Pressure Setting Procedure; Main System Relief; Steer Left Relief - JLG 400S Service And Maintenance Manual

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5.4 PRESSURE SETTING PROCEDURE

Cold temperatures have a significant impact on pressure read-

ings. JLG Industries Inc. recommends operating the machine

until the hydraulic system has warmed to normal operating

temperatures prior to checking pressures. JLG Industries Inc.

also recommends the use of a calibrated gauge. Pressure read-

ings are acceptable if they are within ± 5% of specified pres-

To ensure all pressures are set correctly, the following proce-

dures must be followed.

1. Install a pressure gauge at MP1 port of the Main Control

Valve capable of reading pressures up to 4000 psi

2. Activate telescope in function continuously

at end of stroke. Observed pressure should

be 3000 ± 75 psi (207 ± 6 Bar).

SECTION 5 - BASIC HYDRAULICS INFORMATION & SCHEMATICS

3. If necessary, loosen jam nut and adjust the Main System

Relief valve clockwise to increase and counter-clockwise

to decrease.

1. Install a pressure gauge at port MP1 of the Main Control

Valve capable of reading pressures up to 4000 psi

2. Activate Steer Left function

continuously at end of stroke.

Observed pressure should be

2750 ± 75 psi (190 ± 6 Bar).