Customer complained lift gradually lost hydraulics/lift; No pressure detected at control valve port. Rebuilt pump as a precaution (no defects noted) and disassembled, cleaned and resealed spool valve and main/tilt relief valves. Now, after pressure set, lifts fine and pressure is in spec. No action or pressure detected when tilt only engaged. Only when lift is locked at the top does the tilt engage. Pulled tilt relief and inspected; not defects noticed. Also, polished the poppets between the spools (FYI, this is a two spool valve only.) Any help appreciated.