Gradall 544D (9136-4003) Service Manual User Manual download pdf (Page 391)

Refer to Figure 13. Install a small

BLEEDER BY-PASS LINE as

shown. A 1/4” size line or hose is

sufficient.

Start engine and allow enough

time to pass for the system to

become filled and thoroughly

flushed with oil.

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. THIS

PRESSURE SHOULD BE HELD

THROUGHOUT THE BLEEDING

PROCESS AND SHOULD NOT

EXCEED 250 PSI.

PRESSURE BLEEDING

PROCEDURE

1.

2.

3.

DO NOT STEP ON THE BRAKE

PEDAL DURING THIS

BLEEDING PROCESS.

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.

Continue to hold the bleed

pressure while bleeding each brake

starting with the line and brake

closest to the brake valve.

Allow a sufficient amount of fluid

to pass at brake bleeder screw to

insure all air is removed from each

bleeder point.

Continue this method until all

brakes and lines are bled.

When all brakes are bled and

fittings tight, release the 50-200

PSI pressure and SHUT OFF

ENGINE.

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.

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.

When the pedal is satisfactory,

restart engine and actuate brake

pedal several times. Now check

for leaks.

4.

5.

6.

7.

8.

9.

10.

11.

12.

(15)

FIGURE 13

BLEEDING SCHEMATIC

DOWNSTREAM SECONDARY

HYDRAULIC DEVICE SUCH

AS POWER STEERING

PRESSURE

BRAKES

BLEEDER

BY-PASS LINE

(Remove after Bleeding)

FLOW-THRU

RETURN

LINE

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