Charge Pressure Relief Settings that are Required with New 174-7572 Drive Axle {3278, 5117, 5117} Caterpillar

Asphalt Paver:

BG-210B (PIN: 9XJ1-278)

Introduction

This Special Instruction provides the information that is necessary in order to set the charge pressure relief setting of the propel pump and the flushing valve when the 174-7572 Drive Axle is used.

Setting the Charge Pressure Relief Setting of the Pump and the Flushing Valve

1. The charge pressure relief setting of the pump and the flushing valve needs to be increased for the proper release of the secondary brake on the axle. Adjust the charge pressure relief setting and the relief pressure of the flushing valve by using the following steps.
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   Illustration 1	g00674469
   (1) Flushing valve

   1. Completely turn in the set screw (1) for the flushing valve.
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   Illustration 2	g00674479
   (4) Case drain line on top of the propel pump

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   Illustration 3	g00674471
   (2) Charge pressure port

   2. The case drain pressure must be recorded. The following parts are needed in order to record the case drain pressure: 4C-4890 Hydraulic Test Group , 6V-4142 Fitting and 8T-0854 Pressure Gauge . Install the following components into the case drain line (4) that is on the top of the propel pump: 7D-0978 Tee , 5P-5005 Flared Reducer , 6V-3081 Hose Assembly , 6V-4144 Coupler that is from 4C-4890 Hydraulic Test Group , 6V-4142 Fitting and 8T-0854 Pressure Gauge . Add a 8T-0855 Pressure Gauge that is in the hydraulic test group to pressure port (2) .
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   Illustration 4	g00674478
   (3) Cartridge for charge relief valve

   3. Adjust the charge pressure by locating cartridge (3) on the bottom of the propel pump. Remove the cartridge and add 077-3775 Shim until the total stack of shims measures 5.84 mm (0.230 inch).

      Note: The cartridge originally has shims. The shims that are between the spring and the cap of the cartridge will need to be added into the total dimension of the stack.

      The dimension is only an approximation. The shim thickness may need to be adjusted again at a later time.

   4. Start and warm the machine up to operating temperature. Check the charge pressure when the engine RPM is set at approximately 2340 RPM and the propel lever is in the neutral position. Reference the pressure gauge for the case drain and subtract the gauge reading of the charge pressure. The charge pressure should be set at 2100 ± 70 kPa (305 ± 10 psi). If the pressure is not within this tolerance, you must add shims or you must subtract shims. A shim with a thickness of 0.010 inches will change the pressure by approximately 55 kPa (8 psi).

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Illustration 5	g00674469
(1) Flushing valve

2. The relief setting on the flushing valve (1) must now be adjusted to approximately 205 kPa (30 psi) below the charge pressure relief setting. The pressure setting is adjusted by noting the gauge reading for the charge pressure when the propel lever is moved from the neutral position to the forward position. The pressure will drop by 205 kPa (30 psi) when the pressure is set properly.