Power Steering Vane Pump Inspection

WARNING: This page is about a different car, the 2002 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.

Check oil clearance between vane pump shaft and bushing .
Using a micrometer and caliper gauge, measure the oil clearance.

Standard clearance: 0.03 - 0.05 mm (0.0012 - 0.0020 in.) .

Maximum clearance: 0.07 mm (0.0028 in.) .

If it is more than the maximum, replace the shaft and front housing.

Fig 1: Identifying Micrometer, Caliper & Vane Pump Shaft & Bushing Measurement Points
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Inspect vane pump rotor and vane plates .
1. Using a micrometer, measure the height, thickness and length of the 10 plates.
  
  Fig 2: Measuring Vane Plates
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Minimum height: 8.6 mm (0.339 in.) .
  
  Minimum thickness: 1.397 mm (0.0550 in.) .
  
  Minimum length: 14.991 mm (0.5902 in.) .
2. Using a feeler gauge, measure the clearance between the rotor groove and plate.
  Maximum clearance: 0.033 mm (0.0013 in.)
  
  If it is more than the maximum, replace the plate and/or rotor with one having the same mark stamped on the cam ring.
Inspect flow control valve .
1. Coat the flow control valve with power steering fluid and check that it falls smoothly into the valve hole by its own weight.
  
  Fig 6: Inspecting Flow Control Valve
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check the flow control valve for leakage. Close one of the holes and apply compressed air of 392-490 kPa (4-5 kgf/cm² , 57-71 psi) into the opposite side hole, and confirm that air does not come out from the end holes.
  
  Fig 7: Testing Flow Control Valve
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
If necessary, replace the flow control valve with one having the same letter as inscribed on the front housing.

Fig 8: Locating Flow Control Valve Marks
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Inscribed mark: A, B, C, D, E or F
Inspect spring .
Using vernier calipers, measure the free length of the spring.

Fig 9: Measuring Flow Control Valve Spring Length
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Minimum free length: 33.2 mm (1.307 in.)

If it is not within specification, replace the spring.