To Service Timing Chain: Remove muffler and with a 1/2" impact wrench ,a 12" extension bar ,an angle drive and a shallow 35 or 36 mm socket, assess the pulley from beneath the facia. Rotate pulley keyway to 12' o'clock before removing pulley. Remove timing cover and adjust chain as per manual direction ( see below ).Removing the pulley nut will require 120# psi air pressure and several cycles of air tank pressure.Stay with the effort as it will come off. Replace the nut with the same pressure and hold for 20 seconds to tighten.In the event a shallow socket cannot be located, cutoff a long socket leaving 1/2" surface . Recommened reference: Volvo , 740 and 760, 1982-88, Automotive Repair Manual by Haynes # 97040 ; available at Autozone. [Non-text portions of this message have been removed]