Rear Drums

[SUX2BU99]

If I wanted to just do a simple clean of the rear drums on the used rear end I bought, can I just wash it down with brake cleaner? Wash it off with water after or no? I took one drum off and they looked pretty good so I'm not interested in tearing them all apart.

[ccz145a]

I, too, am interested in anyone's thoughts on this procedure, Since I just did the same thing (without the water, just brake cleaner)

I just replaced my 3.73 12bolt open diff with a very noisy ring&pinion with my doner truck's 3.42 10bolt gov-lock. My truck brakes are fine and just sprayed off the backing plate and internals with brake cleaner, then did a quick spray pass down each shoe to make sure no grease got left there. Then bolted my brakes to my newly installed diff and never had to disconnect the parking brake.

It is still in the air with the drums off. But i'll be done soon and have a status report.

[SUX2BU99]

I'm interested in your procedure of how you removed the old diff and put in the new one, if you don't mind running it down quickly in point form. I have a plan in mind but I want to see how someone else has done it.

The brake lines on the new diff were all cut, so I know I will have to transplant a couple of items which are no big deal. So are you saying you removed the entire brake assembly, still intact and attached to the backing plate, from your old diff and then simply bolted it onto the new diff? That's an interesting idea. The parking brake cable was also cut but the boneyard guy said you just put a 12-point 1/2" socket overtop of whatever holds the cable one and it releases it really easy?

[ccz145a]

The parking brake cable was also cut but the boneyard guy said you just put a 12-point 1/2" socket overtop of whatever holds the cable one and it releases it really easy

Wish I'da known that, my method of working each little tang and finally getting the p-cables out of the donor was less than rewarding.

In point form:

Place some chocks at the front wheels

Using floor jack on diff housing, raise truck high enough to sit comfortably behind the diff cover.

Support with jack stands (6T) at the front of each leaf spring perch. This will let the springs sag a little when you let the diff down. Stay out of the way while lowering! While lowering diff, take the time to tap-set the legs of your jack stands with a hammer to relieve stress from time to time. I am doing this out in the gravel diveway, so I used a long 2x12 under the stands to keep everything close to level and supported.

Set p-brake and Remove wheels.

Unset p-brake and remove drums.

I determined at this point my brakes were just fine.

Cleaned brake assembly as stated.

I am replacing my rear brake hose, so I disconnected the hose up at the frame bracket and then disconnected the lines at each wheel cylinder.

Lower the differential, and get the jack out of the way.

Remove diff cover and remove the pin at the spider cluster. Push in each axle and extract the c-clips then remove axles.

Remove the 4 bolts holding each backing plate and swing each brake/plate assembly down to rest. Put something under them to keep the shoes off of the dirt (in my case, I had 2x12 to rest them on) the p-brake is still attached, no need to remove.

Replace axles, c-clips, and spidergear pin and put the diff cover back on. This will make someone a nice differential one day. All it needs is all new innards

Put the jack back under the differential and raise to support some of the weight.

Use a stout pull bar and a 15/16 socket to break loose the u-bolts at the springs. Then rattle off the nuts with an impact. Use a wire brush first to remove dirt and rust off the threads first.

more later. got to go home...

I am back. On to the list...

Once the u-bolts are free, go back and make sure the vent tube is disconnected at the bottom of the bed. Then drop the diff.

Manage to get a creeper under the housing and you can move it anywhere.

Reinstall is reverse, except you dont put the dirt back...  

Still in the process of putting everything back, got the backing plates on and the new brake hose and lines, drums. Still need to torque the u-bolts (thinking of getting new ones) then put the new housing gasket on and fill the differential. And I need to put a different u-joint to match the 10-bolt yoke.

I couldn't fine a torque value for the backing plate bolts (fine thread 3/8") so tightened them to 60 ft-lbs. U-bolts are supposed to be 140 ft-lbs according to Haynes.

Later.

[VileZambonie]

Washing your brakes with brake clean is a waste of money and needless exposure to more chemicals. Use simple green and water. Let them air dry before you put the drums back on.

[SUX2BU99]

Awesome, thanks Vile!

CCZ, I look forward to hearing more!

[SUX2BU99]

I'm having a problem removing one of the drums. It will wiggle a bit but it won't come off. It won't turn either. It seems as though the shoe is engaged. Perhaps the parking brake is 'on'? The other side drum was fine. What can I do about this to get the drum off?

[frogman68]

I'm having a problem removing one of the drums. It will wiggle a bit but it won't come off. It won't turn either. It seems as though the shoe is engaged. Perhaps the parking brake is 'on'? The other side drum was fine. What can I do about this to get the drum off?

Have you tried to back off the shoe adjuster ? Try tapping with a hammer ?

[ccz145a]

I had to use a hammer on my donor's drums. Just a couple of light raps at 90deg intervals around the back edge will do it.

When I say light, I mean that if your finger was in the way, it would hurt a little.

I used a 2.5lb beater.

[VileZambonie]

Take a BFH and strike the drum on the face side a few times to shock it. This will help break the rust.

[SUX2BU99]

I'll try that then. I had my rubber mallet out and was bonking on the edge of the drum trying to loosen it but it wasn't enough. I scraped out a bunch of mud and crud from between the drum and backing plate so I suppose there certainly could be some rust in there, especially if the shoe is sitting very close to the drum. I sure hope that's what it is. Having a stuck shoe I'm sure would really suck to get loose. I haven't touched the adjuster wheel yet. Which way backs it off?

[VileZambonie]

http://forum.73-87chevytrucks.com/smforum/index.php?topic=5029.0

[SUX2BU99]

Wow, was that ever helpful! Thanks Vile. I've been on this forum when that thread was posted originally but I don't remember it. What Pugsy123 said was interesting because the drum will wiggle about 1/8" if I put a flat screwdriver between the drum and backing plate and try to move the drum. The drum won't turn though so I will try backing the adjuster off. If I'm looking at the backside of the backing plate, do I push on the adjuster at the top or the bottom of the star wheel to back off the shoe? Or, in other words, turn the wheel up, or down?

[SUX2BU99]

Okay, I'm getting really choked here. The drum is stuck on there I'm sure because the brake shoe is engaged. I can wiggle the drum so it isn't rust-stuck. With a crowbar inside the lip between the drum and the flange I can move it 1/8 to 1/4". And when I wiggle it, I can see the cut e-brake cable moving too. The boneyard monkeys cut the e-brake cable and left a few feet of it. So what do I do? Where are these knock-outs on the backside of the backing plate? I see none. I see some dimples around the perimeter. Are those them? When compared to the drum I have off, those dimples don't line up with the adjustment wheel. HELP!!

[VileZambonie]

Does the wheel turn freely? If so the brake isn't stuck on. Look in the hole with a flash light. Take a small pocket screwdriver and move the adjuster lever out of the way. then rotate the star wheel backwards. It will wan to click in the tightening direction and lock in the oposite direction. Moving the lever out of the way will allow you to rotate it backwards so the drum will come off easliy. Take a pic so we can see what you have