I'm in the process of a frame-off on my 68 coupe. I'm starting to put it back together and I'm having problems installing the rear leaf spring. When I jack the spring up to align with trailing arm bolt, the entire frame rises up. Since the body is off the frame including engine and trans. there is not enough weight to hold the frame down. Any tricks on getting this done? I have tried tying a rope around the spring and placing a bottle jack on top of the frame and then jacking it up. My rope stretches and I'm unable to get it done. Thanks in advance.

 

Hi 68 bb,
This is a situation my folks find themselves in while putting the running gear back on the frame when the body isn't back in place yet.

I find one solution is to add weight to the rear of the frame to prevent it from rising as the jack is pumped up. Folks use whatever they have handy as 'ballast'.
I used some bundles of roofing shingles and boxes of old car magazines.

It's a good idea to clamp a block of wood to the SPRING to prevent the JACK from sliding towards the center of the spring as it's being raised.

This method is actually described in the Chassis Service Manual although it uses some nice equipment that actual mechanics typically have.

You still need to be careful because there's a LOT tension in the spring as you raise it.

Good Luck!
Regards,
Alan

 

Any idea of how much weight is needed? I thought about having my 150 lb son sit on the rear while I jack up the spring but I'm thinking it will require more weight.

[QUOTE=Alan 71;1595658448]Hi 68 bb,
This is a situation my folks find themselves in while putting the running gear back on the frame when the body isn't back in place yet.

I find one solution is to add weight to the rear of the frame to prevent it from rising as the jack is pumped up. Folks use whatever they have handy as 'ballast'.
I used some bundles of roofing shingles and boxes of old car magazines.

 

Hi 68,
I'm thinking I had about 350-400 lbs. of weight on the back of the frame.
As you begin raise the floor jack you'll know immediately when you don't have enough weight.
Regards,
Alan

 

I have not reached this point yet but I recall seeing another member's post where he used wood posts running from top of frame up to ceiling of garage to prevent the frame from rising. Wish I could remember who it was so you could see the pics. I just made a mental note of it knowing I would need to deal with this at some point. Good luck!

 

I think I'm going to try that technique. I'll let you know how it works!

 

We just put our rear together, but the body is on. What I did want to mention, is something I read somewhere, I believe, from Willcox Corvette. It said do NOT tighten the bolts where the spring fastens to the rear differential until the car is on the ground & under load, or the rear diff WILL break. I don`t know if anybody else has heard of this or not, but it sounds like the "voice of experience", and we left ours a little loose until we set it back down off the jack stands. Any other comments or input on this issue?

 

Hi GTO,
That information is found in the Rear Suspension Section of the AIM.

"Bolts must be torqued with spring compressed to design height".

The same type of note is found in the Front Suspension Section concerning the bolts that load the a-arm bushings.
Regards,
Alan

I'm wondering if there was a way to load the suspension while the chassis' was being assembled?

 

I saw a post several years ago on this subject. The guy used a HD ratchet strap from the spring end to the frame and essentially pulled the spring up into place. A come-along might work also.

 

 

I do believe that is the pic I remembered!