Power Steering Vane Pump: Inspection

Measure oil clearance between vane pump shaft and bushing.
1. Using a micrometer and a caliper gauge, measure the oil clearance.
  1. Standard clearance: 0.016-0.040 mm (0.0006-0.0016 in.)
  2. Maximum clearance: 0.07 mm (0.0028 in.)
  If it is more than the maximum, replace the front housing and vane pump shaft.
Inspect vane pump rotor and vane plates.
1. Using a micrometer, measure the height, thickness and length of the 10 vane plates.
  
  Fig 2: Measuring Dimensions Of Vane Plates
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. Minimum height: 7.6 mm (0.299 in.)
  2. Minimum thickness: 1.405 mm (0.0553 in.)
  3. Minimum length: 11.993 mm (0.4722 in.)
2. Using a feeler gauge, measure the clearance between the vane pump rotor groove and vane plate.
  
  Fig 3: Measuring Clearance Between Vane Groove & Vane Plate
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. Maximum clearance: 0.03 mm (0.0012 in.)
  2. If it is more than the maximum, replace the vane plate and/or vane pump rotor with the one having the same mark stamped on the cam ring.
    
    Fig 4: Identifying Inscribed Marks On Vane Pump Rotor & Cam Ring
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    Inscribed mark: 0, 1, 2, 3, or 4
    
    NOTE: There are 5 vane plate lengths corresponding to the following vane pump rotor and cam ring marks in Fig 5
    
    Fig 5: Displaying Vane Pump Rotor & Cam Ring Attributes
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Inspect flow control valve.
1. Coat the flow control valve with power steering fluid and check that it falls smoothly into the valve hole of the front housing by its own weight.
  
  Fig 6: Checking Flow Control Valve Operation
  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 hole.
  
  Fig 7: Checking Flow Control Valve For Leaks
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. If necessary, replace the flow control valve with the one having the same letter as inscribed on the front housing.
    
    Fig 8: Locating Inscribed Markings On Front Housing & Flow Control Valve
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    Inscribed mark: A, B, C, D, E or F
Inspect spring.
1. Using vernier calipers, measure the free length of the spring.
  
  Fig 9: Measuring Free Length Of Spring
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Minimum free length: 36.9 mm (1.453 in.)
2. If it is not within the specification, replace the spring.