Doubles And Triples Practice Questions
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- The air tank petcock
- The emergency air line
- The dolly parking brake control
- The parking brake release knob
From The CDL Manual
Release dolly brakes by opening the air tank petcock. (Or, if the dolly has spring brakes, use the dolly parking brake control.)
- Get your dispatcher to help
- Move it by hand
- Ask the shipper to do it
- Call a friend
From The CDL Manual
If the distance is not too great, wheel dolly into position by hand so it is in line with the kingpin.
- Removed
- Lowered
- Half-way up
- Raised
From The CDL Manual
Hook dolly to front trailer.
- Lock pintle hook.
- Secure converter gear support in raised position.
- Require high RPM's to get under it
- Be 4.5 feet off the ground
- Raise slightly when dolly moves under it
- Completely clear the dolly
From The CDL Manual
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.)
- Closed
- Open
- Disconnected
- Half-open
From The CDL Manual
Open shut-off valves at rear of first trailer (and on dolly if so equipped).
- The locking jaws have closed on the kingpin
- There is space between the upper and lower fifth wheel
- The locking jaws are open
- Landing gear is completely lowered
From The CDL Manual
Raise landing gear slightly off ground to prevent damage if trailer moves.
Make visual check of coupling. (No space between upper and lower fifth wheel. Locking jaws closed on kingpin.)
- Opening the emergency line shut-off
- Looking at your air gauges
- Trying to pull the trailer
- Pumping the brakes repeatedly
From The CDL Manual
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 is not there, something is wrong and the brakes will not work.
- Free-rolling
- Raised off the ground
- Half-flat to avoid rolling
- Locked and/or chocked
From The CDL Manual
Connect converter dolly to rear trailer:
Make sure trailer brakes are locked and/or wheels chocked.
- In a truck stop parking lot
- On an uphill incline
- At a 45 degree angle to the trailer
- In a straight line on firm level ground
From The CDL Manual
Uncouple rear trailer:
Park in a straight line on firm level ground.
- Lower trailer landing gear
- Apply rig parking brakes
- Disconnect dolly air and electric lines
- Pull tractor, trailer and dolly out
From The CDL Manual
Uncouple rear trailer:
- Park in a straight line on firm level ground.
- Apply parking brakes so rig will not move.
- Chock wheels of second trailer if it does not have spring brakes.
- Lower landing gear of second semitrailer enough to remove some weight from dolly.
- Close air shut-offs at rear of first semitrailer (and on dolly if so equipped).
- Disconnect all dolly air and electric lines and secure them.
- Release dolly brakes.
- Release converter dolly fifth wheel latch.
- Slowly pull tractor, first semi-trailer and dolly forward to pull dolly out from under rear semi-trailer.
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