Usage:
24H (7KK) Motor Graders
Description of Change: The rear louvered doors are now mounted only to the engine enclosure, with new straps to support them. The former design mounted the doors to the engine enclosure and to the radiator support.
Adaptable To: The change to the 8X-8991 Engine Enclosure is effective with 24H (7KK75) Motor Graders and is adaptable to earlier machines with the following procedure.
Procedure To Adapt Earlier Machines:
NOTE: Steps 1 through 3 are not necessary if new tube assemblies are ordered as referenced in Table 1.
1. Fabricate six blocks using Illustration 1.
Illustration 1.
Fabricate six blocks using 16 mm thick of ASTM A36.
2. Weld the blocks from Step 1 to the two existing tube assemblies. Refer to Illustration 2 and the Weld Procedure listed below.
Illustration 2.
Typical location of blocks.
3. Cut three notches in the two existing door assemblies. Refer to Illustration 3. Note: If the doors are damaged, they should be replaced.
Illustration 3.
Typical Door Assembly with new notches.
4. Remove the former bolts, washers and hinge assemblies.
5. Assemble the six new 167-0785 Straps to the new or modified tube assemblies, using the (24) new 7X-7729 Washers and the (24) new 8T-4137 Bolts. Tighten the bolts to a torque of 45 to 65 N·m (33.3 to 48.1 lb ft).
Illustration 4.
Typical Door Assembly.
Illustration 5.
Top View of Engine Enclosure.
Illustration 6.
View A-A from Illustration 5.
Refer to Service Magazine, October 6, 1997, Page 44, "Proper Welding Procedure On Machines And Engines With Electronic Controls".
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Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can kill.
Read and understand the manufacturer's instructions and your employer's safety practices. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing zone and general area. Wear correct eye, ear, and body protection. Do not touch live electrical parts.
Refer to the American National Standard Z49.1 "Safety in Welding and Cutting" published by the American Welding Society, 2501 N.W. 7th Street, Miami, Florida 33125: OSHA Safety and Health Standards, 29 CRF 1910, available from U.S. Dept. of Labor, Washington, D.C. 20408.
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Weld Specifications And Parameters
NOTE: Welding operator personal protection should be provided to assure that total weld fume in the operators breathing zone does not exceed OSHA limits.
All repair welding operators must be qualified for groove and fillet welding, as outlined the current ANSI/AWS D14.3. The qualification will be for the SMAW (Shielded Metal Arc Welding) process in the vertical welding positions. The welding operator must also have used this welding process during the last six months or be re-certified for this process before welding. Documentation must be maintained of the weld operators qualifications. The alternate process for this repair could be FCAW (Flux Cored Arc Welding).
The area to be welded and the surrounding area must be at a minimum temperature of 16° C (60° F) before and during welding.
NOTE: Since weld distortion is a possibility, minimizing the heat is important.
The SMAW process shall be used with E7018 (ANSI/ AWS A5.5) welding electrode in open environments. The GMAW or the FCAW (Flux Cored Arc Welding) should be used in enclosed environments. The weld deposited by these electrodes will have the following minimum mechanical properties:
- 500 MPa (72 KSI) Tensile Strength
- 500 MPa (60 KSI) Yield Strength
- 420 22% elongation in 50 mm (2 in)
- 27 J (20 ft lb) Notch Toughness at -29° C (-20° F)
- 500 MPa (60 KSI) Yield Strength
These are low hydrogen electrodes and must be stored in an electrode oven at 120° C (250° F) when not in use. If the electrodes get damp, scrap or recondition them to the manufacturer's specifications.
Where possible, welds should be made in the flat or horizontal position.
The following chart relates to the electrodes diameter and approximate current settings for welding:
Use the direct current electrode positive (DC reverse polarity) polarity setting and remove the slag after every pass. The weld pass size shall not exceed two times the electrode diameter.
Welding parameters will vary due to weld position and manufacturer of the welding electrode.
Clean the metal of oil, grease, paint, and dirt in the area to be welded. Attach the welding ground cable directly to the area to be welded. Protect all machined surfaces from sparks or splatter produced by the welding, chipping, and/or grinding operations.
The welds shall be free from cracks, porosity, undercut, and incomplete fusion. All weld quality shall conform to ANSI/AWS D14.3.