Re: 1977 rear gear swap

by Dinomyte Wed Jun 25, 2014 10:07 am

Thanks John

by Dinomyte Mon Jun 30, 2014 12:08 am

Just an update - spend half the afternoon with son number one getting the old rear end out, spent the other half of the afternoon working on the one stubborn LCA bolt. It's soaking tonight and will be getting the torch tomorrow if it doesn't co-operate.

The axle has the smaller backing plates on it from '75 and older, didn't notice that till after the parts store closed. If the old ones aren't too bad we'll take them off. . .

by chevellelaguna Mon Jun 30, 2014 8:22 am

I've always only used the GM friction additive. And put the whole bottle in, it was a 4 ounce bottle. You should be able to get it from your local GM dealer. If not, I've seen 4oz bottles made by Yukon on eBay motors.

by Dinomyte Tue Jul 01, 2014 8:49 am

The axle is out, the bolt head was seized / fused right to the axle housing, we ended up cutting it out, after heat and chemicals didn't work!!

Now it's get the backing plates moved, break lines made (got this cool new break line tubing that is bendable by hand and not kink-able. It was a couple of bucks more than the regular stuff but I think well worth it if it's half as good as they say. I'll post the name of it later.) Also new shocks, and a whole set of bushings, plus a '94 Impala SS sway bar.

by dynchel Tue Jul 01, 2014 9:23 am

Now it's get the backing plates moved, break lines made (got this cool new break line tubing that is bendable by hand and not kink-able. It was a couple of bucks more than the regular stuff but I think well worth it if it's half as good as they say.

[/quote]

That would be the gold colored ez bend line (S,U,R,&,R makes it) At my work that is all we use do to its ease of use and good flaring properties. It is suppost to not rust either. Exclamation

by Dinomyte Tue Jul 01, 2014 10:34 pm

Spent my day in the garage, got the backing plates off the old axle, cleaned, primed and painted too.

Shocks and a couple of control arms out too.

Got the backing plates on the new axle off the retaining bolts - I hate POR-15 ! Why the devil to people assemble and then paint, and I mean paint, even the backing plates and the treads of every bolt! That stuff makes it a son of a mother to undo a nut.

Now that my rant is over, the question.

Does the auburn posi hold the axles in the same way as my open OE did, with a bolt holding a pin in place and a couple of C - clips or is it something different?

Just wanted to make sure I had at least an idea before taking the cover off.

thanks

by Joe73 Wed Jul 02, 2014 12:07 am

Yes, the auburn also uses "C" clips. You can do away with them if you install C clip eliminators.
Just finished doing some more research of the Auburn. Just decided to upgrade my rear to an auburn and toss the GM posi unit. Will be ordering tomorrow.
This will be my 4th auburn install in various vehicles.

by Dinomyte Thu Jul 03, 2014 8:38 pm

I've got all the control arms out and getting new bushings pressed in tomorrow. I was looking at the control arms and I couldn't tell the difference between the left an the right, so I marked them. I was wondering is there a difference?

I was also wondering about insulators. Energy suspension is the only option, but there will be a three week delay to get them. Anybody got another option?

Right now the best choice is to put about 6 inches of heater hose on the spring (slide the hose over the spring - like Ford does for some) which is about the same thickness as the isolator and then install the springs, second option is to install the old isolators which are in incredibly poor shape.

by Joe73 Thu Jul 03, 2014 8:45 pm

I bought normal rubber insulators. Here's some part numbers from rockauto.

ACDELCO Part # 45G18001
MOOG Part # K62032
RAYBESTOS Part # 5771100B
RAYBESTOS Part # 5771100

I'd call around to some local parts stores. You should be able to come up with them pretty easily. I stuck with rubber because of all the poly in the arms front and back. I went with the recommendation of multiple forums (including ford forums) that say not to use poly above your differential. Use good quality rubber there. Reason being, when the rear articulates, those short upper arms bind and tear at the arms and cross member above the rear axle. There's even a youtube video about it.

by chevellelaguna Thu Jul 03, 2014 9:18 pm

You can swap out the old isolators for new ones (when they arrive) easily by unbolting the lower shock mounts and pulling down on one side of the axle, leave the wheels on, the coil spring will basically fall out.do one side at a time.
The lower and upper control arms are not side specific.

by dynchel Thu Jul 03, 2014 9:43 pm

I bought new isolaters on eBay. Pretty cheap (less than $10.00) they are even a sexy red color. Gay

by Dinomyte Fri Jul 04, 2014 12:44 pm

Joe73 wrote:I bought normal rubber insulators. Here's some part numbers from rockauto.

ACDELCO Part # 45G18001
MOOG Part # K62032
RAYBESTOS Part # 5771100B
RAYBESTOS Part # 5771100

I'd call around to some local parts stores. You should be able to come up with them pretty easily. I stuck with rubber because of all the poly in the arms front and back. I went with the recommendation of multiple forums (including ford forums) that say not to use poly above your differential. Use good quality rubber there. Reason being, when the rear articulates, those short upper arms bind and tear at the arms and cross member above the rear axle. There's even a youtube video about it.

Thanks for the part numbers, that made things easier. I got a set of Moog ones coming for Monday, from a different parts store. I guess they take the year and figure they can't get it . . .

by Dinomyte Fri Jul 04, 2014 9:39 pm

HELP !? I got to the point where I was going to pull the axles and replace the backing plates on the replacement axle with the freshly painted ones from my old one. I got the cover off, to discover the the bolt that holds the centre pin in place is well rounded, and overtightened, cause even vise grips didn't budge the thing.

Any thoughts on getting the thing out? I've been looking online for wrenches like the sockets I have to remove rounded bolts but no luck so far.

by dynchel Sat Jul 05, 2014 6:56 am

A llitle heat may do the trick (hopefully the retard that did that didn't apply red locktite). Try to heat the carrier where the pin screws in, that should expand it enough to break it free. (And burn out any locktite if its there). Good luck.

by Dinomyte Sat Jul 05, 2014 7:47 am

dynchel wrote:A llitle heat may do the trick (hopefully the retard that did that didn't apply red locktite). Try to heat the carrier where the pin screws in, that should expand it enough to break it free. (And burn out any locktite if its there). Good luck.

Would propane heat it enough? also what about the rest of the springs, clutch plates etc that are in there, will heat damage them? or do I just need to be careful like a reasonable person and it will be fine?

Thanks again, and again for all the sound advice.

by Joe73 Sat Jul 05, 2014 7:49 am

Oh yeah, I've run into this problem a couple of times. I've never had a rounded center pin bolt because they usually break off.
I agree with dynchel, if you can get a grip on it somehow, heat the carrier and try to turn it. Remember, the bolt only has threads from the bottom of the head to about 1/2" down. The rest of the bolt is smoooth.
I found that "left handed" drill bits are your friend. They dig while your drill is in reverse. So while drilling a hole, the bit is turning the bolt counterclockwise (because your drill is in reverse) and sometimes you luck out and the bolt unscrews itself.
I usually have some 1/8" left handed drills in the 2 1/2" and 4-6" length on hand. And a powerful magnet as well. In case you get the top of the bolt out, the smooth part usually comes out with a magnet.
Worst case scenario, and it a real pain, you have to drill the hardened cross pin close to the carrier to basically "cut" the broken bolt and allow the cross pin to slide out. Then just get a new cross pin.

Here's a kit I found recently on Randys Ring and Pinion. Dont know how good it works but it looks interesting. Dont know if its a left handed drill bit but I would use one instead of the one in the kit.
http://www.ringpinion.com/b2c/ProductDetails.aspx?ProdID=8986&Product=YT_BE-01&Brand=Yukon_Gear_and_Axle

I usually get my left handed bits from MSC Supply. !/8" and 1/4" usually do the trick for anything I need. I figure, if you have to drill a hole for an easyout bit, why not use a left handed bit. I've lucked out most of the time with the broken bolt unscrewing itself while I'm drilling the hole.

by Joe73 Sat Jul 05, 2014 7:51 am

If you get a good grip on it, heat it up good. I'd even use MAPP gas instead of the propane. Grab a bottle of that, it uses the same propane heat and its way hotter. Your heating the little area between the edge of the cross pin and the head of the bolt. Thats the only spot where the threads are.
Anything with loctite on it has to be heated to bread it free.

by bracketchev1221 Sat Jul 05, 2014 11:12 am

Like joe said, the area you have to heat is so far from the internals you'll be fine heating the bolt area.

by Dinomyte Sat Jul 05, 2014 11:24 pm

OK so I'm not close enough to heat anything I don't want to, that's good to know.

How about leaving bolt shards from having to handle the mangled bolt head with something like vise grips? Will it be enough to dump the gear oil after 500 miles and hope that anything will come out with it? Or is there a better easier way to make sure I don't leave little bits of metal in there?

thanks

by Joe73 Sun Jul 06, 2014 7:34 am

I think you will be fine. Everything in there is tacky from the gear oil so it wont be all over the place. Maybe stuff some rags into the carrier itself so nothing can go in there. When you start heating you can always spray the rags with some water to keep them from igniting. I never did any of the rag thing but just cleaned everything up with some brake cleaner when done.

by 1973 454 MONTE Sun Jul 06, 2014 9:53 am

i snapped off the bolt in my old rear end. (way to many burnouts)
1977 rear gear swap - Page 3 Img_0410

could not even get the axles out.
1977 rear gear swap - Page 3 Img_0411

by Dinomyte Sun Jul 06, 2014 11:39 pm

ouch, 1973 454 MONTE.

That's got to be one freaking huge burn out. . . . Smile

Here is the second last piece of the puzzle for the rear end.

1977 rear gear swap - Page 3 Swayba10

Yes the sway bar from a '94 Impala SS, picked it up yesterday in Toronto. I'm wondering if having it chromed would be a bad idea? I'm wondering if the flexing will cause the chrome to fail? Going to ask the folks at the plating shop tomorrow.

by dynchel Mon Jul 07, 2014 7:01 am

Years ago I had a aftermarket "chrome" sway bar from JC Whitney. It looked kind of cool. I don't think that bar will flex anywhere neat enough to damage chrome.

by Dinomyte Tue Jul 08, 2014 11:32 pm

Heat, hammer and chisel along with 20 minutes of effort and the bolt came out.

Lucky for me there was no thread locker in there, and out came the axles, swapped the backing plates, added the break cylinders, and called it an evening.

The last part of this rear end swap showed up yesterday. Thanks Dynchel (aka John M) for the sway bar inserts. I'll be setting up to figure out a good position for the bar and drill the lower control arms probably tomorrow evening.

by Dinomyte Sat Jul 12, 2014 7:12 pm

I got everything mocked up this morning to figure out where the furthest back position I could mount the sway bar was, and I think it's way too far back.

I can get the insert installed about 1" in front of the bushing. That means the insert is too low and too close to the rolled lip of the LCA.

This is what I think I should be doing.

1977 rear gear swap - Page 3 Dsc02410

This is the side, and the green tape is the back edge of the insert, just a little in front of the lip is where the first bolt hole attaches the insert to the LCA. The zip ties are just inside the bolt holes.

1977 rear gear swap - Page 3 Dsc02411

I can get the inserts further back, but I don't think I really want to.

Any suggestions or confirmation would be greatly appreciated. I don't want to make a mess of what may be the last two LCAs in Canada.

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