JLG G6-42A - Service Manual

Other manuals for JLG G6-42A

Supplemental Repair Manual180 pages

Questions and Answers

A
antonio28Jul 29, 2025
What to do if JLG Boom Lifts' seals leak oil?
- H
  Hannah SimpsonJul 29, 2025
  If the seals are leaking oil, replace the seal and the mating surface if damaged. Use the correct lubricant, fill to the correct level, and replace it at the recommended intervals. This issue may arise from prolonged operation with excessive oil temperature, improper oil seal installation, a cut or nicked seal edge, or dirty lubricant.
D
davidrussoAug 6, 2025
What to do if the axle beam body of JLG Boom Lifts is bent?
- H
  Heather BakerAug 6, 2025
  If the axle beam body is bent, replace it. This damage may be due to vehicle overloading, accidents, or impact from a load.
J
Jessica PorterAug 12, 2025
How to fix excessive wear on the entry flange groove of JLG Boom Lifts?
- R
  Rachel ColeAug 12, 2025
  To address excessive wear on the entry flange groove, replace the flange. Inspect the pinion groove for excessive wear and replace the ring gear and pinion if necessary. This issue may arise from heavy usage, a loose pinion nut, or pinion axial play.
D
Daryl CurryAug 20, 2025
How to repair worn or pitted bearings in JLG Boom Lifts?
- K
  Karen StewartAug 20, 2025
  Replace the bearings. Use the correct lubricant, fill to the proper level, and replace it at the recommended intervals. This issue may be due to insufficient lubrication, dirty lubricant, extremely intense use, normal wear, or a loose pinion nut.

Summary

General Guidelines for Rear Axle Weldment Repair

Weld Repair Guidelines and Safety

Tools and Equipment for Weldment Replacement

Personnel Qualifications for Repair

Parts List for Weldment Replacement

Rear Axle Block Weldment Replacement Procedure

Rear Axle Weldment Welding Locations

Details specific locations and dimensions for welding the rear axle weldment to the frame.

This document outlines the procedure for replacing the rear axle block weldment on a JLG machine, specifically for situations where both weld cracks and plate deflection are present. It emphasizes adherence to safety protocols and proper repair techniques to ensure the integrity and functionality of the equipment.

Function Description

The primary function of this procedure is to guide qualified personnel through the complete replacement of a damaged rear axle block weldment. This component is critical for the structural integrity and operational stability of the machine, supporting the rear axle and its associated mounting points. The replacement process involves several key stages: initial assessment, removal of the damaged weldment, preparation of the repair area, installation and welding of the new weldment, and final inspection and reassembly. The instructions are designed to ensure that the replacement is performed correctly, restoring the machine to a safe and operational condition. The procedure specifically addresses scenarios where the existing weldment exhibits both weld cracks and plate deflection, indicating a more severe structural issue that necessitates full replacement rather than just weld repair.

Usage Features

The instructions are structured to facilitate a systematic and safe replacement process. Key usage features include:

General Guidelines: These guidelines emphasize the importance of proper assessment to determine if this specific repair procedure is applicable. It clarifies that this procedure is exclusively for rear axle weldment replacement when both weld cracks and plate deflection are identified. If only weld cracks are present without plate deflection, a different repair procedure (31212011) should be followed.
Weld Repair Guidelines: Strict adherence to ANSI/AWS D1.1 Standard for all welding is mandated. Critical safety steps such as disconnecting the battery prior to welding and proper grounding techniques are highlighted to prevent component damage and ensure welder safety. Grounding is restricted to the component being welded, with explicit warnings against grounding to adjacent components or allowing conductive elements (pins, wear pads, bearings, etc.) to be between the grounding point and the weld area.
Tools & Equipment Required: A comprehensive list of necessary tools and equipment is provided, including stands and lifting equipment, hand-held power grinders, air carbon-arc equipment, electric welding equipment, specific AWS 70 grade low hydrogen rod or wire, standard welder tools, standard mechanic tools, and paint. This ensures that technicians are adequately prepared before commencing the repair.
Personnel Required: The procedure specifies that the work must be performed by a Qualified JLG Equipment Mechanic and a Certified Welder, underscoring the specialized nature of the repair and the need for expert involvement.
Parts List: A clear parts list identifies the required replacement component, in this case, the Rear Axle Weldment Block (P/N 91476013).
Step-by-Step Replacement Procedure: The core of the instructions provides a detailed, sequential guide for the replacement. This includes initial machine preparation (removing attachments, parking on a level surface, engaging parking brake, shutting off engine), safety measures (Do Not Operate Tag, disconnecting battery), and component removal.
Removal of Damaged Weldment: Specific instructions are given for using air carbon-arc equipment or a portable power grinder to remove the damaged rear axle mount weldments from the frame. A "NOTICE" emphasizes the importance of not damaging the parent metal during this process.
Inspection and Preparation: After removal, the affected areas must be inspected for cracks, and any discrepancies require further evaluation by a certified welder. The repair area is then prepared for the new weldment.
Installation and Welding: The new axle weldment (P/N 91476013) is located and tack welded into position, followed by full welding using the recommended weld material.
Post-Weld Inspection: Welds must be inspected using magnetic particle or dye-penetrant methods to ensure the absence of cracks or deformities. Any identified defects necessitate grinding to remove the affected area and repeating the weld and inspection procedures.
Finishing and Reassembly: After welding, the weld bars are removed from the new weldment (with a "NOTICE" to avoid damaging the new weldment). The affected areas are then cleaned, primed, and painted. Previously removed components are reinstalled, protective coverings are removed, and the battery is reconnected.
Functional Verification: The procedure includes steps to cycle the drive, steer, and frame level functions multiple times to verify proper operation. Clearance between the frame, rear axle, hydraulic hoses, and electrical wires must be checked.
Final Steps: The previously removed attachment is reinstalled, the Do Not Operate Tag is removed, and the machine is returned to service.
Welding Locations Diagram: Diagrams illustrating the rear axle weldment welding locations are provided, specifying weld sizes (e.g., 3/8, 5/16) and indicating that welding should occur all around except against the rear plate. A specific dimension (A. 1.0 in (25.4 mm)) is also noted.

Maintenance Features

While primarily a repair procedure, several aspects contribute to the long-term maintenance and reliability of the machine:

Quality Assurance through Inspection: The mandatory inspection of welds using magnetic particle or dye-penetrant methods ensures that the new weldment is installed without defects that could lead to premature failure. This proactive inspection is a critical maintenance feature, preventing future issues arising from faulty repairs.
Proper Surface Preparation and Finishing: Cleaning, priming, and painting the affected areas after welding are essential maintenance steps. This protects the newly welded and repaired surfaces from corrosion and environmental damage, extending the lifespan of the repair and the machine.
Adherence to Standards: Requiring all welding to conform to the ANSI/AWS D1.1 Standard ensures that the repair meets recognized industry quality and safety benchmarks, contributing to the overall reliability and maintainability of the equipment.
Documentation and Reference: The instruction set itself serves as a maintenance document, providing a clear, repeatable process for a specific repair. This ensures consistency in repairs across different technicians and contributes to a standardized maintenance approach.
Functional Checks Post-Repair: Cycling machine functions (drive, steer, frame level) and verifying clearances after reassembly are crucial maintenance checks. These steps confirm that the repair has not introduced new operational issues and that all systems are functioning correctly, preventing potential breakdowns or safety hazards.
Qualified Personnel Requirement: Insisting on certified welders and qualified mechanics for this repair ensures that the work is performed by individuals with the necessary skills and knowledge, leading to a higher quality and more durable repair, which is a key aspect of effective maintenance.
Damage Prevention: Instructions like protecting hoses, wires, and hydraulic cylinder rods during welding and removing weld bars carefully are preventative maintenance measures that safeguard other critical components from damage during the repair process.
Service Manual Reference: The repeated instruction to "Refer to the machine Service Manual for proper disassembly procedures" and "for proper assembly procedures" integrates this specific repair into the broader maintenance framework of the machine, ensuring that all related tasks are performed according to manufacturer specifications.