TM 5-2420-231-23-1
0073
Table 1. Multiple Backhoe Operations (Pilot Controls) Do Not Function Correctly - Continued.
073
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Test Step 25. Test Pump Efficiency.
Multiple Backhoe
Operations (Pilot Controls)
1. Perform large hydraulic oil pump
Pump Efficiency 70 Percent or
Do Not Function Correctly -
efficiency reading (WP 0086).
Greater - Proceed to step 2.
Continued
Pump Efficiency Less Than 70
Percent - Perform Flowmeter
Disconnect Procedure (WP 0086).
Replace hydraulic oil pump (WP 0230).
Proceed to Test Step 29.
2. Perform large and small hydraulic
Pump Efficiency Greater Than 70
oil pump efficiency reading
Percent - Perform Flowmeter
Disconnect Procedure (WP 0086).
Proceed to Test Step 26.
Pump Efficiency Less Than 70
Percent - Perform Flowmeter
Disconnect Procedure (WP 0086).
Replace hydraulic pump (WP 0230).
Proceed to Test Step 29.
Test Step 26. Test for Faulty Pattern
Change Solenoid Valve 1.
1. Turn ignition switch to the off posi-
tion (TM 5-2420-231-10) and dis-
connect batteries (WP 0157).
2. Disconnect pilot control wiring har-
ness connector (WP 0007, Figure
191) from pattern change solenoid
valve 1 (WP 0007, Figure 192).
3. Connect batteries (WP 0157) and
turn ignition switch to the on posi-
tion (TM 5-2420-231-10).
4. Turn pilot control switch to on posi-
tion (TM 5-2420-231-10).
5. Using a digital multimeter, mea-
Voltage 10 to 14 Volts - Proceed to
sure voltage between pilot control
Test Step 27.
wiring harness connector (WP
Voltage Less Than 10 Volts - Replace
0007, Figure 191) terminals 1 and
pilot controls wiring harness (WP 0187).
2. Voltage should be 10 to 14 volts.
Proceed to Test Step 29.
Test Step 27. Test for Faulty Pattern
Change Solenoid Valve 2.
1. Turn ignition switch to the off posi-
tion (TM 5-2420-231-10) and dis-
connect batteries (WP 0157).
2. Disconnect pilot control wiring har-
ness connector (WP 0007, Figure
193) from pattern change solenoid
valve 2 (WP 0007, Figure 194).
0073-13