BACKHOE BOOM CYLINDER DOES NOT WORK

TM 5-2420-222-20-1

ORGANIZATIONAL TROUBLESHOOTING - CONTINUED

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

16. BACKHOE BOOM CYLINDER DOES NOT WORK

Step 1.

Check backhoe control valve-to-backhoe boom cylinder oil lines (1 thru 4) for sharp bends, dents, or

kinks.

a. If backhoe control valve-to-backhoe boom cylinder oil lines (1 thru 4) are not bent, dented, or

kinked, go to step 2.

b. If manifold block-to-head end boom cylinder oil line (1) has sharp bend, dent, or kink, replace

(page 2-1565).

c. If manifold block-to-rod end boom cylinder oil line (2) has sharp bend, dent, or kink, notify Direct

Support Maintenance.

d. If backhoe control valve-to-manifold block oil lines (3 or 4) has a sharp bend, dent, or kink,

replace (page 2-1558).

WARNING

Keep clear of area between main frame and backhoe boom, and other backhoe components, when backhoe

control levers are being operated. There is no clearance for personnel when boom is swung full-left or full-right.

Step 2.

Connect hydraulic system test set in backhoe control valve-to-manifold block oil line (3 or 4)

between backhoe control valve (5) and manifold block (6). Have assistant start and run engine at

1,250 rpm (TM 5-2420-222-10). While assistant operates backhoe boom control lever (7), note

reading on hydraulic system test set. Pressure gage reading should be 1700 to 1800 psi (11,645 to

12,411 kPa). Shut down engine (TM 5-2420-222-10) and disconnect hydraulic system test set.

a. If hydraulic system test set pressure gage reads 1700 to 1800 psi (11,645 thru 12,411 kPa),

notify Direct Support Maintenance.

b. If hydraulic system test set pressure gage reads less than 1700 psi (11,645 kPa), replace

backhoe control valve (page 2-1260).

17. BACKHOE BUCKET CYLINDER DOES NOT WORK

Step 1.

Check backhoe control valve-to-backhoe bucket cylinder oil lines (8 thru 11) for sharp bends, dents,

or kinks.

a. If backhoe control valve-to-backhoe bucket cylinder oil lines (8 thru 11) are not bent, dented, or

kinked, go to step 2.

2-124