ASSEMBLY - CONTINUED -832450288

TM 10-3930-660-24-2

PISTON PUMP MAINTENANCE - CONTINUED

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ASSEMBLY - CONTINUED

21.

With spacer (33) fully installed against bearing race (30), measure height of spacer with respect to the housing pintle

face using a micrometer. Take measurements in two places, 180 degrees apart.

22.

Average the two readings taken in step 23 above to

PINTLE

obtain a nominal value.

BEARING

SPACER

NOTE

A 0.007 to 0.009 in. (0.177 to 0.228 mm)

preload is required on the pintle bearings.

23.

Determine the number of shims required to obtain a

preload between 0.007 and 0.009 in. (0.177 to 0.228

mm) by subtracting the nominal preload (0.008 [0.203

mm]) from the calculated nominal valve (step 24).

PINTLE

FACE

409-1484

Example: Let's assume the depth readings were 0.029 and 0.027 in. (0.736 and 0.685 mm). Add these two figures

together and divide by two to obtain the average (nominal value):

0.029 + 0.027 = 0.056 in. (0.736 + 0.685 = 1.421 mm)

0.056/2 = 0.028 (1.421/2 = 0.710 mm) (nominal calculated valve)

Nominal Calculated Value - Nominal Preload Value = Required Shim Thickness

0.028 - 0.008 = 0.020 in. (0.711 - 0.203 = 0.508 mm) of shim thickness

NOTE

If calculated shim thickness is greater than 0.020 in. (0.508 mm), another shim must be added to the opposite

side of the yoke to reduce total shim thickness to less than 0.020 (0.508 mm). Shim thickness at either pintle

must not exceed 0.020 in. (0.508 mm). This is necessary to provide proper O-ring compression and prevent

pintle seal leakage.

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