Doubles And Triples Practice Questions
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- The parking brake release knob
- The dolly parking brake control
- The air tank petcock
- The emergency air line
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.)
- Move it by hand
- Get your dispatcher to help
- Call a friend
- Ask the shipper to do it
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.
- Lowered
- Removed
- Raised
- Half-way up
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
- Raise slightly when dolly moves under it
- Completely clear the dolly
- Be 4.5 feet off the ground
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.)
- Disconnected
- Open
- Half-open
- Closed
From The CDL Manual
Open shut-off valves at rear of first trailer (and on dolly if so equipped).
- Landing gear is completely lowered
- The locking jaws are open
- The locking jaws have closed on the kingpin
- There is space between the upper and lower fifth wheel
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.)
- Trying to pull the trailer
- Pumping the brakes repeatedly
- Looking at your air gauges
- Opening the emergency line shut-off
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
- Locked and/or chocked
- Half-flat to avoid rolling
From The CDL Manual
Connect converter dolly to rear trailer:
Make sure trailer brakes are locked and/or wheels chocked.
- On an uphill incline
- At a 45 degree angle to the trailer
- In a truck stop parking lot
- In a straight line on firm level ground
From The CDL Manual
Uncouple rear trailer:
Park in a straight line on firm level ground.
- Pull tractor, trailer and dolly out
- Disconnect dolly air and electric lines
- Apply rig parking brakes
- Lower trailer landing gear
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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