The Hydraulic Float Function For the Three-Point Hitch is Causing Poor Actuation.{5051, 5702, 5705} Caterpillar

Backhoe Loader:

414E (S/N: ELB1-UP)

Introduction

The problem that is identified below does not have a known permanent solution. Until the permanent solution is known, use the solution that is identified below.

Problem

Reference Refer to Operations and Maintenance Manual, SEBU8289, "Three-Point Hitch Control".

Some machines may require an adjustment of the hydraulic oil flow to the three-point hitch. The adjustment will control the speed of the rear implements. The adjustment will also improve the float function. This fine adjustment is only permissible if the machine is equipped with an adjustable 285-1188 Electrohydraulic Control Gp .

Solution

Adjustment Procedure

Illustration 1	g01372947
(A) New Joystick (B) Former Joystick (1) Lift Function (2) No Function (3) Tilt Function (4) Pitch Function

Illustration 1 shows the difference between the joysticks. The new joystick (A) can be identified by the nine trim potentiometers for the adjustment of hydraulic flow. The former model (B) does not have the feature for the adjustment of flow.

Illustration 2	g01373130
(A) New Joystick (4) Auxiliary (5) Pitch Forward (6) Pitch Backward (7) Raise (8) Lower (9) Float (10) Tilt Left (11) Tilt Right (12) Auxiliary

The new joystick has four trim potentiometers on one side that control the following functions: (4) auxiliary, (12) auxiliary, (11) tilt right and (10) tilt left. The five trim potentiometer on the opposite side of the joystick control the following functions: (5) pitch forward, (6) pitch backward, (7) raise, (8) lower and (9) float. Auxiliary function (4) and auxiliary function (12) are not proportional. Auxiliary function (4) and auxiliary function (12) cannot be adjusted at the joystick's trim potentiometers.

Show/hide table



Illustration 3	g01372859
(C) 285-1187 Bank Valve Gp (1a) Hose for lift lower function (1b) Hose for lift lower function

1. Interchange the hoses for the lift lower function on the 285-1187 Bank Valve Gp . Switch hose (1a) with the hose (1b) .

Show/hide table



Illustration 4	g01395827
(A) New Joystick (1) Lift Function

2. Flip the lift switch to the opposite side.

Show/hide table



Illustration 5	g01373296
(A) New Joystick (7) Adjustment for raise (9) Adjustment for float

3. Turn the trim potentiometer (7) for "float" counterclockwise until the screw stops.

4. Turn the trim potentiometer (9) for "raise" counterclockwise 3.2 mm (0.125 inch) of a turn.

5. Reinstall the joystick.

6. Start the engine and run the engine for a couple of minutes.

7. Ensure that all of the Joystick's control functions work properly.

8. Pull the lever of the Joystick control fully backward.

   Note: The float switch must not be turned on during this procedure.

   The float function should not actuate during step 8. Return to step 4 and readjust the trim potentiometer if the float function actuates.

Illustration 6	g01373726
(C) 285-1187 Bank Valve Gp (13) Auxiliary (14) Pitch (15) Tilt (16) Lift (17) Auxiliary Adjustment Screws

Auxiliary functions are not proportional.

Flow for the auxiliary function can be adjusted only by the valve screws (17) on the 285-1187 Bank Valve Gp (C) .