Overview of Manual or Gas mechanism installation
Retrofitting (adapting) the mechanism
Start by positioning the replacement mechanism Pivot Pin 60% rearward of the front seat edge or roughly where the old mechanism pivot pin was located. The pivot pin usually can be seen from the underside of the mechanism. It is the only round steel rod going from one side of the mechanism to the other. The rod can be about 5/16" thick.
To avoid making repeated screwholes in the chair seat by trial and error mechanism placement, temporarily attach a 3/4" piece of plywood (our Mounting Board Kit) to where the old mechanism was bolted or screwed.
Test balance by first adjusting the chair height until the users legs are in a comfortable position, thighs parallel to the floor or slightly higher and feet flat on the floor. Clasp both hands behind your head. The chair should (or almost) begin to tilt rearward with this movement as your body weight shifts.
Should the chair tilt rearward too suddenly or too easily, move the mechanism to the rear about 2" and test again.
Should the chair be difficult to tilt back, move the mechanism forward towards the front seat edge by 2" and test again.
You may have to do either of the above mechanism movements more than once, reducing the amount of inch movement as you get close to the proper balance point. When proper balance is found, fine tuning if needed, can be achieved using the spring tension hand wheel (knob). After final placement, the plywood mounting board may be left in position or if preferred, removed and the mechanism then reattached directly to the seat bottom.