Outline some typical maintenance and service procedures performed on hydraulic and airoverhydraulic brake systems. Chapter 33 fundamentals of hydraulic and airoverhydraulic. List the major components of an air over hydraulic braking system. Components of the air hydraulic system are trailermounted and consist of a compressed air storage tank, a control valve, an air chambermaster cylinder assembly, hydraulic lines and. The braking system can be classified into the mechanical brake, disc brake, hydraulic brake, powerassisted brake, air brake, electric, and hand brake system. Reservoir located below master cylinder restricting oil flow. Spring brake park brake air over hydraulic systems use vehicles air system to hold brake off when vehicle moving. The air over hydraulic has feel that is closer to an auto. Understand the operation, terms, and component functions of a hydraulic brake system. The airoverhydraulic brake system has an trailer brakes without applying the truck or tractor air over hydraulic power cylinder fig. 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 airactuatedhydraulic brake system 21 airboosthydraulic brake system 22. March 2003march 2003 fire apparatus driveroperator 1afire apparatus driveroperator 1a slide 21 air brake system most large, modern. Aug, 2018 hydraulic braking system is a type of braking system in which unlike the mechanical braking system, hydraulic fluid is used to transmit the brake pedal or brake lever force from the brake pedal or brake lever to the final drum shoes or disc caliper in order to achieve braking. Open center hydraulic power brake valve the open center power brake valve will provide.
The hand brake valve or independent trailer contains an air cylinder and a hydraulic cylinder in control valve, as shown in figures 344 and 346, tandem. If the motorhome is equipped with air over hydraulic. Mar 09, 2018 likewise, whenever the operator lets off the brake pedal in an air brake controlled vehicle, air pressure builds again and pushes the braking mechanism back out of the way. Air brake system air pressure protection valve prevents air horns air adjuncts from operating when the pressure in the air reservoir drops below 80 psi stop light switch turns on the brake lights when you apply the air brakes does with an electric switch that works by air pressure. However, on an air brake air is vented from the system when the brakes are released. Airoverhydraulic foundation brakes air brakes learning. There should be an open plug figure 4 threaded into the air booster housing. Where as you need additional braking, you push harder. As the name suggests, this type of braking system is a combination of parts of an air brake system and a hydraulic brake system. Maintenance and servicing of the air brake system 70 section summary questions 70 section nine pretrip air brake inspection 71 single unit not for air over hydraulic brake systems 72 combination unit.
Hydraulic brakes and airoverhydraulic brake systems. Residual check valves are usually used in drum brake systems to maintain slight residual pressure in the hydraulic brake system while the brake pedal is released. Jul 21, 2017 in this article, we will go through what an air over hydraulic brake system is, and how the system works. Air brake systems are more tolerant to small leaks. Air over hydraulic brake systems 21 section summary questions 24 section three how the basic system works 25 basic air brake system 26 oneway check valve 26 air pressure gauge 27 brake application gauge 27 low pressure warning device 27 stop brakelight switch 27 quick release valve 28 relay valve 28 manual front brake limiting valve 28. Air over hydraulic brake systems are subject to the following requirements and limitations. It uses both air and hydraulic compression to operate the brakes. 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. When actuation valve moved to apply brakes, air pressure is exhausted from spring. Pedal kickback check for dirt or foreign matter in hydraulic system. Air brake supplysystem 11 the components of an air brake system 12 compressor and governor 12 reservoirs 14 air dryer 15 safety valve 16 foot sectionvalve 16 brake dualchambers, slack adjusters. The smallest leak in a hydraulic system could result in brake failure.
An air brake system includes a compressor to generate more compressed air as. The air piston is of greater diameter than the hydraulic piston. Slowly depress the brake pedal and observe the gauges. The air over hydraulic system is a common application for trailers being towed by light and medium duty commercial vehicles equipped with air brake systems. I am looking at converting an air over hydraulic drum brake system on a military trailer m200a1 to electric over hydraulic brake system so i can safely and legally pull it with my truck and was wondering what would be the best solution.
Diesel engines on the other hand, do not create a vacuum and when most trucks were fitted with diesel engines in the 1970s and 80s, airoverhydraulic brakes were no longer feasible. Consider assemblies over kits servicing brakes using factory manufactured replacement assemblies rather than repair kits eliminates the potential for. If the motorhome has air over hydraulic brakes start the motorhome engine and allow the air brake system to completely charge up to operating pressure. The pressure is produced in a master cylinder and delivered to the disc calipers or drum wheel cylinders by tubes and flexible hoses. However, it is the trailer manufacturers responsibility to certify that their trailer meets. The rules for hvais require air brake systems including airoverhydraulic fitted to heavy vehicles to be inspected as part of the safety check. Air brake, and airhydraulic systems and hydromax conversions for the obsolete delco hypower. This is a simple explanation of a air over hydraulic brake system on a m200a1 trailer. Airoverhydraulic brake operation construction training manuals. An air control line connects the control valve to the compressed air cylinder. Power spring in unit mechanically moves brake components to apply brake.
The air brakes i now have, you have to hit hard first and then ease off. When the air control pressure gauge shows between 1 and 5 psi, the hydraulic pressure at the hydraulic inlet should not exceed 40 psi. When actuation valve moved to apply brakes, air pressure is exhausted from spring brake chamber. As in a conventional hydraulic brake system the residual check valve maintains a small amount of pressure in the hydraulic system when the brakes are released. Dec 28, 2017 a pneumatic brake or compressed air brake system is the type of brake system in which the compressed liquid fluid from the hydraulic system is replaced with the compressed air for applying pressure to the master cylinders piston which in turn presses the brake pads in order to stop or decelerate the vehicle. They can react badly with each other and corrode the brake system.
The hand brake valve or independent trailer contains. Excessive hydraulic pressure indicates a sticking relay piston or sticking control valve poppets. I made this video because when i was bidding on this trailer. 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. Residual check valves are usually used in drum brake systems to maintain slight. Versatile, highperformance air hydraulic actuators are designed to take advantage of available pressurized air sources to produce high hydraulic pressures. So, i hope you learned about the braking system and types of braking systems used in the automobile. 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 air over hydraulic brake systems 21 air actuated hydraulic brake system 21 air boost hydraulic brake system 22. The brake system model includes the controller, intensifier, brake lines, wheel cylinder. Check the condition of the foundation brakes, drums, linings, and brake shoes for binding. Bendix ah1b air hyd intensifier manual pdf download. Understand the operation of hydraulic and air brake systems. It is the brake system installers responsibility to insure compatibility between towing vehicles and trailer actuation. In this article, we will go through what an air over hydraulic brake system is, and how the system works.
The endorsement a is not required when operating class 3 or 5 vehicles licensed as a farm truck, or trucks with air over hydraulic brakes. The following definitions will help one understand the problems resulting from air in hydraulic systems. It is the brake system installers responsibility to insure compatibility between towing vehicles and trailer actuation systems. Diesel engines on the other hand, do not create a vacuum and when most trucks were fitted with diesel engines in the 1970s and 80s, air over hydraulic brakes were no longer feasible. Air brake parts bludot inc trailer braking systems. Air over hydraulic brakes, a simple explanation on a military trailer. Air over hydraulic brake systems contain an air over hydraulic power cylinder. Boosted brake circuits are those systems where the brake actuation effort is assisted by hydraulic, air, or vacuum. Offhighway safety air over hydraulic actuators wabco emea. The basic hydraulic brake system hydraulic brake systems guide page 7. Identify the major components of hydraulic, air, and air overhydraulic brake systems.
It is a kind of friction brake where instead of hydraulic fluid, air is used as the compression media for brake pads. Bendix ah4 air hyd intensifier manual pdf download. Identify the major components of hydraulic, air, and airoverhydraulic brake systems. Understand the operation of an antilock braking system. Air brakes are used on heavy vehicles because they have proven they are capable of stopping these vehicles safely. Free air is that trapped in a system, but not totally in contact with a fluid.
Various combinations of airhydraulic, eh, or vacuumhydraulic and tow vehicle systems can allow. View and download bendix ah1b air hyd intensifier manual online. Jul 17, 2015 this describes the operation explaining friction stoppage by compressed gas pressing on a piston to apply the force to the pads required to stop a moving veh. Hydraulic brake system and trailer brake inspection. Converting military trailer air over hydraulic drum brakes to. Before replacing the booster, remove the master cylinder to clean any dirt out. Find the main brake air booster housing figure 4, which is typically located near the front axle. Ah1b air hyd intensifier automobile parts pdf manual download. If the motorhome is equipped with air over hydraulic brakes an additional amount of air line part number 450700 may be required.
Outline some typical maintenance and service procedures performed on hydraulic and air over hydraulic brake systems. Consider assemblies over kits servicing brakes using factory manufactured replacement assemblies rather than repair kits eliminates the potential for brake system contamination and possible brake failure. An air brake system includes a compressor to generate more compressed air as needed. Modelling and analysis of an airoverhydraulic brake system. More information about the air brake system is in the chapter covering. The th series of airoverhydraulic abs trailer brake systems can be purchased in the following configurations. Vehicles with air over hydraulic full power systems since this is considered to be an air brake system by standards fmvsscmvss 121, the.
The air over hydraulic brake system has an trailer brakes without applying the truck or tractor air over hydraulic power cylinder fig. Air over hydraulic brakes, a simple explanation on a. List the major components of an airoverhydraulic braking system. Differences between air and hydraulic brakes godfrey brake. Versatile, highperformance airhydraulic actuators are designed to take advantage of available pressurized air sources to produce high hydraulic pressures. Converting military trailer air over hydraulic drum brakes to electric over hydraulic question. The air over hydraulic cylinder consists of an air cylinder and hydraulic cylinder in tandem, each fitted with a piston with a common piston rod between. Relocate reservoir above master cylinder to allow gravity feed.
The airoverhydraulic cylinder consists of an air cylinder and hydraulic cylinder in. Air braking system animation working tutorial youtube. Typical electric brake wiring diagram dexter parts. Identify the major components of hydraulic, air, and air over hydraulic brake systems. Th series air over hydraulic trailer kits with abs. Brakemaster 9100 and 9160 for motorhomes with air or air over hydraulic brakes installation instructions time tested time proven roadmaster, inc. Vacuum brakes in a vacuum brake system, depressing the brake pedal opens a valve between the power cylinder, which contains a piston, and the intake manifold to which the power cylinder is. High pressure piston 3 is not sealed against seat 4. The air and hydraulic cylinders each contain a piston and common rod. However, on an air brake air is vented from the system when the brakes are released and the reserve of compressed air must be replenished. Understand the hydraulic and mechanical principles of a brake system. This form of brake is analogous to an air brake system but with hydraulic fluid as the working medium rather than air. Vib 21 test procedure for mercedesbenz airoverhydraulic brake.
Ideal for brake applications in the construction, material handling, mining, forestry and farming industries as well as many other industrial applications. The airoverhydraulic brake system has an trailer brakes without applying the truck or tractor airoverhydraulic power cylinder fig. The chief advantage of air brakes over hydraulic brakes is their combination of stopping power and inherent safety. Airoverhydraulic brake systems contain an airoverhydraulic power cylinder. Th6000 series this system is designed to conform to all current fmvss 571. 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. This cylinder has both an air cylinder and a hydraulic cylinder inside, which work in tandem with each other. Differences between air and hydraulic brakes godfrey. Spring brake park brake airoverhydraulic systems use vehicles air system to hold brake off when vehicle moving. Likewise, whenever the operator lets off the brake pedal in an air brakecontrolled vehicle, air pressure builds again and pushes the braking mechanism back out of the way. The air cylinders piston is a larger diameter than the hydraulic cylinders piston.
Pbr offers a range of replacement product solutions including hydraulic cylinders and brake calipers including loaded calipers. The following requirements apply to vehicles with air brake and airoverhydraulic brake systems. Ordnance maintenance hydraulic brakes wagner lockheed brake has been left on, causing overheating and boiling or gassing of the brake fluid. 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. To operate an air brake system, diesel motors had to be fitted with an air compressor, and once fitted, a pure air brake system simply made sense. Residual pressure may vary depending on the system application. The airoverhydraulic brake system has an trailer brakes without applying the. Troubleshooting air brake system flashcards quizlet. None of the different types of brake fluids should be mixed.