What are the 3 main braking systems on a lorry?
The three main braking systems are called service brakes, secondary brakes and parking brakes. The service brake performs the primary function of stopping the vehicle when you depress the footbrake. The secondary brake system is for use in the event of failure of the service brake.
How does tractor trailer brakes work?
When one pushes the brake pedal, air is let into each brake chamber (Figure 5-2). Air pressure pushes the push rod out, moving the slack adjuster, thus twisting the brake cam shaft. This turns the S-cam. The S-cam forces the brake shoes away from one another and presses them against the inside of the brake drum.
How do you tell if brakes are out of adjustment?
Now, based on your previously determined size and type of brake chamber, check Measurement 2 against the correct adjustment limit for the brake chamber. If the applied pushrod stroke is longer than the adjustment limit, the brake is out of adjustment.
How do trucks check their brakes?
At the brake check area, drivers physically check each of the various components of the air brake system for wear, leaks, or damage. This check includes the air compressor, air drier, brake lines, trailer supply and emergency air hoses, and especially the brake drums and shoes.
What causes brake fade?
Brake fade tends to happen when the generated heat doesn’t have time to dissipate, such as when you repeatedly or continuously apply the brakes when driving fast. This excessive buildup of heat causes brakes to become less responsive.
What is the blue air line on a tractor trailer?
The blue line is the service brake air line. when the foot valve is applied to apply the tractor brakes, this applies the trailer brakes. There is also a third line, the electrical cord that supplies electric power for lights, signals and ABS brakes.
How should you check that your service brakes are working properly?
To test service brakes, you should brake firmly while moving slowly forward. The brakes are O.K. if you notice: a. The vehicle pulls to one side b.
How to determine the best braking performance of a tractor?
determine the best braking performance which could be achieved using a standard test vehicle, equipped with commercially available brakes, and employing state- of-the-art brake control systems. The effectiveness of the tractor brakes was varied by changing the wedge angles and brake chambers on the front brakes,
How to improve braking performance on trucks and buses?
Braking performance can be impr~ved significantly on trucks, buses, and tractsr-trailers through use of the advanced brake control systems, which were evaluated by test and/or simulation in this program. These systems, ranked in order of potential for improv- ing braking performance, are: a. wheel antilock system b.
How do I test the brakes on my bus?
TEST 1:Parking brake test. Start the bus and let the air pressure build to at least 90 psi. Step on the brake pedal and put the bus into gear. Slowly take your foot off the brake and gently press the accelerator. The bus should not move. TEST 2:Applied pressure test. (With parking brake released.) Turn the bus off.
How to measure the brake response time of tractor-trailer combinations?
To measure the brake response time of the tractor-trailer combinations pressure transducers were fitted to the output of the brake-control ( treadle) valve, and at each axle of the vehicle on which brakes were mounted, except only one transducer was mounted at a tandem axle.