Usage:
D350E (9LR),
D400E (2YR) Articulated Trucks
Reference: Service Magazine, SEPD0385; October 6, 1997; Page 44; "Proper Welding Procedure On Machines And Engines With Electronic Controls".
Reference: Service Manual Module, SENR8682; Systems Operation Testing & Adjusting, D350E & D400E Articulated Trucks Brake System; This module is part of SENR8675, D350E & D400E Articulated Trucks Service Manual.
Description of Change: New brake lines and a lines routing change have increased the service life of the braking system of machines when operating in muddy, rocky, and poor underfoot conditions.
Adaptable To: The new 155-6244 Hose Assembly (one on each side) has replaced the former 126-1057 and 126-1058 Tube Assemblies. This new hose assembly is not serviced as an assembly, but the hoses and fittings required are listed in Illustration 7 and the associated chart. Two new 155-6242 Clamps with two each of new 5P-7464 Clips and 5P-7465 Clips and 6V-1249 Grommets replace two former 7U-3295 Spacers. Two new 156-1507 Guards with four new 6J-0499 Bosses have also been added. These changes are effective with D350E (9LR557) and D400E (2YR899) Articulated Trucks and are adaptable to earlier machines with the following procedures
NOTE: Refer to Service Magazine, SEPD0385; October 6, 1997; Page 44; "Proper Welding Procedure On Machines And Engines With Electronic Controls".
Weld Information
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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.
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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.
See 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.
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. The weld deposited by these electrodes will have the following minimum mechanical properties:
- 500 MPa (72 KSI) Tensile Strength
- 420 MPa (60 KSI) Yield Strength
- 22% elongation in 50 mm (2 in)
- 27 J (20 ft lb) Notch Toughness at -29° C (-20° F)
- 420 MPa (60 KSI) Yield Strength
These are low hydrogen electrodes and must be stored in an electrode oven at 121° C (250° F) when not in use. If the electrodes get damp, scrap or recondition them to the manufacturer's specifications.
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.
As an alternate process the FCAW process may be used with E71T-1 (ANSI/A5.20) welding electrode and the manufacturer's specified shielding gas(es). The weld deposited by three electrodes will have the following minimum mechanical properties:
- 500 MPa (72 KSI) Tensile Strength
- 420 MPa (60 KSI) Yield Strength
- 22% elongation in 50 mm (2 in)
- 27 J (20 ft lb) Notch Toughness at -18° C (0° F)
- 420 MPa (60 KSI) Yield Strength
NOTE: This type of electrode has limitations if it is used to carry larger weld pass volumes in the flat welding position. Due to the fast freezing characteristics of this electrodes slag system, there is a chance of trapping evolving gases in the weld melt. Precaution should be taken by controlling weld pass size.
Welding parameters will vary due to weld position and manufacturer of the welding electrode. For 1.30 mm (.052 in) diameter electrode typical welding parameters should be:
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 8.0 mm (.031 in) fillet volume.
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.
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The suspension system may drop the machine suddenly, leaving no clearance between the axle housing, main frame, tires, and mud guards. Working in these areas can result in personal injury or death by crushing. Stay clear until the engine is stopped and the suspension is lowered to the service position.
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Trapped pressure in a hydraulic system can cause sudden machine or implement movement. Also, release of high pressure when disconnecting lines and fittings can cause hoses to "whip" and oil to spray. Any of these situations can cause injury to persons on or near the machine. Do the procedure that follows to relieve pressure before testing and adjusting the braking system.
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1. Move the machine to a smooth horizontal location, away from other machines and personnel. Stop the engine.
2. Allow only one operator on the machine. Keep all other personnel either away from the machine or in view of the operator.
3. Engage the parking brake and lower the body to the frame.
4. Carefully loosen the filler cap on the hydraulic tank to release the pressure in the tank.
5. Make sure all hydraulic pressure is released before any fitting, hose or component is loosened, tightened, removed or adjusted.
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Fluid Spillage Containment: Care must be taken to ensure fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to "Tools and Shop Product Guide, NENG2500", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose fluids according to local regulations and mandates.
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Illustration 1.
New front brake line routings. Arrows depict new 155-6244 Hose Assemblies.
Illustration 2.
Dimensions required to produce plate for 155-6242 Clamp 0.8 mm (.31 in) thick.
Illustration 3.
Weldment to produce 155-6242 Clamp. Use 7U-3295 Spacer and plate produced from dimensions in Illustration 2.
Illustration 4.
123-7911 Frame Gp - Suspension. Arrow depicts two 7U-3295 Spacers used in Illustration 3.
Illustration 5.
Dimensions to weld two 6J-0499 Bosses on each side.
Illustration 6.
View of 156-1507 Guard bolted onto bosses from Illustration 5.
Illustration 7.
Dimensions and parts to make 155-6244 Hose Assembly.
