Remove hose guide (11) from the rear of the second boom section

23. Slowly pull the push beam out of the front of the third boom section. The extend cables will come out along with the push beam.

24. When the head of the push beam is out of the third boom section, stop and pull the extend cables the remaining of the way out over the cable sheaves of the push beam.

25. Slowly pull the push beam free of the machine and place on the ground or suitable support.

Note: The extend/retract hydraulic cylinder can be removed from the push beam if necessary.

26. Pull the retract cable from between the second and first boom section at the rear of the boom.

27. Slowly pull the third boom section free of the machine and place on the ground or suitable support.

3.4.2 Second Boom Section Removal

1. Pull the tilt hoses, and if equipped, the auxiliary

hoses, from the bottom rear of the boom sheaves.

2. Remove the wear pads from the front of the first boom section. Note the location of the wear pads, mounting bolts and number of shims from each location.

3. Remove the wear pads from the top rear and one side of the second boom section. Note the location of the wear pads, mounting bolts and number of shims from each location.

4. Loosen and remove the retract cable adjustment block (12) from the bottom front of the first boom section.

Note: It may be necessary to pull the boom section(s) out far enough to access the wear pads.

5. Slowly pull the second boom section out of the first boom section.

6. Lift the second boom section free of the machine and place on the ground or suitable supports.

3.4.3 Second and Third Boom Section Removal

It is best to remove the boom sections in the order in which they were assembled. If a section needs to be separated, this presents an excellent opportunity to check all sections for serviceability. The third and second sections can be removed as a assembly. The push beam/

extend-retract cylinder can be either removed or left in place during the third and second boom section removal.

1. Release tension from the hoses on the hose take-up bracket (3).

2. Label, disconnect and cap all hydraulic hoses attached at the take-up bracket (4). Cap all fittings and openings to keep dirt and debris from entering the hydraulic system.

3. If equipped, label, loosen and separate all electrical cables at the take-up bracket.

4. Remove the take-up brackets (5).

5. Loosen and remove the jam nuts on the retract cable (6) at the bottom of the first boom section.

6. Loosen and remove the retract cable adjustment block (12) from the bottom front of the first boom section.

7. Label, disconnect and cap both hydraulic hoses (7) attached to the extend/retract cylinder. Cap all fittings and openings to keep dirt and debris from entering the hydraulic system.

8. Loosen and remove the jam nuts on the two extend cables (8) at the strong back.

9. Remove the pin (9) holding the extend/retract cylinder at the strong back.

MX1380

10. Loosen and remove the bolts holding the strong back to the rear of the first boom section. Remove the strong back.

11. Remove the wear pads from the front of the first boom section. Note the location of the wear pads, mounting bolts and number of shims from each location.

12. Remove the wear pads from the top rear and one side of the second boom section. Note the location of the wear pads, mounting bolts and number of shims from each location.

Note: It may be necessary to pull the boom section(s) out far enough to access the wear pads.

13. Slowly pull the two boom sections out of the first boom section. The extend cables, retract cable and the tilt/aux hoses will come out along with the boom sections.

Pay close attention to the retract cable and tilt/aux hoses during the boom section removal as not to allow the cable or hoses to become jammed between the second and first boom sections.

14. Lift the two boom sections free of the machine and place on the ground or suitable supports.

3.4.4 Second Boom Section Installation

1. Grease the inside wear pad paths of the first boom

section and the outside wear paths of the second boom section.

2. Position the second boom section into the front of the first boom section. Leave room at the bottom front to install the retract cable adjustment block.

3. Install the retract cable adjustment block to the inside front of the first boom section.

4. Install the wear pads and shims in the front of the first boom section.

5. Install the wear pads and shims at the top rear and one side of the second boom section.

6. Feed the tilt hoses (and auxiliary hoses if equipped) through the bottom of the hose sheaves at the rear of the second boom section.

Note: Make sure the tilt/aux hoses do not cross each other between the first and second boom sections.

7. Install the hose take-up brackets and install the tilt/

aux hoses to the correct fittings on the take-up brackets.

3.4.5 Third Boom Section Installation

1. Grease the inside wear pad paths of the second

boom section and the outside wear paths of the third boom section.

2. With the retract cable fed through the front of the second boom section, position the third boom section into the front of the second boom section.

3. Feed the retract cable over the cable sheave at the rear of the second boom section and out the rear of the first boom section.

4. Install the wear pads and shims in the front of the second boom section.

5. Install the wear pads and shims at the top rear and one side of the third boom section.

6. Install the back of the push beam into the head of the third boom section. With the push beam installed 50% into the third boom section, feed the extend cables through the bottom and over the cable sheaves.

7. Install the push beam into position and pin into place at the rear of the second boom section. Pull the third and second boom section out of the first section together approximately 12 in.to allow slack in the tilt/

aux hoses.

8. Install the bulkhead brackets at the front of the third boom section.

9. Feed the tilt/aux hoses through the trays at the bottom corners of the third boom sections.

10. Uncap and reconnect the previously labeled tilt/aux hoses to the fittings on the bulkhead brackets.

11. Push the third and second boom section back against the first boom section.

12. Install the strong back and pin the extend/retract to the strong back.

13. Uncap and reconnect the previously labeled extend/

retract hoses to the fittings on the extend/retract cylinder.

14. Feed the extend cables through the strong back and install the jam nuts on each cable.

15. Install the guide and cable cover on the front of the push beam.

16. Install the tilt cylinder and hoses in the third boom section boom head.

17. Install the hose and cable cover at the rear of the second boom section.

18. Adjust the boom sections, cables and hoses to the proper dimensions.

3.5 BOOM CABLES - THREE SECTION

3.5.1 General Cable Information

The 534D-9 & 534D-10 Parts Manual covers part numbers, length and key specifications. Please review this manual to make certain that you are using the correct cable for your machine. DO NOT use cable other than that supplied by JLG for replacement. These cables are specifically designed for JLG Material Handlers.

• Cables are pre-stretched; lengths cited below are after pre-stretching.

• Threaded stud, Galvanized Plating.

• Safe Lock Closed Socket Terminal used on Extend Cable.

• Safe Lock or Spelter Socket used on Retract Cable.

• Boom Cable length tolerance: +0.5 in / -1.0 in (12,7 mm - 25 mm).

• Use two wrenches when torqueing adjusting jam nuts. Use the flats on the threaded cable ends to hold the cable straight, eliminating twist.

3.5.2 Cable Adjustments

The cables are adjusted by tightening and/or backing off the adjusting nuts at the threaded end of the cable.

Tightening the retract cable adjusting nuts pulls the third boom section in, to the rear. Tightening the extend cables adjusting nuts pulls the third boom section out, to the front. The opposite cable adjusting nut usually must be loosened whenever this procedure is performed.

The cables are properly adjusted whenever the following parameters are met.

534D-9, 534D-10:

The extend/retract cylinder rod eye pin (1) is centered in the side access hole of the push beam and/or the dimension (2) from the front of the third boom section to the front of the second boom section is 17.5 in

(444,5 mm).

MX0200

1 2

3.5.3 Retract Cable Removal

The removal of the retract cable is a difficult operation;

but it can be accomplished. You must be able to reach into the rear of the boom assembly to unfasten the retract cable socket from the cable anchor bracket weldment. If you cannot reach this bracket, the boom sections must be separated.

1. Remove any attachment from the quick switch assembly. Refer to Section 3.16.1, “Disconnecting from an Attachment.”

2. Park the machine on a hard, level surface, fully retract the boom, level the boom assembly, place the transmission control lever in (N) NEUTRAL, engage the park brake and shut the engine OFF.

3. Place a Do Not Operate Tag on both the ignition key switch and the steering wheel, stating that the machine should not be operated.

4. Open the engine cover. Allow the system fluids to cool.

5. Remove the battery negative (-) cable from the battery negative (-) terminal.

6. Remove the hose guards from the rear of the first boom section.

7. Label, disconnect and cap all extend/retract hydraulic hoses. Cap all fittings and openings to keep dirt and debris from entering the hydraulic system.

8. Remove the extend/retract cylinder mounting pins (3) from the strong back/cylinder bracket.

9. Remove the extend cable lock nuts, washers and springs (4) from the strong back/cylinder bracket.

10. Pull the cable free of the strong back/cylinder bracket. Fasten a rope to the cable end to aid in reinstallation.

11. Remove the strong back/cylinder bracket mounting bolts and remove the strong back bracket (5) from the machine. Label and tag each set of shims being removed from above and below the strong back.

12. Remove the push beam mounting pins (6) and from

In document 534D-9,534D-10, And 544D Service Manual (Page 37-41)