2001/11/12 Caterpillar

Off-Highway Truck/Tractor:

769D (S/N: 5SS1-UP)

773D (S/N: 7CS1-UP)

777D (S/N: AGC1-UP)

771D (S/N: 6YS1-UP)

775D (S/N: 8AS1-UP)

Service Magazine SEPD0604, 12 November 2001, "The Rear Glass for the Cab has Changed". Disregard this article. See the replacement article that follows.

Description of Change: The rear glass for the cab of certain Off-Highway Truck/Tractors has changed .

Adaptable To: The former 106-8288 Glass has been replaced with a new 183-8576 Glass. The 106-8288 Glass is still available for other models of trucks.

The change is effective with the following models: 769D (S/N: 5SS306), 771D (S/N: 6YS190), 773D (S/N: 7CS352), 775D (S/N: 8AS353) and 777D (S/N: AGC196).

The new glass is smaller than the former glass. The new glass needs a new plate and a seal in order to install the glass in the older models. Use the following information to install the new parts in the older cab.

All welders must be qualified in the Flux Cored Arc Welding (FCAW) process for a groove weld or a fillet weld.

Refer to the following American National Standards Institute - American Welding Society ANSI/AWS standard: D1.1. Prior to welding, the process must have been used by the welders during the last six months. Welding qualifications must be documented and welding qualifications must be current.

The proper electrode for stick welding for Shielded Metal Arc Welding (SMAW) is E7018. Refer to ANSI/AWS standard A5.1. The finished weld will have the following minimum mechanical properties:

• 480 MPa (69600 psi) Tensile Strength

• 400 MPa (58000 psi) Yield Strength

• 22% elongation

• 27 N·m (20 lb ft) at −29 °C (−20 °F) Impact Toughness

The following table is the electrode's current settings in relation to the electrode's diameters:

The E7018 electrodes are low hydrogen electrodes. The electrodes must be stored in an oven at a temperature of 120 °C (250 °F). If the electrodes get damp, scrap the electrodes or recondition the electrodes to the manufacturer's specifications.

Table 1

Parameters for Welding
Diameter	Amperes
3.2 mm (0.13 inch)	70-140
4.0 mm (0.16 inch)	110-180
4.8 mm (0.19 inch)	190-270

Set the polarity to direct electrode positive (reverse polarity). Use the direct current. Remove the slag after every pass. The width of the weld should not exceed two times the electrode diameter. Remove the slag after every pass.

Use the FCAW process with E71T-1 (ANSI/A5.20) welding electrode and the manufacturer's specified shielding gases for inside welding.

If the base metal is below 0 °C (32.0 °F), the base metal must be preheated to a minimum of 21 °C (70.0 °F). This temperature must be maintained during cutting and welding the part.

Clean the area that will be welded. Remove any oil, grease, paint and dirt. Attach the welding ground cable directly to the cab assembly. Protect all surfaces from sparks or spatter.

The welds should be free of the following defects: cracks, porosity, undercut and incomplete fusion.

The FCAW process may be used as an alternate welding process. Use E71T-1 ANSI/AWS A5.20 welding electrodes and the shielding gases that are recommended by the manufacturer. The weld that is deposited by these electrodes will have the following mechanical properties.

• 480 MPa (69600 psi) Tensile Strength

• 400 MPa (58000 psi) Yield Strength

• 22% elongation

• 27 N·m (20 lb ft) at −18 °C (0 °F) Impact Toughness

The welding parameters will vary because of the position of the weld and the manufacturer of the welding electrode. Refer to the following chart for the welding parameters for the electrode that is 1.30 mm (0.052 inch) in diameter.

Table 2

Wire Feed Speed Inch Per Minute	Voltage	Approximate Amperage
5080 mm (200 inch)	24	210
6985 mm (275 inch)	28	250
8255 mm (325 inch)	29	300

Table 3

Needed Parts
Item	Qty	Part Number	Description
1	1	189-2496	Plate
2	340 cm (134.0 inch)	5P-5768	Seal
3	1	183-8576	Glass

1. Remove the existing glass and seal from the cab.

   Note: Protect the area that may be damaged from the grinding process or the weld splatter.

2. Remove the paint from the area that will be welded.

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Illustration 1	g00835137
(1) 189-2496 Plate (W1) 3 mm (0.1 inch) fillet weld (A) Existing angle iron

3. Center the plate (1) on the existing angle iron (A) that surrounds the opening for the glass. Ensure that there is an equal amount of angle iron on opposite sides of the opening.

4. Use nine 3 mm (0.1 inch) fillet welds that are 50 mm (2.0 inch) in length to tack weld the plate (1) into position.

5. Completely weld the plate (1) with a 3 mm (0.1 inch) fillet weld.

6. Clean the weld and inspect the weld.

7. Paint the plate and the welded area in order to inhibit rust.

8. Install the seal (2) in the opening.

9. Install the glass (3) .