Adjustable spring plates only adjust 1 way
 

I got some Rennline adjustable spring plates from our host for my '74. They are the type that have a cam bolt. Upon installing them, they freely adjust in the direction that would lower the car. But in trying to turn the cam in the opposite direction, I encounter strong resistance. I cannot get the plates to move in the direction that would raise the car. The plates are not connected to the control arm. The adjustment is in the center of its range. Anybody know what's going on?

Depending on what side you are on and the position of the cam you can end up in a situation where rotating the cam to move the spring plate will tighten the nut against the lock washer on the other side. So, Loosen the jam nut and see if the resistance is reduced.

Thanks for the reply, but it's the same situation both sides and the jam nut is loose.

Never used the Rennline products. Take them off the car, pull the adjuster and fixing bolts and see if the inner/outer plates are binding. Then go from there.