3. What three methods can you use to secure a second trailer before coupling?
- COUPLING TWIN TRAILERS
- SECURE SECOND (REAR) TRAILER
- • If the second trailer doesn't have spring brakes, drive the tractor close to the trailer, connect the
- emergency line, charge the trailer air tank, and disconnect the emergency line. This will set the
- trailer emergency brakes (if the slack adjusters are correctly adjusted). Chock the wheels if you
- have any doubt about the brakes.
- COUPLE TRACTOR AND FIRST SEMI-TRAILER AS DESCRIBED EARLIER
- ***Caution:For the safest handling on the road, the more heavily loaded semi-trailer should
- be in first position behind the tractor. The lighter trailer should be in the rear.***
- A converter gear or dolly is a coupling device of one or two axles and a fifth wheel by which a semitrailer
- can be coupled to the rear of a tractor-trailer combination forming a double bottom rig.
- 1.) POSITION CONVERTER DOLLY IN FRONT OF SECOND (REAR) TRAILER
- • Release dolly brakes by opening the air tank petcock. (Or, if the dolly has spring brakes, use
- the dolly parking brake control.)
• If the distance is not too great, wheel dolly into position by hand so it is in line with the kingpin.
• Or, use the tractor and first semi-trailer to pick up the converter dolly:
- Position combination as close as possible to converter dolly.
- Move dolly to rear of first semi-trailer and couple it to the trailer.
- Lock pintle hook.
- Secure dolly support in raised position.
- Pull dolly into position as close as possible to nose of the second semi-trailer.
- Lower dolly support.
- Unhook dolly from first trailer.
- Wheel dolly into position in front of second trailer in line with the kingpin.
2.) CONNECT CONVERTER DOLLY TO FRONT TRAILER
• Back first semi-trailer into position in front of dolly tongue.
• Hook dolly to front trailer.
- Lock pintle hook.
- Secure converter gear support in raised position.
3.) CONNECT CONVERTER DOLLY TO REAR TRAILER
• Make sure trailer brakes are locked and/or wheels chocked.
- • Make sure trailer height is correct. (It must be slightly lower than the center of the fifth wheel, so
- trailer is raised slightly when dolly is pushed under.)
• Back converter dolly under rear trailer.
• Raise landing gear slightly off ground to prevent damage if trailer moves.
• Test coupling by pulling against pin of number two semi-trailer.
- • Make visual check of coupling. (No space between upper and lower fifth wheel. Locking jaws
- closed on kingpin.)
• Connect safety chains, air hoses, and light cords.
- • Close converter dolly air tank petcock and shut-off valves at rear of second trailer (service and
- emergency shut-offs).
• Open shut-off valves at rear of first trailer (and on dolly if so equipped).
• Raise landing gear completely.
- • Charge trailers (push "air supply" knob in) and check for air at rear of second trailer by opening
- the emergency line shut-off. If air pressure isn't there, something is wrong and the brakes won't
- work.
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