The Joy of a Simple Machine

My Superior IBA began pulsating on hp wax 2 days ago. I called my distributor and he gave me 2 things to check. One was the solenoid that controls the hp pump bypass valve (wax is actually 'medium pressure' and thus uses a bypass to cut pressure back a bit).

I looked at the solenoid and noticed the screw that holds the electrical body to the valve was missing! I guess the loose electrical bdoy was causing the valve to only open intermittently. Once the screw was replaced,the pulsation on 'wax' vanished.