Swapping Rears

[lukecp]

Well, the time has come for me to swap rear axles in my '72 C10 (coil spring 12-bolt). The old one is still functional, but on its last leg.

I shoud pick one up sometime this week, if not tomorrow. To check out the junkyard rear i plan to pop the cover, check the gear ratio (looking for 3.07), look for any metal particles in the fluid, look at the contact patch on the gears, and check for excess play in the pinion.
Any other suggestions? I don't want to put another junk rear in my truck.

The install looks pretty straight forward. Just unhook the brakes at the rubber hose, plug the line, remove the tracking arm, remove the driveshaft, then unbolt the U-bolts and slide the axle out (my e-brake cables are gone, so i don't have to worry about removing them). That sound pretty good?

Also, how should i go about suspending the truck in the air? I don't want it to crush me, lol. I was thinking of blocking the frong wheels, and putting jackstands on the framerails infront of the rear, and behind the rear too. And sliding the rear out from the side....if that is possible.

I have never done a rear swap before....but i do have mechanical ability and am not afraid to tear into it.

Any help is greatly appreciated

[Longhorn Man]

You won't need 4 jack stands just to support one end. 2 is enough. U would place them in front of the rear axle.
You will probably be needing an impact wrench...and maybe even a hot wrench.
My truck spent most of its life in Kansas, and then 10 in Tx untill coming up here less than 3 years ago. My impact was just bareley able to remove the nuts on the U-bolts, even after heating them...and our compressor is turned up to 120 PSI.
You'll also want new U-bolts and nuts too.

[dinnut]

and most importantly.... HAVE FUN . did you burn this one up doing burnouts? you should go out in style. put an old tire on there and try to burn up the old rear end.... lol

[stelth2002]

Dont push the luck. If it was me something would probably go terribly wrong.

[Rooster's 67]

definantly be prepared for new U bolts then you can just use the blue tip wrench to remove the U bolts. other than that sounds like you got the general idea.

[lukecp]

Thanks for the help guys!

I don't have access to a real torch for the U-bolts...but i do have a crappy little berns-o-matic (maybe the heat will help?).

Think a 3/4" drive rathchet and a huge cheater bar will get them off? They don't look too corroded...but i will soak them in some PB blaster and hope for the best.

BTW, i don't think i will ever post burnout pics again! All the hell i have recived, lol....oh well, its all good

[Paul72]

THere's nothing to the swap, really. Since you're going to get new u-bolts anyway, I would use a sawz-all to cut the old ones off. Be careful, tho, cuz they do pop due to the pretension in the bolt - nothing that will hurt you, but it scared the crap out of me the first time! Use a floor jack under the pumpkin to lower and roll the old rear end out.

You decided against the gear swap?

[Longhorn Man]

Yeah...don't complain about tire wear either. I learned that one last year.
As for the propain torch and a breaker bar...I tried that once, and my back hurt for a week. After the week was up, I got to try again.

[lukecp]

Yeah Paul, i decided to get 3.07 again. I gotta be smart about the ratio....since i do drive the truck on the highway alot...and a OD tranny may not be in my budget for quite some time. Oh well....one day i will get 3.73's

I might be able to borrow a sawzall if the bolts don't break loose...if all else fails i could rent a torch, but i don't want to pay $30, lol. Or i could spend sevral hours with a hacksaw, lol

Thanks again guys!

[boraxman]

Nuts broke loose on mine after pen oil and heat but I still had to beat the u-bolts off. Figure on new ones for sure...good luck and may the force be with you!

[Tx Firefighter]

The nuts are always do-able. It's the u-bolt getting rusted into the holes in the trailing arm that's the problem.

Definitely douse them in PB Blaster daily for awhile before trying to remove them.

[PR454SS]

I broke two half inch breaker bars trying to get mine loose, finally haad to get 3/4 in drive and heat them with a torch. I think it would be a good idea to get the U bolts from the donor truck as well.

[tom hand]

Soak the nuts for as long as possible before you start, then really CLEAN the exposed threads on the u-bolt with a wire brush...makes a big differance. After you get the nuts off, reinstall them till they are flush with the end of the u-bolt to beat the u-bolt loose from the trailing arm, so you won't mess up the threads. Don't even start till you have at least a 3/4 drive breaker bar...1/2 won't cut it...have fun

[rodnok1]

sawzall em off or your hate life, you could try a sabresaw. Either way buy a pack of good(read not cheapos at walmart) blades. When installing don't forget to align it properly, I would check the wheelbase on both sides before you tighten the ubolts up all the way to make sure it won't dogtrack on ya.

[old Rusty C10]

you can use a vice grip to plug the brake line and if you block the front wheels you only need a set of stands under the frame rails in front of the rear end you can lower the rear end with the floor jack and it always helps to have a buddy there for the swap /
the night before id throw some liquid wrench or equivalent on the U Bolts and like two days after the job is complete make sure ya re check the u bolts
also air tools are very helpful in this situation

[Rooster's 67]

side note:

be causious of clamping brake lines with vise grips, old lines can collapse inside and cause problems. Get a fitting from the parts house to plug that line or you can get plugs made of rubber off of the tool trucks.

[Gene]

If you have access to a 3 inch side grinder that will cut them much faster than a sawzall. Discs are really cheap, you can usually rent these from a equipment rental place.

[rambler]

Doing the same swap right now.. bought a parts truck from teeit up, and got them both in my shop building end to end.. my truck actually came off with only PB Blaster and my big cheater bar,, with a long pipe "extension" on it... the other was a differnent story.. had to cut them out with a grinder, no torch here, and then remove the trailing arms and beat them out of it with a sledge.. they were rusted in solid.. I plan on putting the bad rear end.. (bearings are loud and leaks through seals) back on the parts truck to move it around till I pull the engine for the 67 later this summer.. got cold and no heat in my shop,, so will wait till this weekend to get it finished.. got to go to chevy duty this week for U bolts as no auto parts store seems to have them???? they all say their bigger then they stock,, its just a C-10 with auto 350... hmmm... now the biggest concern is of course making sure it is all aligned... when I put the good one on my truck. Air tools are great,, if its not too rusted.. as the parts truck was, got to replace my rear brake lines too, as they are rusted so bad that I could not remove the rubber line.. so had to just cut it....

[lukecp]

Well, i went junkyarding for a few hours today and finially found a 3.07 rear off of a '72 GMC....$150 and i pick it up tomorrow pulled out of the truck. I poped the cover and everything looked good.
The one for $125 had 3.73 gears in it when i looked at it.

Once again, thanks for the tips. I will proably start on it on Friday...hopefully i can get it done in a day.

I do have an angle grinder and some cut-off wheels.....forgot about that, lol. So the U-bolts shouldn't be too big of a deal, i hope anyway.

[lukecp]

Update:

I finished the rearend swap today
Like you guys said, it was super easy. I started on Friday, and worked a few hours each day until this afternoon when i finished it up. I recruited a friend to help me so it went pretty easy.

The u-bolt nuts came right off after a night's soaking in PB blaster. I did have to put a cheater bar on the 3/4" drive, but a firm push with both my feet broke them loose.
They were still rust welded in the trailing arms though, so i had to cut them off with a angle grinder and a cutoff wheel. Like Paul72 said, they popped because of the pre-tenision and scared the crap out of me, lol.
I was able to beat the remanats of the U-bolts out of the trailing arms after another night's soaking in PB. Then the new one went in without a hitch.
I did have to use heat on the tracking arm though....the nut didn't want to come off. Even with a little propane torch's help it was still a PITA.

The new one dosen't howl or anything, dosen't leak yet (knock on wood!!), and the brakes even were in good shape from what i could tell (couldn't pull one of the drums off).
And i did actually enjoy putting it in....remids me of why i love these trucks so much...easy to work on!

Once again, thanks for the help

[Blue_71]

i foudn out about that popping thing when i put a lift on the front of my K20... i dont think ive ever turned off a grinder and jumped out from under a truck so fast in my life!!!

hope your new rear holds up good for ya, and no more of these!!

[cdowns]

while you have the rear out it's a good time to check the bushings in the trailing arms for wear, i'd also suggest getting new bushings for the pitman arm,

[dinnut]

hey, im not giving you hell for doing burnouts. id like more burnout pics. i like burnouts. good luck with that rear end

[dinnut]

burnouts r awesome!

[lukecp]

I know you guys wern't giving me hell....but evey time i post a driveline problem someone mentions my burnouts!

Burnouts are fun though....just expensive!

The reason i bothered taking burnout pics of mine was becasue my tires were bald form other burnouts, as well as living on a dirt road, and i wanted to "finish them off".

I sure did finish them off, lol. The right rear tire completley lost all the tread surface...it didn't seperate or anythign, but it started to chunk off in little pieces. I bought new rear tires the other day....the guys at the tire shop got a kick out of my anniliated 255/60
Now i have 275/60's on the back....they are larger and don't spin as great....but they howl instead of squeal when i do light them up