Hoelshcer 1000 accumulator

Recently purchased a used 575 baler hooked to the hoelshcer 1000. After changing all of the rotten hydraulic lines and realizing it had been hooked up to a closed center hydraulic tractor, redirected line for my open center kubota, I was ready to try it out but the lift arm won't return unless I pull on the all thread hooked to the shuttle valve which is spring return. Spring in valve seems weak. Thinking of adding a helper spring to assist in its resetting the lift arm. All experienced comments welcome.

Hoelshcer 1000 accumulator