Challenger 35, Challenger 45 and Challenger 55 Agricultural Tractors Implement, Steering and Brake Hydraulic Systems Caterpillar

Illustration 1	g00574292
(1) Primary resolver (2) Secondary resolver (3) Passage to compensator valve (A) Three-point hitch control valve (B) #4 implement control valve (C) #3 implement control valve (D) #2 implement control valve (E) #1 implement control valve

Primary resolvers (1) and secondary resolvers (2) are check valves. These resolvers compare two pressures. The lower pressure is blocked. The higher pressure flows to the next component in the resolver network. This higher pressure is called the load sensing signal.

Each implement control valve has two resolver valves.

Primary resolver (1) compares the pressure at the head end and the rod end of the hydraulic cylinder.

Secondary resolver (2) compares the pressure from the primary resolver in the control valve to the signal from the upstream control valves. The secondary resolvers are arranged in series.

The highest resolved pressure from the secondary resolvers flows to the compensator valve for the implement hydraulic pump through passage (3) .

Perform the following steps in order to check the resolver network:

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Illustration 2	g00535727
Connector with orifice check valve

1. Disconnect the load sensing line from the connector on the inlet manifold.

   1. Verify that the orifice check valve that is located in the connector is functioning properly.

   2. If the orifice check valve is functioning properly, proceed to Step 2.

   3. If the orifice check valve is not functioning properly, replace the connector. Verify if the implement control valves are functioning properly.

2. Start the engine.

3. Warm the hydraulic oil to 60°C (140°F).

4. Run the engine at high idle.

5. Operate the control valves in the following order:

   1. Operate #1 implement control valve (E) .

   2. Operate #2 implement control valve (D) .

   3. Operate #3 implement control valve (C) .

   4. Operate #4 implement control valve (B) .

   5. Operate three-point hitch control valve (A) .

6. Use the test that is indicated for the following conditions.
   • If the #4 implement control valve malfunctions or the three-point hitch control valve malfunctions, refer to "The #4 Implement Control Valve Malfunctions or The Three-point Hitch Control Valve Malfunctions".

   • If the #1, the #2, or the #3 implement control valves malfunction, refer to "The #1, The #2, or The #3 Implement Control Valve Malfunctions".

   • If more than one of the control valves malfunction, refer to "More Than One Control Valve Malfunctions".

The #4 Implement Control Valve Malfunctions or The Three-point Hitch Control Valve Malfunctions

Illustration 3	g00574333
(1) Primary resolver (2) Secondary resolver (A) Three-point hitch control valve (B) #4 implement control valve (C) #3 implement control valve (D) #2 implement control valve (E) #1 implement control valve

1. Stall #1 implement control valve (E) .

   1. This will supply pressure oil to the entire system.

2. Operate the malfunctioning control valve.

   1. If the malfunctioning control valve operates during the stall of #1 implement control valve (E), the secondary resolver in the malfunctioning control valve is faulty.

   2. If the malfunctioning control valve does not operate correctly during the stall of #1 implement control valve (E), there may be a problem with the primary resolver.

The #1, The #2, or The #3 Implement Control Valve Malfunctions

Illustration 4	g00574334
(1) Primary resolver (2) Secondary resolver (A) Three-point hitch control valve (B) #4 implement control valve (C) #3 implement control valve (D) #2 implement control valve (E) #1 implement control valve

1. Stall the #4 implement control valve.

   1. This causes the secondary resolver in the malfunctioning control valve to separate the primary resolver in the malfunctioning control valve from the signal passage.

2. Operate the malfunctioning implement control valve.

   1. If the malfunctioning implement control valve operates during the stall of the #4 implement control valve, the secondary resolver in the malfunctioning implement control valve is faulty.

   2. If the malfunctioning implement control valve does not operate correctly during the stall of the #4 implement control valve, there may be a problem with the primary resolver.

More Than One Control Valve Malfunctions

Illustration 5	g00574336
(1) Primary resolver (2) Secondary resolver (3) Passage to compensator valve (A) Three-point hitch control valve (B) #4 implement control valve (C) #3 implement control valve (D) #2 implement control valve (E) #1 implement control valve

Perform this check if two or more valves that are in series do not operate correctly.

1. Operate the malfunctioning control valve that is farthest away from passage (3). Continue to operate this control valve throughout the test.

   1. For example, if the #3, the #4 implement control valves and the three-point hitch control valve are malfunctioning, operate the three-point hitch control valve.

2. In sequence, operate the remaining implement control valves that were malfunctioning.

3. Operating one of these control valves should cause both control valves to operate correctly. This control valve has a faulty secondary resolver.