12 bolt swap.

[SUX2BU99]

Here's some pics of my in-progress swap. So far it's just been prepping the 'new' diff for installation into my truck.  Here are pics and descriptions as taken from my cardomain.com page.

This is a page showing the new 12 bolt rear end that I have bought for it. It came from another 81 shortbox and to my very pleasant surprise, it is a 3.40 factory posi! I was looking for a 3.42 posi and all I know about this was it was $150, out of the truck and would fit my truck. Guy said it was a 10 bolt. Nope, turned out to be a 12 bolt and when I took the cover off, I couldn't believe it was the ratio I wanted AND a factory Gov-lok limited slip! The guy selling couldn't believe it either and said if he knew it was a posi, it would have been double the price. Score! http://www.cardomain.com/ride/3001366/2

This is it after I got it home. Sat outside for a year so covered in surface rust and some oil spots.

The one drum came off fine. This one was STUCK on. The brake was totally engaged and there was no slot to back the adjuster off. I had to hammer it off with a ball peen and a crowbar from the back side a little at a time. It sucked, but it finally came off.



This is the diff in my truck now. 12 bolt with 2.76 open carrier. Doesn't work all that great with my new cam and heads so out it goes. I'll be swapping over the brake lines and the chrome cover I just had put on it in May 08.

I had a lot of trouble getting the lines off. One bleeder busted off, the other one came off with repeated short tugs on the socket wrench. Both brake lines wouldn't budge even with a flare nut wrench. I had to cut the lines off at the nut and then use a socket. Penetrating oil didn't seem to do squat.

I used a wire wheel in my drill and went over the whole thing to remove as much surface rust as I could. It removed quite a bit. The cover and drums I did not do as I won't be reusing them. I then sprayed it down with Simple Green and washed it off, then blow-dried with my ShopVac and let it air dry overnight.

This is how I move this thing around, since I have to get my wife's Tahoe back in the garage at night. It's ghetto, but it works. Make no mistake, these diffs are HEAVY. For sure over 200 lbs

And here it is with Chassis Saver gloss black paint. This stuff is awesome! When dried it's very hard and feels like thick powdercoat. I put 2 coats on. Very little of this goes a long way. I bought a 1 qt can because I thought I would need that much. I bet the tiny 4 oz. can would have done the truck. Use gloves though!! I didn't have to do the drums and cover, but did anyway since I had so much left over in the little tin I poured some in to in order to paint it.

Another view

Here you can see the texture difference. The axle tubes I have wire brushed. The cover I have not. The paint is nice and glossy but it develops bubbles and such underneath it so it's not show-car perfect but it will look good and new under my truck. Now it awaits removal of the brakes to get the parking brake cable off, and then installation in my truck.

[dumbucket1]

Cool! bet you cant wait to get her in 

[cracker0169]

looks good! drop those drums off and put on some discs!

[werewolfx13]

Looks good, I second the disc brake upgrade..

Interesting way of moving the diff around, it works I suppose..just easier to carry them if you don't have far to go, IMO..

[gerardo0367]

Where did you get the Chassis Saver gloss black paint did you get it from eastwood ?

[SUX2BU99]

^ Thankfully a local hot rod shop carries it. They carry POR15 too after everybody asked him to stock it, but nobody buys it  lol  They buy the CS stuff though.

Nah, no discs right now. I'm challenged enough trying to find DETAILED info on the 'net about removing the drum brake assemblies, let alone swapping to discs.

Carry the diff? Well maybe if one end was on the creeper but there's no way I'm going to try and Hercules that thing around myself  lol  It's heavy and awkward.

[SUX2BU99]

Update: stripped down the pass side brake assembly, and took lots of detailed pics. Bought new Raybestos shoes, springs and wheel cylinders. $99 w/ tax, along with the brake spring pliers and hold-down spring tool ($17 w/ tax). Wire-brushed the backing plate and painted it with CS, along with the other hard parts that did not come with the new kit.

Throughout the week I hope to have the pass side reassembled, drivers side stripped down, cleaned, painted and reassembled. Over the weekend I would love to have the diff in my truck removed and who knows, maybe even the new one installed. Lofty goal though.

[cracker0169]

Later this summer after I do a motor swap I plan on adding rear discs on both my 2 & 4 wd trucks.
http://www.blackbirdscustomtrucks.com/index7.html

[SUX2BU99]

Okay so made some progress with the one brake.

As original:

Stripped down and wire-brushed:

And reassembled with new springs, wheel cylinders and shoes and painted with chassis saver:

[ccz145a]

Nice!

[cracker0169]

looking good! Be sure to add a line lock to your front brakes so that you dont mess those new shoes up when you do some burn outs!

[SUX2BU99]

^ No doubt. At the drags last Friday I saw a guy whose line lock didn't unlock on him fully and he smoked the drivers front tire all the way down the track.

Tonight I got the drivers side brake tore down, wire brushed, and all parts repainted. Reassembly tomorrow And then it's prep time for the swap. Woohoo!

[SUX2BU99]

I figured I'd run down a plan of attack on how I'm going to remove my diff in the truck. If anything looks wrong, please let me know:

- raise truck with tires off the ground and support it. Remove wheels, drums and disassemble brakes so parking cable can be removed. Reassemble brakes, and put drums and tires back on
- remove brake lines from diff at the distribution block that bolts onto the diff housing since I believe this is connected to the rest of the truck with a rubber hose that cannot be removed without cutting it
- unbolt u-joints from driveshaft and diff. I think this is just as easy as undoing bolts right? Anything special to know here?
- lower truck enough so weight is taken off of suspension but tires still touching ground. Support with jackstands at frame rails, loosen and remove u-bolt nuts and u-bolts
- raise truck so that diff can become clear of contact points with leaf springs. This will have to be done one side at a time since all I have is a floor jack
- roll diff out of the way

How does that sound?

[Captkaos]

Looks like you got it covered. 
You can remove the hose from the truck but you have to remove it from the hardline.
u-joints= nothing special
If you are taking your tires off you won't be lowering it with them still touching the ground....
I put the jack at the center of the pumpkin and lower it all together.  You should be able to balance it from one side.

[ccz145a]

The u-bolts for the axle will be a lot easier to remove when the tires are out of the way. You are going to want to clean the theads with a wire brush and spray some pb blaster on them and use a long cheater pipe to break the nuts loose.

Support the diff with the jack and the wheels removed, not using the ground with the wheels on.