Steering Issues May Be Caused By the Shuttle Valve On Some Backhoe Loader Models{5264} Caterpillar

Backhoe Loader:

420E (S/N: HLS1-UP; KMW1-UP)

430E (S/N: DDT1-UP; EAT1-UP)

432E (S/N: BXE1-2200)

434E (S/N: FSH1-900)

442E (S/N: GKZ1-600)

444E (S/N: LBE1-600)

Introduction

The shuttle valve on the inlet manifold for the loader may come loose. The loose shuttle valve can cause the standby pressure to become high. The high standby pressure can cause steering issues.

Problem

Illustration 1	g01764094
(1) 227-1192 Valve Kit

Illustration 2	g01764095
(1) 227-1192 Valve Kit

The shuttle valve on the inlet manifold for the loader may come loose. The loose shuttle valve can cause the standby pressure to become high. The high standby pressure can cause steering issues. Thread lock has not been applied to the threads on the shuttle valve. This may cause the shuttle valve to come loose.

Solution

The pump standby pressure will need to be checked in order to verify proper operation of the inlet manifold.

1. Stop the engine. Release the pressure in the hydraulic system.

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Illustration 3	g01764295
(2) Port for the Pump discharge pressure

2. Attach one 177-7860 Hose As to the test port for the pump discharge pressure (2) .

3. Install an 8T-0860 Pressure Gauge with a range of 0 to 40,000 kPa (0 to 5800 psi) to the other end of the Hose Assembly.

4. Start the engine. Run the engine at 1200 RPM.

   Note: Do not move any hydraulic hand controls nor move the steering wheel while the 8T-0860 Pressure Gauge is installed. The higher pressure that is created by upstroking the pump can damage the gauge.

5. Read the pressure on the pressure gauge. The pressure should be 3350 ± 750 kPa (485 ± 109 psi).

   Note: If pump standby pressure is within the specification, the shuttle valve is operating correctly and no further work is required.

6. Run the engine at LOW idle. Stop the engine.

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Illustration 4	g01765513

7. When the pump standby pressure is higher than the specification, remove the hose at port (3) .

8. Remove the hydraulic connector at port (3) .

9. Very carefully check the 227-1192 Valve Kit (1) .

10. If the 227-1192 Valve Kit (1) came loose, check the upper guide section of the 227-1192 Valve Kit (1) and tighten to 21 ± 1 N·m (15 ± 1 lb ft).

11. Reinstall the ball for the shuttle check valve. Reinstall the seat for the shuttle check valve and tighten to a torque of 21 ± 1 N·m (15 ± 1 lb ft).

12. Repeat Step 1 through Step 6 in order to check if the pressure is within the specification.