Labrie EXPERT Maintenance Manual page 289

To prevent cavitation, air pressure inside the hydraulic tank must be set between 3 and 3.5 PSI. A
gauge and a pressure regulator (see Figure 5-22) are installed to adjust air pressure inside the tank.
This gauge is located inside the frame rail on the curbside of the chassis; it can be accessed only when
the body is raised.
Danger!
Install body safety prop before performing any work under the body.
To adjust the pressure, turn the knob until the pressure reaches 3 to 3.5 PSI. The hydraulic tank is
also equipped with a 5-PSI relief valve and a 5-PSI pressurized screw on the breather cap (see Figure
5-21).
Figure 5-21 5-PSI relief valve and breather cap
Figure 5-22 Pressure gauge and regulator
Caution!
The air pressure inside the tank shall not exceed 5 PSI.
Relief Breather
valve
Hydraulic System 279
cap
Pressure
regulator
Pressure
gauge