Air brake system troubleshooting low pressure switch will not operate at pressures below 60 psi buzzer or light will not operate indash gauge improper reading twoway check valve front or rear brake reservoir loses air pressure twoway check valve foot valve leaks at exhaust port when hand valve is applied. Here are a few great fault finding tips that will go a long way in finding and fixing the problem with your brakes. Cdl training how to pass air brakes exam driving academy part 1 duration. These lines connect the air brake system together and can crack, chafe or become loose due to vibrations, all of which can cause air leaks. A diagnostic system for air brakes in commercial vehicles. With the introduction of spring brakes, anticompounding and 121 air brake systems, because a valve is leaking air out of its exhaust, does. This equip ment employs as the major components a 26c brake valve, a 26f. Air brake systems are widely used in commercial vehicles such as trucks, tractortrailers. The guide consists of an introduction to air brake charging system components, a table showing recommended vehicle maintenance schedules, and a troubleshooting symptom and remedy section with tests to diagnose most charging system problems. Section two the components of an air brake system 11 the components of an air brake system 12 compressor and governor 12 reservoirs 14 air dryer 15 safety valve 16 foot valve 16 brake chambers, slack adjusters and brake lining 16 wedge brakes 20 disc brakes 21 airoverhydraulic brake systems 21 section summary questions 24 section three. Truck haldex brake products corporation 10930 north pomona.
A compressor to pump air with a governor to control it. If you want to drive a truck or bus with air brakes, or pull a trailer with air brakes, you need to read this section. Brake lag the time air takes to travel through a properly maintained air brake system, about 410 of a second. Dec 29, 2011 visually inspect air brake lines, especially if you notice a slow buildup of air pressure. The parts of an air brake system georgia commercial drivers. There is air leaking out of one of the rear brake diaphragms only when the brake pedal is depressed.
Some automated manual transmissions rely on pneumatic controls. Each system has its own air tanks, hoses, lines, etc. Driving academy car and cdl truck driving school 90,489 views. One system typically operates the regular brakes on the rear axle or axles. The study of this manual, along with practical instruction, is recommended to persons who ar e p r eparing for the completion of the air brake. Basic air brake system schematics total truck parts. And these days, theres no typical air brake system they can be highly.
If a spring brake is leaking from the the spring brake to the service brake side, that air will travel back up the service line and out the exhaust of the next valve back. Service parts 1200 series air dryers instructions for. A dual air brake system has 2 separate air brake systems, which use a single set of brake controls. Braking distance the actual distance a vehicle travels after the brake is applied until the vehicle stops. We have tracked down and corrected several air leaks on the old girl but still have one giant problem. A bad master cylinder can introduce air into the lines, as can a failure at a caliper or wheel cylinder. Printed on recycled paper checklist 2 if there is excessive leakage in the supply side of the pneumatic system, one or more. These moderately priced programs are available in 35 mm slide, v. How to determine air brake adjustmentappliedpry bar.
If an enclosed vacuum system or brake washing equipment is not availabl e, employers may. The most important factor in trailer troubleshooting is to determine if the malfunction is in the vehicles parking brake system or the service brake system. The governor controls when the air compressor will. An animation showing the workings of a tractorstrucks primary air brake system. May 10, 2011 an animation showing the workings of a tractorstrucks primary air brake system. Federal motor vehicle safety standard 121 dictates how this is to be done for overtheroad vehicles. Governor may be mounted on the air dryer as illustrated, on the compressor, or remotely. The wheel hub and brake assembly components should be thoroughly wetted to suppress dust before the brake shoes or brake pads are remov wiped. Additional airbrake system information bendix audiovisual programs bendix offers several audiovisual programs on many bendix airbrake devices and systems. With the introduction of spring brakes, anticompounding and 121 air brake systems, because a valve is leaking air out of its exhaust, does not mean the valve is at fault.
Considerable force is available for braking since the operating pressure is as high as 110 pounds per square inch. Troubleshooting air brake system flashcards quizlet. Air brake system anatomy understanding the three components of a commercial vehicle air brake system is crucial to diagnosing and repairing complex brake problems. If an enclosed vacuum system or brake washing equipment is not available, employers may. The wheel hub and brake assembly components should be thoroughly wetted to suppress dust before the brake shoes or brake pads are removed. May 28, 2015 cdl training how to pass air brakes exam driving academy part 1 duration.
Air brake system priority a pressure switch or transducer installed in the supply tank controls the ctis usage of air. Fault finding solving your air brake problems part 1 jmr. Advanced troubleshooting guide for air brake compressors. Mar 08, 2018 air brake system is a type of braking system generally used in heavy commercial vehicles or vehicles which require some really powerful and efficient braking system. If the vehicle is equipped with an adis air dryer system or a dryer reservoir module, be sure to drain the purge reservoir.
A basic air brake system capable of stopping a vehicle has five main components. Chock wheels repair and replace items as necessary. The study of this manual, along with practical instruction, is recommended to persons who are p reparing for the completion of. Trailer systems troubleshooting guide how to use this chart the purpose of the chart is to help you solve a specific problem in the pneumatic portion of a trailer air brake system with the assumption the foundation brake components and tractor pneumatics are in good repair. Therefore, the air air brake system of the towing vehicle must be in good condition. The 26l brake equipment is a combination automatic and independent locomotive brake of modern design which incorporates all of the operating features necessary for the control of freight and passenger train braking systems. Service parts 1200 series air dryers instructions for use on. Each commercial motor vehicle manufactured on or after october 20, 1994, and equipped with an air brake system, shall meet the automatic brake adjustment system requirements of federal motor vehicle safety standard no. Brake hydraulics are a sealed system, so there should not be air in the lines, but if after service you have a sponge pedal that is the most likely cause. Bendix air brake system troubleshooting 1800 air brake 18002472725 attend bendix brake school or visit brake for air brake system and product training. Haldex dolly operational air system tests required fixtures for testing.
The suspension draws air from these tanks through protection valves. The total system size is the sum of all the air tanks to be. This protects the vehicle air brake systems by helping to maintaining a safe level of air pressure the higher appropriate pressure. These valves protect the braking system from loss of air due to engine failure or failures in the suspension system. Section 5 air brakes page 1 section 5 air brakes this section covers air brake system parts dual air brake systems inspecting air brakes using air brakes this section tells you about air brakes. Install an air pressure gauge in the control valve housing and a hydraulic gauge at both the hydraulic fluid inlet line and the hydraulic brake line output port. Check the alcohol container and fill up as necessary, every day during cold weather. Truck haldex brake products corporation 10930 north. The air brake system of a trailer is entirely dependent upon the air brake system of the towing vehicle for its air supply and control. Weighing the costs and benefits of air disc brakes despite maintenance and pad life advantages, price remains the biggest hurdle to air disc brake adoption.
None of the different types of brake fluids should be mixed. Visually inspect air brake lines, especially if you notice a slow buildup of air pressure. Some air brake systems have an alcohol evaporator to put alcohol into the air system. Bendix air brake system troubleshooting 1800airbrake 18002472725 attend bendix brake school or visit for air brake system and product training. For instance, if the tractor has a total air system of 6000 in 3 supply 900 in 3, primary 3200 in 3, secondary 1900 in 3 and it pulls a lead single trailer with 1400 in 3, a single axle dolly with 1400 in 3, and a. The parts of an air brake system georgia commercial. It is a kind of friction brake where instead of hydraulicfluid, air is used as the compression media for brake pads. Air brake system is a type of braking system generally used in heavy commercial vehicles or vehicles which require some really powerful and efficient braking system.
The purpose of this book is to help you construct meritor wabco truck and tractor air systems. Ice inside the system can make the brakes stop working. The line from the compressor to the dryer, or hot line, can become plugged with carbon deposits. Automatic slack adjuster asa and air brake chamber. Air system valve troubleshooting and replacement maintenance. We will cover and discuss the three subsystems of the air brake system operation, inspection. These diagrams are provided for basic identification only. The charging, air treatment and storage system the charging, air treatment and storage system 8.
Bendix commercial vehicle systems bendix wingman advanced. All modern cars come with sophisticated antilock braking systems abs and brake based stability control, which complicates some aspects of troubleshooting and repair, but those systems will inform you when there is a problem and default to the old, simple system. The study of this manual, along with practical instruction, is recommended to persons who ar. This helps to reduce the risk of ice in air brake valves and other parts during cold weather. Pdf a diagnostic system for air brakes in commercial vehicles.
The purpose of an air brake system on heavy duty vehicles is to convert air pressure to mechanical energy to activate the foundation brakes. Brake and rear brake reservoirs to feed park control valve rear tank bleeddown also bleeds fron or vice versa. Most heavyduty vehicles use dual air brake systems for safety. If the problem is neither air system is working, the fault may be mechanical. This distance depends on the ability of the lining to produce friction, the. Requirements for air brake endorsement must complete an air brake written test. Application of air brakes becomes a necessity in case of. Replace as needed air dryer air leaking constantly from purge valve purge valve seal damaged. Air brake system troubleshooting page 2 steelsoldiers. Index and precautions device index 2 handbook section index 3 general precautions 4 glossary 7276 section 1.
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