Cat works for 2 days. It only vibrates on the left piston. Pistons are single stage. I will cheak the air. No vibration at high speed. It does vibrate on insp. It does get smoother toward the bottom of the hoistway. The job is six years old installed by mitsu.... We changed the packing its the right size. Butcher has 1 ring yellow packing w/ a black nylon ring on the inside of the ring, weird. I am kinda thinking building compression, and movement, jacks ar'nt plumb?
