FOG OIL PUMP ASSEMBLY PRESSURE RELIEF VALVE ADJUSTMENT.

3-1040-279-12&P

4-31 FOG OIL PUMP ASSEMBLY PRESSURE RELIEF VALVE ADJUSTMENT.

This task covers adjustment of Fog Oil Pump Assembly Pressure Relief Valve.

INITIAL SETUP

Tools

General Safety Instructions

General Mechanic's Automotive Tool Kit

Fog oil is very slippery. Clean up all spills

SC 5180-90-CL-N26

immediately to prevent injury to personnel.

Test Equipment

Equipment Condition

Vehicle engine running.

Fog oil test gage (Fig. G-21, App G)

ADJUSTMENT

NOTE

There are two pressure relief valves. The pro-

cedures are the same for both pressure relief

valves.

1. Remove fog oil hose from fog oil disconnect (1).

2. Remove pipe plug from tee (4) and install test gage (Fig G-21, App G). Make sure valve on

gage is closed (lever to the side).

3. Set OIL switch on terminal bracket assembly to ON. See P. 4-96 for location. On M1059

vehicles, it may be necessary to lower inboard armor shield and remove smoke generator.

4. Set circuit breaker CB1 and POWER switch to ON. Ensure vehicle engine is running. Turn FOG

OIL FLOW control knob fully clockwise.

NOTE

Have a container available to collect fog oil

or drain fog oil back into tank during next

step.

5. Set FOG OIL switch to RUN position and observe reading on test gage. Fog oil pressure should

be 25 psig for operating temperatures of 90F and above or 55 psig for temperatures below

90F. If not, bleed air from pump and hoses by opening valve on test gage assembly until fog

oil runs out. Close valve and observe gage. If correct pressure is still not obtained, adjust pressure

relief valve as follows.

6. Loosen locknut (2) securing adjuster (3) of fog oil pressure relief valve.

7. Turn adjuster clockwise to increase pressure, turn adjuster counterclockwise to reduce pressure.

8. When correct pressure is obtained, tighten locknut (2)

to secure adjuster (3).

9. Set FOG OIL switch, POWER switch, and circuit breaker

CB1 to OFF, and turn FOG OIL FLOW control knob

fully counterclockwise.

10. Set OIL switch on terminal bracket assembly to OFF.

11. Disconnect test gage and reinstall pipe plug in tee (4) and

fog oil hose on fog oil disconnect (1).

Change 2