Truck Tractor Air Brake Flashcards
When the compressor is in its. Unloaded cycle
The inlet valves are held open
On compression stroke the inlet valve is
Closed and the discharge valve is open
The governor controls maximum air system pressure by
Putting the compressor in the unloaded cycle
When does an automatic drain valve drain moisture and contamination from the reservoir
When there is any drop in reservoir pressure
Air brake antifreeze is used in the air brake system to
Prevent Moisture in the system from freezing
Desiccant type air dryers rely on
Beads that adsorb moisture vapor from the air stream
Why are single check valves installed on the primary and secondary service reservoirs
To prevent air loss in the event of a failure in the other reservoirs
The function of the safety valve is to
Limit air pressure buildup in the event of a governor failure
CMVSS 121 states the minimum pressure at which the low pressure warning devices must warn the operator is
60 PSI
Nylon airbrake tubing should not be used where it may be exposed to
High temperatures,abrasion and wear, excessive movement
The function of the relay valve in the primary brake circuit is to speed up the
Application and release of the primary service brakes
I type 24 brake chamber has an area of
24 square inches
During normal brake applications, the secondary section of the dual circuit brake valve is applied by
Primary service air pressure
The function of the quick release valve in the secondary break circuit is to
Speed up the release of the secondary service brakes
The dual circuit brake valve holds it’s inlet and exhaust valves closed
When the valve is in its balanced position
What are the 5 air systems on a truck/tractor?
- Supply
- Primary service
- Secondary service
- Park/emerg.
- Trailer control
What are there 3 major components of supply system?
- Compressor
- Dryer
- Governor
When a compressor is building air in system is is said to be in what cycle?
Loaded cycle
The purpose of governor is to?
Control compressor cut-in and cut-out pressure
The primary brake system is used to supply what brakes.
Drive axle(s) brakes
Brake valves are commonly referred to as?
Treadle valve
Treadle valves can be either ____ mounted, or _____ mounted?
- Floor
2. Firewall
In treadle valve what system is closest to pedal?
Primary
What are two types of brake chambers?
- Service
2. Spring brake
During normal brake application what applies secondary section of the dual-circuit brake valve?
Primary service air pressure.
