ASTM D4998 Standard Test Method for Evaluating Wear Characteristics of Tractor Hydraulic Fluids
6. Apparatus
6.1 FZG Gear Oil Test Machine - The test machine is described in Annex A1 and illustrated in Fig. A2.1 and Fig. A3.1.

6.2 Precision Test Gears - The test gears are standard FZG tooth profile A gears as described in Annex A1 and Table A1.1.

6.3 Gear Case Heater - A 750 W gear case heater capable of bringing the oil to test temperature in (20 to 25) min.

6.4 Temperature Controller - A proportional band-type 1000 W temperature controller for maintaining the oil temperature within 1 °C of the desired test temperature. The thermocouple is securely attached to the inside right wall of the gear case, 28 mm from the rear wall and 60 mm from the bottom, projecting 15 mm into the gear case.

6.5 Analytical Balance - An analytical balance with 2 kg capacity and accurate within 1 mg for weighing test gears.

6.6 Magnifying Lens, of 3 to 6 power.

6.7 Compressed Air - 551 kPa minimum.

6.8 Steam Hot Plate, or bearing heater, with surface temperatures below 75 °C.

7. Reagents and Materials
7.1 Mineral Spirits Solvent - Commercial grade, conforming to the requirements of Specification D235. (Warning - Flammable. Vapor harmful. Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid prolonged breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.)

7.2 Acetone - Commercial grade, conforming to the requirements of Specification D329. (Warning - Flammable. Vapor harmful. Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid prolonged breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.)

7.3 Pentane - Commercial grade n-pentane, conforming to the requirements of Table A5.1. (Warning - Flammable. Vapor harmful. Keep away from heat, sparks, and open flame. Keep container closed. Use with adequate ventilation. Avoid prolonged breathing of vapor or spray mist. Avoid prolonged or repeated skin contact.)

8. Preparation of Apparatus
8.1 Assemble the FZG machine according to the "Operating Instructions for the FZG Gear Oil Test Rig" except that the drive motor and gearing must be modified to provide an input shaft speed of (100 +/- 3) r/min. Use the S23 torsional shaft in assembling. Care must be taken to ensure the accuracy of shaft alignment as described in 6.3.