Table 4-2. Unit Troubleshooting-continued -706880179

TM 5-4210-233-14&P-1

Table 4-2. Unit Troubleshooting - Continued

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

AXLES - Continued

AXLE DOES NOT ENGAGE DIFFERENTIAL LOCK-UP

Step 1. Check for broken or pinched air line.

Check and replace air line (see para 4-9).

Step 2. Check if lock-up air chamber diaphragm is broken or chamber has internal damage.

Replace air chamber. Notify Direct Support.

Step 3. Air switch defective.

Replace switch. Notify Direct Support.

FIREFIGHTING SYSTEM

PUMP FAILS TO PRIME OR LOSES PRIME

NOTE

Some pump operators mistakenly assume that the main pump is

fully primed when they see the first discharge of water and oil

come out of the priming pump discharge pipe, or when they see

a slight pressure on pressure gauge. Operate pump until it

emits a solid stream of water through its discharge pipe.

NOTE

If desired, the pump may be running while priming. However,

priming may be more positive if the impellers are stationary.

NOTE

At temperatures of 0 deg. F (-18'C) or below, use SAE 5W or

5W-20 engine oil in priming tank. Heavier oils are not suitable

at low temperatures.

Step 1. Battery has low state of charge.

Make sure battery is properly charged. If battery is in low state of charge, it may be difficult

to operate the priming pump at proper speed.

4-50