So my seats have been driving me insane.

I have restored them, and love having the original look seats in it, but have had issues with the mechanism. The locking side is just fine, and holds well, but the sprung side is way, way too loose, and sags such that my back starts to hurt if i don't put something behind it to keep it from sagging back.

What, if anything, can be done about this. I have thought of putting locking mechanisms on both sides, but don't know what others have done to refurbish this, and would love some suggestions.

Thank you all.

i'm not sure from your post exactly what is "sagging" - when i refurbished my seats, i noticed that if the two bolts that hold the hinges to the sides of the seat pan and seat back were not fully torqued and centered that the small amount of play created quite a bit of slack on the seat back. you might want to check that these bolts (4 per side of each seat) are good and snug. the ones on the seat back are large Phillips head and mine were pretty messed up so i replaced them w/some SST countersunk allen head fasteners that fit beautifully and look factory (if you didn't know) the plus being that you can torque them fully vs. dealing w/the Phillips heads...

when i sit in the seat, the side that does not have the locking mechanism leans back, while the other side is locked in place, and not moving.

They are very much snug and are not the issue. Its the spring/mechanism itself that is allowing it to move.

hmmm... sounds like something's broken - iirc, the seat shouldn't allow that much twist. did you see any structural damage when you had them apart? the seat back should stay rigid enough to hold itself straight. maybe a cracked weld on the mechanism side?

seems more like the spring mechanism that is on the non locking side is given up.

Just wondering if anyone has had this happen, and or what can be done to fix it. Like i said, i might try putting locking on both sides.

There are no springs on either side of the seats for the early cars. One side has the rake adjustment knob with its gear and cam mechanism; the other side has only a pivot point. As pointed out above, if the large Phillips-head screws have come loose it is likely the holes in the seat frames are wallowed out and allowing for movement. Another possibility is that the pivot point on the non-adjusting side is damaged. Pulling the seats out and inspecting the hinges is the only way you'll answer the question.