Slight droop in rear spring.
 

I had the 4:11's removed and 3:55's installed in my rear end.

When I got it home I reinstalled everything and I noticed a slight droop in my drivers side.

The springs and spring height have always been perfect.

Could I have installed something wrong?

Can a rear spring be installed incorrectly?

Any advise welcome.

Note: If it matters. The car is a 65 GTO.

Two pictures included

I was looking at the rear of my TA one day and noticed the same thing. Got a tape measure and sure enough, one side was about a half to ¾” lower. Opened up the trunk and noticed my tool box and the rest of my junk had all shifted or been moved to one side. I rearranged it, re-measured and it was spot on even.

Something to check, the junk in your trunk…

I had the same issue after installing a set of lowering coils in my 71. A full tank of gas, two people in the rear seat the rear end was very low. Not to mention the same issue of the drivers side rear bumper being lower than the passenger side. I bit the bullet and purchased a set of Air-Lift bags to go inside the springs, problem solved. I usually only run about 5 - 7 psi. This will let you even things out and not worry when you have heavier than usual loads.

Loosen all of the control arm bolts then with the car on the ground jounce the car then retighten the bolts. Might have a bushing that was tightened and under load if the rear end was tightened with the axle hanging down. :)

I did replace all those bushings then.

Thanks, I will try it.

I couldn't find a free 1965 service manual online but this is from a 1968 where it states the rear springs have to be install in a specific orientation.

INSTALLATION
Install spring, making sure that the end of the
bottom coil is positioned between the limits of the
two holes located at the rear of the spring bracket
on axle housing.