HYDRAULIC OIL FOAMING - TM-9-2320-285-24-20419

TM 9-2320-285-24-2

3-40. FIFTH WHEEL HYDRAULIC SYSTEM TROUBLESHOOTING (CONT)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

4. FIFTH WHEEL DOESN'T LOWER (Cont)

Step 5. Lower fifth wheel boom fully using bleed valve.

Remove hydraulic cylinder velocity fuses (para 2-78b(2)).

Try to raise and lower fifth wheel boom.

a. If fifth wheel boom lowers, velocity fuses are contaminated by foreign material; replace (para 2-

78b(2)).

b. If fifth wheel boom does not lower, hydraulic control valve is defective; repair or replace (para 3-42c).

5. HYDRAULIC OIL FOAMING

WARNING

Do not remove filler cap when hydraulic oil is hot. Hot oil can cause severe injury.

Remove hydraulic reservoir filler cap and check for proper viscosity hydraulic oil (compare thickness of oil

to that of oil from new container).

a. If oil from reservoir has the same consistency as sample oil, repair or replace hydraulic pump (para 3-

42a).

b. If oil from reservoir has different consistency than sample oil, drain and flush hydraulic system and

replace oil filters (para 2-78c and 2-78b(1)).

6. HYDRAULIC OIL OVERHEATING

Check hydraulic control valve relief pressure (para 3-42c).

a. If pressure is less than 2000 psi, adjust (para 3-42c). If pressure does not increase to 2000 psi, repair

or replace hydraulic control valve (para 3-42c).

b. If pressure is 2000 psi, refer to para 2-76, Malfunction 5, step 1.

3-413