Hi G,
The 'flanges' on the liners DO need to be trimmed off in the center so that the spring leafs alone are in the space between the front and back bolts.

cwl's suggestion seems like a good solution for your situation.

There IS something else going on with the spring though because typically the spring can be bolted to the differential without needing a jack to put some pressure on the leafs.
I just did this a couple of days ago.
Regards,
Alan

Note there's still some arch in the center of the spring because the 4 mounting bolts won't be torqued until the weight of the car is on the spring.

 

Thanks Alan,
I will do the trimming, did a little already. Then try to install the spring. Thanks to everyone for all the input. I'll update how it goes.

 

the guys replacement sure is thick and
the interleaves thick.
gonna take some time and measurement on length.
i agree a stock spring like pictured takes work out of it.
i am not there.
i do know i have had to "walk" in a spring
these springs hold a lot of weight

 

it is getting so i can't remember certain stuff
seems this plastic type leaves have been discussed.
from anti sqeak to slides on itself better than stock.
anyway. be very careful
take time to think it thru.
i am worried for you.
final compression is my big thing.
good luck

 

Ya, I am too. We came up with a three jack scenario to get it in....we thought better of it and decided to reach out here.

 

Don't overlook this issue once you do get it in....I'm not sure how much torque I put on those bolts before putting any weight on it...Not much more than 20 or 30 foot lbs.....I know once it was back on the ground the bolts were not even finger tight...I think 70 foot lbs is correct after it has full weight on it.

Good luck
Brian

 

Hi Brian,
"I think 70 foot lbs is correct after it has full weight on it."
You're thinking right.
The Rear Suspension section of the AIM indicates 60-80 lbs.ft. with a note indicating to torque the 4 bolts AFTER the spring has been loaded to design height.
Regards,
Alan

These are midyear chassis but I think the chassis for 68+ cars were assembled in the same way in the basement level of the St.Louis plant. The rear spring isn't loaded.
Note too that the frame has been measured and the shim count is on the frame long before the body is dropped on the frame.

 

FOR WHAT THIS IS WORTH.

Due to you not having the original spring to compare to this is SIMPLE to figure out.

Take the bolts you have an thread then into the rear end cover. You might want to run a tap into the holes first to make sure they are clean and NOT making you think that you have bottomed them out...when actually.... you have more room to thread the bolt into the rear end cover.

When you have the bolt in all the way and LIGHTLY SNUG it and oyu know it is in as far as it can go. Mark the bolt in some way. I usually use some of my vinyl masking tape and wrap it around the bolt thread where it meets the machined flat surface of the rear end cover.

Take the bolts out and compare them. Make sure you use the SHORTEST amount of thread that went into the hole.

Knowing that this is the amount of thread that you know you CAN NOT EXCEED.

It is now up to your math skills.

Knowing how thick the spring is. And measure it at the center bolt where all the leaves are held together. 'Thinking' that these four bolts are going to compress this spring further has no merit. Thinking that the weight of the car is also going to smash the leaves closer together to the point where it is a concern is another misconception.

SO...taking into account the thickness of your split lock washer...and the thickness of the plate that the four bolts go through and the thickness of the spring. You will know how long the bolt will be up to the point of the flat machined surface of the rear end cover.

THEN...knowing how many threads the bolt went into the rear end cover is another measurement.

Calculate these numbers and make the bolt slightly SHORTER than what you know it needs to be.

If the original bolts has witness marks and shows actually how many threads GM allowed to go into the rear end cover...you want to try to duplicate that...BUT...if you find that the bolt can be a tab bit longer and still NOT cause for any concern...make the bolt longer when you cut it.

And ...keep this in mind.....getting longer bolts so you can at least get the spring held in place....use them. Because when you get the long bolts installed at the end of the spring...MAKING SURE YOU DO ONE AT A TIME!!!! and the car is back on the ground....and the spring flattens out....you can remove the bolts and put in the ones you made. Because the spring is NOT going to go anywhere if the car is on the ground and you do one bolt at a time.

I believe the bolt should be a 7/16-13 thread.

DO NOT APPLY grease or anything on the threads of these bolts!!!!!!!!! Install them and torque them DRY!!!!!!!!!

I have had to do this more times than I care to count..and this never has caused me any problems.

DUB

 

DUB,
Thanks for that. That was basically what I thought,but I didn't think to check all four bolt holes. I was just going to do one. Excellent advice.

 

NO NEED to check the outer holes because they are tapped all the way through and can not do any damage to the gear oil portion of the rear end cover.

The outer bolts/holes can snap and break off IF the spring is not FLAT when you go to torque the bolts.

I would still run a tap though the outer holes.

DUB

 

I was able to get the spring mounted today, by myself! The walking it in by attaching one side then jacking up the spring and putting the other two bolts in worked out great. Thanks to everyone for the help!!