Tools Required

Disassemble pressure relief valve.

Fig 1: Disassembling Pressure Relief Valve
Courtesy of GENERAL MOTORS CORP.
Remove gerotor cover and bolts.
Clean all parts in cleaning solvent. Remove varnish, sludge and dirt.

Fig 2: Removing Gerotor Cover And Bolts
Courtesy of GENERAL MOTORS CORP.
Inspect body clearance:
1. 4.1 Using a feeler gauge Service Tool SA 91101NE (or equivalent), measure the clearance between the driven rotor and pump body.
  Driven Rotor-to-Pump Body Side Clearance Standard: 0.150-0.277 mm (0.006-0.011 in.) Service Limit: 0.277 mm (0.011 in.) max.
2. 4.2 If the clearance is greater than maximum, replace the front cover assembly.
  
  Fig 3: Inspecting Body Clearance
  Courtesy of GENERAL MOTORS CORP.
Inspect tip clearance:
Using a Feeler Gauge Set SA91101NE (or equivalent), measure the clearance between both rotor tips.

Rotor Tip Clearance Service Limit: 0.150 mm (0.006 in.) max.

Fig 4: Measuring The Clearance Between Both Rotor Tips
Courtesy of GENERAL MOTORS CORP.
Inspect end-to-end clearance:
Using a Feeler Gauge Set SA91101NE (or equivalent) or Plastigage(R) (or equivalent) measure the clearance between the side of the gerotor assembly and the cover plate.

Rotor-to-Cover Side Clearance Standard: 0.040-0.125 mm (0.0016-0.0049 in.) Service Limit: 0.128 mm (0.005 in.) max.

Fig 5: Measure The Clearance Between The Side Of The Gerotor Assembly And The Cover Plate
Courtesy of GENERAL MOTORS CORP.