Usage:
D20D (9MG),
D250D (6NG),
D300D (5MG),
D25D (1HK),
D30D (3AJ, 1PK),
D350D (9RF),
D40D (2JJ),
D400D (8TF, 4EJ) Articulated Trucks
Reference: Special Instruction, Articulated Truck Hitch Salvage, SEHS9807.
A procedure has been developed for measuring oscillating hitch wear on current articulated trucks. There are two measurements, axial (fore and aft thrust face wear) and radial, to be made when measuring oscillating hitch wear. Using the following procedure will help determine the amount of wear and help make decisions as to repair options.
Making Oscillating Hitch Measurements
Machine Preparation
1. Park the machine on a flat and level surface.
2. Lower the front suspension and shut off the engine. Do NOT engage the parking brake.
3. Place suitable blocks in front of the front wheels and behind the rear wheels.
NOTE: Do not apply the parking brake after blocking the wheels. The hitch must not have any "wind-up" while the measurements are being made.
Making The Axial Oscillating Hitch Measurements
Locking Plate (1). Hitch Thrust Flange (2).
1. Remove the locking plate (1) on the hitch thrust flange (2). Tighten the flange to the tightest position that will allow installation of the locking plate.
NOTE: On early machines, adequate torque can be applied to the thrust flange using an FT-2414 Spanner and suitable piece of heavy pipe that is 0.9 m (3.0 ft) long. Approximately 445 N (100 lb) to 667 N (150 lb) of force applied at the end of the pipe is adequate to tighten the flange.
A new locking plate and thrust flange is effective with D25D 1HK471), D30D (3AJ337), D40D (2JJ101), D350D (9RF543) and D400D (8TF850) Articulated Trucks. The new locking plate has a 19.0 mm (.75 in) square hole. The square holes allows adjustment to be done with a 3/4in drive wrench instead of the FT-2414 Spanner. The procedure for adjustment does not change.
2. Use a feeler gauge to measure the gap (A) between the locking plate and the flange as shown in the illustration. This measurement is the axial measurement.
3. After taking the axial measurement, remove the locking plate (1) and loosen the flange (2) one notch to give the recommended 0.15 to 0.40 mm (.006 to .016 in) end float.
4. Install the locking plate (1).
Measuring Radial Oscillating Hitch Wear
1. Install a dial indicator (3) with a magnetic base as shown in the illustration. The magnetic base should be on the tractor hitch (B) and the indicator should be on the trailer frame (C). Place the magnetic base and indicator as close as possible to the centerline of the machine.
2. For all machines except the D350D and D400D Articulated Trucks, a hydraulic jack can be placed under either the tractor hitch or the trailer frame. Raise the machine until the dial indicator stops moving.
For the D350D and D400D Articulated Trucks, place the jack under the front bumper. Raise the front bumper until the dial indicator stops moving.
Axial And Radial Wear Limits
The axial and radial wear limits are shown in the chart. If the wear measurements taken are at or above the limits, the hitch may need to be either rebuilt or replaced. See the REFERENCE Article, which has complete information for determining if a hitch can be rebuilt. The REFERENCE Article also has the rebuild procedure.
