Clean all components with clean solvent and dry with compressed air.
Check the spools for wear or scratches.
Check that the spools are not loose in their bore.
Check that the centering springs are not broken.
Check that the load check valve seats are not worn.
Check the load check poppets for damage.
Check the rubber boots and retainers.
Replace the parts as needed.
Use new O-rings and back-up rings.
Apply oil to all new O-rings and back-up rings before installation.
