72 Skylark Rear Axle locating....

What seems to be your problem or what are you trying to accomplish?

If everything is straight you should be able to simply bolt it in and be within specifications.
 
racers have been using STRING to establish how straight their frames / alignment are for decades.

http://www.circletrack.com/chassistech/ctrp_1204_determining_wheel_alignment_string_your_car/

there's not any adjustment built into the rear suspension, that's normally assumed to be 'aligned' on a straight axle car. the front suspension is adjusted in relation to the rear.

if the rear is significantly cattywampus you'll have to take the car to a frame shop and have it straightened ( ie - they'll chain the car down on a frame machine and literally bend the car frame until it's in the shape you want ) unless you can establish that one or more of the rear control arms is bent or significantly shorter than it should be.

Bob has an article up on how to fab your own boxed lower control arms which is very good.
http://www.teambuick.com/forums/view.php?pg=building_trailing_arms
 
Well, my buddy got a basket case 72 with non stock rear end (A project gone horribly wrong) where the arms won't fit to the axle (and they are long gone) and the mounts on the frame are still there.

Frame looks straight, just want to make sure (whichever way he decides to go on the project) that when it's installed, it's in the correct position and looks stock. Maybe a measurement from the C/L of a mount to the C/L of the axle tube? I just don't know.

He just doesn't have anything to really go from and I figured a post here would pick a few brains and see if anyone has had to do this before.

Steve
 
I think I must be missing some critical point here, so please bear with me. What I don't understand is why you can't install a set of stock 72 arms and a stock 72 rear (or interchangeable equivalents). Are you saying the frame and/or frame brackets have been modified?

Ray
 
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He probably could, but the axle he has (if he put the brackets on it) would probably be in the wrong spot because of the axle tube diameter difference. The mounts are still on the frame, but they look molested. I was poking around to see if anyone knew where it is exactly located and maybe how to figure it out.

Could I use the wheelbase to figure it out? If he puts the frame level (and the spindle perpendicular to the frame) and measure C/L of spindle to C/L of axle tube?

Steve
 
Ohhh, now I get it. You want to use the rear end you have now, not the stock one for a 72. Thank you for clarifying.

Ray
 
i have what you need

I have a date coded posi from a 72 , I can take measurement's , it is not in the car, factory 10 boltIMG_0462.jpg:shield:
 
The mounts are still on the frame, but they look molested.



ooooooohhhhhhh boy.

well.

on the plus side ... now you can set the suspension up however you want? cause, seriously, you've got a non-stock axle ( 9" Ford? ) AND what appear to be modified frame mounts you may as well start over from scratch. if for no other reason than simply because YOU HAVE TO BE NUTS TO TRUST THEIR WELDING ON THE FRAME MOUNTS.

even if the new mount locations are aligned and positioned properly you must be able to trust those mounts. i've had the axle fall off of a car while i was driving it. it ain't no fun. and usually, if somebody is going to swap a 9" Ford into the car, they have the Ford axle modified so that the it conforms to the GM standard mounting positions, not the other way around. these boys don't sound very bright.

the simplest solution would probably be to just scavenge the junk yards til you find a trash car with a frame in decent shape and just take the frame and rear end and slam them under the car you've got.
 
stage3matt said:
I have a date coded posi from a 72 , I can take measurement's , it is not in the car, factory 10 boltView attachment 3750:shield:
Click to expand...

If it's not too big of a pain, I could use the measurements from axle shaft C/L/ to some reference point on the frame. Not to the original mounts, just to a reference hole. The original mounts look screwed up and I will not trust them.

I did find out that measuring from the back body mount hole C/L to the center of the wheel opening is 18".... FWIW, I guess....

Steve
 
bob k. mando said:
The mounts are still on the frame, but they look molested.



ooooooohhhhhhh boy.

well.

on the plus side ... now you can set the suspension up however you want? cause, seriously, you've got a non-stock axle ( 9" Ford? ) AND what appear to be modified frame mounts you may as well start over from scratch. if for no other reason than simply because YOU HAVE TO BE NUTS TO TRUST THEIR WELDING ON THE FRAME MOUNTS.

even if the new mount locations are aligned and positioned properly you must be able to trust those mounts. i've had the axle fall off of a car while i was driving it. it ain't no fun. and usually, if somebody is going to swap a 9" Ford into the car, they have the Ford axle modified so that the it conforms to the GM standard mounting positions, not the other way around. these boys don't sound very bright.

the simplest solution would probably be to just scavenge the junk yards til you find a trash car with a frame in decent shape and just take the frame and rear end and slam them under the car you've got.
Click to expand...

Sure makes it tough, though. (maybe a blessing in disguise), and I have a few good ideas about where it is located and how to get there, but I can't seem to find a rock solid answer. 112" is a great answer, though. But is that at ride height? I don't know. I replied to an earlier post that the center of the wheel opening looks to be 18" from the C/L of the rear body mount, directly behind the axle...... FWIW, I guess.....

I can only imagine the ride you had when the axle fall off. I had a '62 Pontiac that the bushing pulled through the boss on the arm on one side when I was getting on it to pass someone and that was a butt clenching experience, to say the least. That was a while ago and I believe they used the top dr side / bottom pass side arm design. (Or vice / versa).

I agree on how to mount it (To the GM standard) and getting a trash car would be cool, but anyone I know within the state (junkyards / recyclers) doesn't have anything older than a '00. They seem to crush them as fast as they get them. Even the 'good 'ol boys' yards..... :angry:

Steve
 
Thanks all for the info and links. I'm going for the 112" WB measurement and go from there.

I'll keep you all updated and see where it ends up.

Steve
 
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