Power Steering Vane Pump: Inspection

Using a micrometer and caliper gauge, measure the oil clearance.

Fig 1: Identifying Micrometer, Caliper & Vane Pump Shaft & Bushing Measurement Points

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

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

Fig 2: Measuring Vane Plates

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1. Using a micrometer, measure the height, thickness and length of the vane plates.

   Minimum height: 8.6 mm (0.339 in.).

   Minimum thickness: 1.397 mm (0.0550 in.).

   Minimum length: 14.991 mm (0.5902 in.).

NOTE: There are 5 vane plate lengths with the following vane pump rotor and cam ring marks:
Fig 3: Rotor & Cam Ring Identification/Specifications
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Fig 4: Measuring Rotor Groove & Plate Clearance
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Fig 5: Locating Rotor & Cam Ring marks
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2. Using a feeler gauge, measure the clearance between the vane pump rotor groove and vane plate.

   Maximum clearance: 0.035 mm (0.0014 in.).

   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.

   Inscribed mark: 1, 2, 3, 4 or None.

1. Coat the flow control valve with power steering fluid and check that it falls smoothly into the flow control valve hole by its own weight.
   Fig 6: Inspecting Flow Control Valve

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2. Check the flow control valve for leakage. Close one of the holes and apply 392-490 kPa (4-5 kgf/cm2, 57-71 psi) of compressed air into the opposite side hole, and confirm that air does not come out from the end holes.
   Fig 7: Testing Flow Control Valve

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   If necessary, replace the flow control valve with the one having the same letter as inscribed on the front housing.

   Inscribed Mark: A, B, C, D, E or F.

   Fig 8: Locating Flow Control Valve Marks

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Using vernier calipers, measure the free length of the spring.

Fig 9: Measuring Flow Control Valve Spring Length

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Minimum free length: 32.3 mm (1.272 in.).

If it is not within the specification, replace the spring.