Pressure Bleeding Procedure; Bleeding Schematic - JLG GRADALL 522D Owner's/Operator's Manual

PRESSURE BLEEDING
PROCEDURE
1.
Refer to Figure 13. Install a small
BLEEDER BY-PASS LINE as
shown. A 1/4" size line or hose is
sufficient.
2.
Start engine and allow enough
time to pass for the system to
become filled and thoroughly
flushed with oil.
3.
It is necessary to develop between
50-200 PSI at the inlet to brake
valve. A method to throttle the oil
will be needed if the system does
not already have a secondary
hydraulic device downstream from
the brake valve.
PRESSURE SHOULD BE HELD
THROUGHOUT THE BLEEDING
PROCESS AND SHOULD NOT
EXCEED 250 PSI.
DOWNSTREAM SECONDARY
HYDRAULIC DEVICE SUCH
AS POWER STEERING
BRAKES
BLEEDER
BY-PASS LINE
(Remove after Bleeding)
4.
DO NOT STEP ON THE BRAKE
PEDAL DURING
BLEEDING PROCESS.
5.
Oil will now be forced directly into
the brake line by the pump and fill
the brake valve master cylinder
cavity. This may take a minute or
two.
6.
Continue to hold the bleed
pressure while bleeding each brake
starting with the line and brake
closest to the brake valve.
7.
Allow a sufficient amount of fluid
to pass at brake bleeder screw to
THIS insure all air is removed from each
bleeder point.
8.
Continue this method until all
brakes and lines are bled.
9.
When all brakes are bled and
fittings tight, release the 50-200
THIS
PSI pressure and SHUT OFF
ENGINE.
10. Remove the bleeder by-pass line
and plug the connections. Be sure
not to lose fluid or ingest air at the
brake line connection when
removing bleeder by-pass line.
11. With engine off, step on brake
pedal. It should be fairly high and
hard. If a spongy pedal is felt, the
system still contains air. If pedal
strokes downward too far, check
and readjust brakes and repeat
bleeding process.
12. When the pedal is satisfactory,
restart engine and actuate brake
pedal several times. Now check
for leaks.
PRESSURE

BLEEDING SCHEMATIC

FIGURE 13
(15)
Courtesy of Crane.Market