Update Already Graded A
Modulating valve - ANSWER>>Control handle on the dashboard that may be used to apply
spring brakes gradually
Some vehicles have a separate air tank that can be used to release the - ANSWER>>Spring
brake
What does the tractor protection valve do - ANSWER>>Keeps air in the tractor or truck brake
system should the trailer and break away or develop a bad leak
The tractor protection valve the I'll close automatically if - ANSWER>>Air pressure is
low(range of 20-45psi)
Every combination has two air lines - ANSWER>>The service line and the emergency line
What are coupling devices used to connect the service and emergency air lines from the truck or tractor
to the trailer - ANSWER>>Glad hands
You need at least what tread on the front tires and what thread on the rear tires -
ANSWER>>4/32inch in front
2/32inch in rear
Steering wheel play of what degree can make it hard to steer - ANSWER>>10 degrees or two
inches
If more than one-forth or more leaf springs are leaking - ANSWER>>It will put the vehicle out
of service
What warning devices for parked vehicles - ANSWER>>Three reflective warning triangles, or 6
fuses or 3 liquid burning flares
, What should the Pressure build in three minutes and when does the governor cutout -
ANSWER>>Pressure should build from 50psi to 90 psi in 3minutes. Governor cut out at 120-
140psi
Safety equipment - ANSWER>>Spare electrical fuses unless vehicle has circuit breakers, three
red reflective triangles or three red burning flares
Proper idle and operating Oil pressure - ANSWER>>5-20 psi
Operating 35-75psi
Testing for hydraulic leaks - ANSWER>>Pump the break pedal three times then apply firm
pressure and hold for 5 seconds the pedal should not move if it does something is wrong
When should drivers inspect trucks and cargo? B - ANSWER>>They must inspect the
securement of cargo within the first 50 miles of a trip and every 150 miles or three hours
whichever comes first
Road speed - ANSWER>>Mph
Engine speed - ANSWER>>Rpm
Retarders - ANSWER>>Help slow a vehicle
Four basic types of Retarders - ANSWER>>Exhaust,engine, hydraulic, and electric
When should you turn the retarder off? - ANSWER>>When your drive wheels have poor traction
you should turn off it in icy snowy or wet conditions.
How far should you look ahead - ANSWER>>About 12-15 seconds at lower speeds about a block
at higher speeds about a quarter mile