What is the reason that air tanks must be drained?
To prevent too much moisture and oil from collecting, the air tanks must be drained regularly. Air pressure gauges indicate air pressure in the vehicle’s dual service (primary and secondary) air tanks. Safety valves prevent over-pressure of the air brake system.
Why must air tanks be drained?
Why must air tanks be drained? Water and compressor oil can get inside of the tank and can freeze in cold weather and cause brake failure. When the air pressure is removed the springs put on the brakes. A parking brake control in the cab allows the driver to let the air out of the brakes.
What is the maximum leakage rate?
6. What are the maximum leakage rates? Less than four psi in one minute for single vehicles and less than eight psi in one minute for combination vehicles. Less than two psi in one minute for single vehicles and less than three psi in one minute for combination vehicles.
How should you check that your service brakes are working properly?
How should you check that your service brakes are working properly? Wait for normal air pressure, release the parking brake, move the truck forward slowly, and apply the brake pedal firmly. The braking power of the spring brakes: Depends on the services brakes being in adjustment.
Why must air tanks be drained quizlet?
Terms in this set (19) Why must air tanks be drained? Compressed air usually has some water and some compressor oil in it, which is bad for the air brake system. They must be held on by mechanical force because air pressure can eventually leak away.
Why do truck drivers release air?
Brake Application – It is the release of pressurized air that causes brakes to deploy. The more air released, the more solidly brake pads grip their rotors. That means the application of the brake pedal essentially releases air from the pressurized tank.
What is a slack adjuster?
Slack adjusters are mechanical links between the brake-chamber push rod and the camshaft on cam type brakes. Slack adjusters are not used with wedge-type brakes. Slack adjusters are used to manually (Fig. 53) maintain proper brake chamber stroke and lining-to-drum clearance during normal operation.
How should you test the low pressure warning signal?
Test low pressure warning signal: Turn the electrical power on, and step on and off the brake pedal to reduce air tank pressure. The low air pressure warning signal must come on before the pressure drops to less than 60 psi in the air tank, or the tank with the lowest air pressure in dual air systems.
What is the first thing you should do when a low air pressure warning comes on?
The first thing to do when a low air pressure warning comes on is: Stop and safely park as soon as possible. The braking power of the spring brakes: Depends on the adjustment of the service brakes.
How long should it take to build air pressure?
45 seconds
At what PSI do air brakes lock up?
60 psi
Why do air brakes lock up?
The most common causes are incorrect or malfunctioning relay valves. Other causes include air leaks, air system contamination, a front-axle-limiting valve and excessive use of the trolley valve. Timing imbalance occurs when some brakes receive air faster than others.
At what PSI is the safety valve set to open?
150 psi
How much psi should my truck tires have?
Major tire makers’ load & inflation tables indicate that to support a 12,000-pound steer axle load (6,000 pounds per tire), a 22.5-inch low-profile load-range G tire should be inflated to at least 110 psi. Each of the manufacturer’s tables indicates 110 psi is necessary for a load of 6,175 pounds.
Should all 4 tires be the same PSI?
Also can lead to vehicle instability problems, since the tires are designed to flex, but uneven tire pressures causes the tires to flex differently. Tires on the same axle, like both fronts, have the same recommended tire pressure and it is not unusual to see different recommended pressures from front to rear.
How much does tire psi go up after driving?
The rule of thumb (best understood as our American counterparts put it) is that tire pressure will go up approximately one pound per square inch (PSI) for every 10 Fahrenheit increase in temperature.
What happens if you put too much air in your car tire?
Excessive air pressure can also distort the shape of the tire, leading to decreased traction and increased wear and tear down the center of the tire. It means center tread wear, an uncomfortable ride, and increased risk for a blowout.
What do you do when your tire has low pressure?
If too low, continue to add air in short bursts and recheck. If you add too much air, let some out by pressing the pin in the center of the tire valve with the back of the air hose nozzle or your tire gauge. Generally, the tire will let out approximately one psi for every three seconds the pin is depressed.