IV. Unique Vehicle Features

• A. Chains:

  The need for tire chains is a rare occurrence. Installation is covered during Mountain Training.

  • 1. Make sure chains are tight;

    2. Do not exceed 30 mph;

    3. Never run chains on dry pavement.

• B. Electric Retarders:

  All buses are equipped with retarders. They are non-friction brakes that operate with electric current and magnetic drag rather than conventional brake pads.

  • 1. They should always be used as the primary braking device; especially when descending mountain grades or on slippery surfaces.

    2. Retarders use a lot of current; never run the bus against it, as it will overheat. Never leave the retarder on while bus is idling.

    3. There are four levels of braking on the retarder with level four providing the most braking power. Use the higher levels sparingly; if you find that you still cannot adequately slow down, your transmission gearing is too high. Downshift into a low gear along with the retarder

    4. The retarders get extremely hot during use. Always allow the retarder to cool down after use by driving approx. one mile with it off before shutting down. It is absolutely essential that the retarder be allowed to cool down for at least 10 minutes after heavy 3rd or 4th position use, otherwise warping will occur.

    5. The same procedures and cautions apply for in-transmission retarders. (new buses)

  C. Thomas Transit Buses:

  • 1. When you start the bus the air box heater draws down the batteries and the voltmeter will probably read about 12. Engage the "fast idle" switch and rev the engine briefly to 1200rpm to activate the alternator. This will compensate for the battery drainage and the voltmeter should read normal (14). To minimize electrical drain, do not check heaters or radios until the end of your pre-trip.

    2. Do not drain the air tanks under the bus, this will be done during PM checks.

    3. Do not drain the air from the rear door, use the "Willie lock" to block rear door.

    4. To lock up front door, leave door in closed position, open air valve and leave open, operate the door manually and then use key lock on outside of door.

    5. Never open rear door while bus is in motion, this will activate spring brakes. Always apply parking brake before opening the rear door and shut the rear door before releasing brake. The engine will not start with the rear door open.

    6. Proper tire inflation is 90lbs. all around, check with gauge on hose or in bus box.

• D. 24 Passenger Vans:

  These operate just like any other conventional gasoline automobile.

  • 1. start-up procedures:
    • a. Turn ignition on;

      b. Be sure the master electric switch is on;

      c. Be sure the retarder "on/off" switch is on.

    2. shut-down procedures:

    • a. Just turn key off. If bus "runs-on," depress accelerator until it stops;

      b. switch off all electrics including radios;

    3. If you need to add brake fluid, do not use DOT-3 fluid! You must use DOT-5 silicone brake fluid.

    4. If the 24-passenger van is equipped with an "air-ride" system. The air bags located on either side of the vehicle above the rear wheels. Make sure these are inflated to between 50 and 70lbs and are equal on both sides.

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Last updated on 7/10/96.