Power Steering Vane Pump: Inspection

Fig 1: Measuring Oil Clearance Using Micrometer & Caliper Gauge

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

1. Standard clearance: 
   1. Front housing and shaft 0.020 - 0.077 mm (0.00079 - 0.00303 in.) 
   2. Rear housing and shaft 0.020 - 0.077 mm (0.00079 - 0.00303 in.) 

1. Maximum clearance: 
   1. Front housing and shaft 0.070 mm (0.00276 in.) 
   2. Rear housing and shaft 0.080 mm (0.00315 in.) 

If it is more than the maximum, replace a new vane pump assembly.

1. Using a micrometer, measure the height, thickness and length of the 10 plates.
   1. Minimum thickness: 1.405 mm (0.05531 in.) 
   Fig 2: Inspecting Vane Pump Rotor & Vane Plates

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2. Using a feeler gauge, measure the clearance between the rotor groove and plate.
   1. Maximum clearance: 0.03 mm (0.0012 in.) 

If it is more than the maximum, replace a new vane pump assembly.

Fig 3: Measuring Clearance Between Rotor Groove & Plate Using Feeler Gauge

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1. Coat the valve with power steering fluid and check that it falls smoothly into the valve hole by its own weight.
   Fig 4: Inspecting Flow Control Valve

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2. Check the flow control valve for leakage.

   Close one of the holes and apply compressed air 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.

If necessary, replace a new vane pump assembly.

Fig 5: Checking Flow Control Valve For Leakage

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Using calipers, measure the free length of the spring.

1. Minimum free length: 31.3 mm (1.2323 in.) 

If it is not within the specification, replace a new vane pump assembly.

Fig 6: Measuring Free Length Of Spring Using Calipers

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