what the heck - tried swapping a 71 rear into a 63 c10 and its not close

yeah i had already done the disk swap in the front with a 79. i stumbled upon the 71 a couple weeks ago to use the 250 from it in my 48 chevy car build. but the rear end was also a huge factor as i thought it would all bolt in. i already cut up the 71 chassis as i couldnt keep it all in the driveway so of course thats junk now. i really think my 63 is stock - i cannot figure out what the heck is going on. i get the panhard bar issue thats fine but the axle pads locations should be the same??? odd

 

Did you measure how far apart the spring perches are on both of the rearends you have?

 

i will when i get home tonight. i guess my question is more hypothetical in that "shouldn't" a stock 71 drop into the stock 63 - minus the panhard differences? i thought that was why so many people recommended using the 71/72 rear as it would save me from relocating the axle pads? i know just enough to be dangerous and dismantle a project lol.

 

ok so i posted some pics here: http://neverwintercycles.com/autos-1963-c10.php and ill post some here as well. note the gap in the drivers side between the trailing arm and the axle pad. obv nothing is tightened down but i am wondering if that twist is causing things to be off? i measured the axles and the stock is actually wider between the lips of the drum backs. the stock measured 571/4 between them and the 71 measured about an inch less.

the last pic is the stock axle.

i am at a loss.

 

Measure the width of rear ends where the wheels bolt on, that's the measurement that will be wider on the newer rear end. The brake drums are wider on the later model, so the inner measurement will be shorter.

When you are swapping the rear end on these trucks, it helps to support the truck on jack stands that are placed under the frame, not the trailing arms. Then the trailing arms are free to move to where they need to go to bolt to the rear end. The way you have it supported, the trailing arms are holding up the truck, so you can't move them as needed to fit the rearend.

did you measure the spacing between the spring perches on both rear ends and compare it?

 

yeah that dawned on me as i was taking those pics - i need to resort the jack stands. will do that tomorrow. i am really hoping its an 1d10t error (idiot on my part) by not jacking things properly. i tied to measure the spacing but couldnt get an accurate read so i am going to try that tomorrow as well. do you think pehaps loosening the bolts at the other end of the trailing arms to give them a bit of slack may allow me to get them into place to where the axle pads are in alignment? i will try to sort it again in the am. thanks for the help.

 

As Squirrel said, put both rears next to each other and make the new one match the old one. In a sense, all you have to do is torch the brackets off the old one and weld them onto the new one. Pinion angle will be taken care of this way. This is hot-rodding.

Bro, I dont mean to be a jerk (although I like to play to my strengths), but I cant believe you thought swapping a whole different year rear would be easier than refreshing brakes and seals (you didnt mention bad gears or bearings). Youre going to be a great fabricator soon.

 

Yes

No

Yes, do this. The arms might want to hang down too much, so you may need to hold those up slightly with a block on each one. That might keep them more stable if you don't have a helper.

Those arms are designed to be twistable, so uneven jacking or a spring pushing sideways a bit, can twist the arm. If you still have the twist after trying squirrels advice, borrow a huge pipe wrench. Drop it over the top to pull down, which will twist it straight, while you get the U bolts through.


You are close, don't worry...unless those stands slip

John, he has 5 lugs up front after the disc swap, so now he is using a 5 lug rear to match, instead of the original 6 lug rear

 

Did not know that.

 

awesome thanks all. will be out there first thing in the am. hope it gos well lol.

 

Just got into this same thing on a 62 stepside. Freind thought it was a bolt in deal. Turns out the perches needed to be moved in about 1 inch on each side. I put the old rear end on a set of jack stands then leveled the perchs and recorded my pinion angle with the perches level. Once i was done there i cut off the perches and aligned then on the new differential with the pinion angle set and leveled the perches. it goes down the road with out a vibration. Just my 2 cents hope everything works out for you.

 

You don't know how to weld? Maybe this is a good time to learn.

This is probably something that you don't want to hear but maybe it will help someone else out, hot rodding is not bolt together. Nothing ever fits exactly right and even if it does something always needs to be tweeked to make it right.

Anyway maybe this is your chance to learn how to weld.

 

Back when I was your age.....I welded spring perches on with an AC stick welder. It wasn't a big deal.

 

i can weld however i have no problem admitting that i would rather pay a professional 50-100 to final weld something that can save my life - or someone else's. i also opnly have a 110 and i wasnt sure if even with multiple passes if that would be strong enough on the axle pads.

i dont expect everything to be bolt together - however sometimes working smart is better than working hard. now if you are like me and seem to fail at BOTH well thats a different matter lol. i have welded things on the truck, other projects, etc but when it comes to something that can kill me i have no issue admitting my lack of expertise. and while i agree that hot rodding is not about making a full size snap-together model, there is something to be said for researching and trying to find what you can that will bolt in in order to spend what little free time one has on items that are most definately not bolt in. i have about 3 hours a week to work on stuff so i try to find that balance of bolt on and fab. hope that makes sense

 

WHOO HOO i am an idiot. what a total dolt. so all i had to do was jack the truck up by the frame and NOT the trailing arms. 5 mins i was done. now on to the next challenge: coupling the driveshaft to the 71 pumpkin. the 63 driveshaft is different so i am trying to sort what makes more sense: swap the connector pieces on each pumpkin (basically put the piece from the 63 onto the 71 so that it mates to the 63 driveshaft)). or swap the 2nd leg of the 2 pice driveshaft from the 71 onto the 63. as usual i am prob overcomplicating it but i am ahppy i discovered my own idiotic problem!

 

Go by a bastard joint. May not hurt to bring both U joints with you if you have them.

 

i fixed it - at least i think i did. as usual i was overthinking. all i had to do was find the damn end caps and bolt em on. duh. ill have my mechanic check everything once i am done anyway but i hope this gets me moving. gotr the seat out too. taking friday off to try and sort as much as i can.

 

Good to hear you're making progress. Notice that posting pictures of what you're doing helped us figure out how to fix it. Keep that in mind next time you have a problem you can't figure out.