JLG 740AJ, Service And Maintenance Manual

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SECTION 5 - BASIC HYDRAULIC INFOR M ATION AND SCHE M ATICS
5-94 3121160
Manual Servo Control Basic Assembly
DISASSEMBLY
1. Remove wiper seal with screw driver. Remove set screw
retaining input shaft and remove input shaft from con-
trol housing.
2. Remove set screw from plug retaining valve spool and
remove plug.
3. Remove o-ring from pin retaining feedback link and
valve spool. Remove pin, feedback link, valve spool, and
bell crank from control housing.
4. Compress spring and remove o-ring, spring retainer,
spring, and second spring retainer from valve spool.
5. Remove o-rings from plug and input shaft. Clean all
parts and lubricate in prep for reassembly.
ASSEMBLY
1. Install spring retainer, spring, and second spring retainer
onto spool. Compress spring with retainer and retain
with o-ring onto valve spool.
2. Install valve spool into control housing making sure that
metering notches on valve spool can be seen in the
metering ports. Notches shown in Figure 5-141.
3. Position bell crank in housing. Slide feedback link into
position between clevis on valve spool, aligning holes,
and install dowel pin retaining with o-ring.
4. Install new o-ring onto input shaft. Hold bell crank in
position with feedback link slot and align splined hole of
bell crank with input shaft cavity. Install input shaft into
control housing and bell crank.
5. JLG Threadlocker P/N 0100011 or equivalent to set
screw and install retaining input shaft. Adjust set screw
until it bottoms out on input shaft and back out one-
quarter turn.
6. Install wiper seal on input shaft as shown in Figure 5-
141. Install new o-ring onto plug. retaining valve spool,
and install plug. Adjust plug until there is no play in the
valve spool with input shaft held stationary. Lock in
place with set screw. Torque set screw 17 to 25 in. lbs.
(2 to 3 Nm).
1. Control Housing
2. Plug
3. 0-ring
4. Retaining Ring
5. Spring Retainer
6. Spool Centering Spring
7. Valve Spool
8. Set Screw
9. Feedback Link
10. Dowel Pin
11. Retaining Ring
12. Bell Crank
13. Set Screw 14. Input Shaft
15. 0-ri ng
16. Wiper Seal
17. Head Pin
Figure 5-141. Manual Servo Control Basic Assembly
Metering Notches
Wide Band Neutral Spool
Identification Mark
Metering Notches
Wiper Seal
2
3
4
5
6
5
7
1
8
12
10
9
11
17
13
14
15
16
Head pin removal not required
From bell crank.