is and it would have been nice if GM had provided one. There is a deep dimple just the right size and location for the slot so I'll drill that out while the shoes are off.