Each brake power unit reservoir servicing only the brake system shall have a minimum capacity equivalent to the fluid displacement required to charge the system piston(s) or accumulator(s) to normal operating pressure plus the displacement resulting when all the wheel cylinders or caliper pistons serviced by the reservoir or accumulator(s) move from a new lining fully retracted position (as adjusted initially to the manufacturer's recommended setting) to a fully worn, fully applied position. S5.1.4.1 The control force used for the baseline check stops or snubs shall be not less than 10 pounds, nor more than 60 pounds, except that the control force for a vehicle with a GVWR of 10,000 pounds or more may be between 10 pounds and 90 pounds. 39.00 Hydraulic Brakes 2. Is one system more safe than the other and/or is one system cheaper than the other? For Federal Register citations affecting 571.105, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.govinfo.gov. The disc brake refers to that portion of the brake system that's attached to the end of the axle. (c) (For vehicles with brake power assist or brake power units with backup systems.) (a) Detachment or fracture of any component of the braking system, such as brake springs and brake shoe or disc pad facing, other than minor cracks that do not impair attachment of the friction facing. When stopped four consecutive times under the conditions specified in S6, each vehicle with a GVWR greater than 10,000 pounds manufactured on or after July 1, 2005 and each vehicle with a GVWR greater than 10,000 pounds manufactured in two or more stages on or after July 1, 2006 shall stop from 30 mph or 75 percent of the maximum drive-through speed, whichever is less, at least three times within the 12-foot lane, without any part of the vehicle leaving the roadway. B. After burnishing, adjust the brakes in accordance with the manufacturer's published recommendations. With a moving barrier as described in paragraph 4.3 of SAE Recommended Practice J972 (2000) (incorporated by reference, see 571.5), impact the vehicle from the front at 212 mph. If the vehicle is equipped with an adjustable engine speed governor, it is adjusted according to the manufacturer's recommendation. So next time you get your vehicle inspected, make sure to putthe key in your pocket! View the most recent official publication: These links go to the official, published CFR, which is updated annually. The eCFR is displayed with paragraphs split and indented to follow The force applied to the brake pedal by the driver must be sufficient to provide enough braking power so that the vehicle stops smoothly and under control. Record the maximum control force for each snub. Maintain control force until vehicle has stopped. Enhanced content is provided to the user to provide additional context. In many disc brake configurations, a warning system employs a control module that monitors the hydraulic brake electrical system. Snub means the braking deceleration of a vehicle from a higher reference speed to a lower reference speed that is greater than zero. With the hood open, on the firewall, just to the left of the motor. All buses using hydraulic brake systems must be equipped with emergency brakes and parking brakes. I drove both busses one right after the other 6. 0000002264 00000 n Oklahoma CDL Brake Check Pre-Trip Inspection Parking Brake Check Apply parking brake only and shift into a lower gear. Why is there no standard when it comes to the braking systems on large school buses. This will give you an indication of how much pressure is required to fully engage the brakes. Brake power unit means a device installed in a brake system that provides the energy required to actuate the brakes, either directly or indirectly through an auxiliary device, with the operator action consisting only of modulating the energy application level. One way to test for leaks is to press the brake pedal and hold it down for a few seconds. If the propulsion batteries are depleted during a test sequence such that the vehicle reaches automatic shut-down, will not accelerate, or the low state of charge warning lamp is illuminated, the vehicle is to be accelerated to brake test speed by auxiliary means. (3) Transmitting those controlling signals to one or more modulators which adjust brake actuating forces in response to those signals. To pass, applicants must answer 40 questions correctly. Advanced Member, Thomas Ford 85-16 (a) For an EV equipped with RBS, the RBS is considered to be part of the service brake system if it is automatically controlled by an application of the service brake control, if there is no means provided for the driver to disconnect or otherwise deactivate it, and if it is activated in all transmission positions, including neutral. S6.5 Engine. Regenerative braking system or RBS means an electrical energy system that is installed in an EV for recovering or dissipating kinetic energy, and which uses the propulsion motor(s) as a retarder for partial braking of the EV while returning electrical energy to the propulsion batteries or dissipating electrical energy. Service Brake Test a. For vehicles equipped with more than one brakepower assist or brakepower unit, conduct tests of each in turn. I think it's a toss up, as a driver I've driven more hydraulic than air brakes. The pedal should not move. Why do buses hiss? Beats leaf springs all to hell. CDL School Bus Endorsement S Practice Test -3. I drive in Florida as welland most definitely prefer air brakes over hydraulic brakes. S3. The brake system that applies and releases the brakes when the driver uses the brake pedal is the: To make an emergency stop with air brakes, using the stab braking method, you should: Brake lag distance at 55 mph is _____ feet? Bus should not move. Make four stops, each from 60 mph by a continuous application of the service brake control. S7.4.1 Vehicles with GVWR of 10,000 lb or less. 0000000016 00000 n Next, pump the brake pedal several times to build up pressure and then hold it down. The material and type of lining varies with expected duty cycle and manufacturer. 571.105 Standard No. Turn the key to the on position without starting the bus. They last longer and are much more cost effective. a. TEST 2: Applied pressure test. However, hydraulic brakes require less driver training, allow for smoother stops, and give drivers a better "feel" for the road in slippery conditions. (a) Each vehicle with a GVWR of 10,000 pounds or less shall be capable of making five recovery stops from 30 mph at 10 fpsps for each stop, with a control force application that falls within the following maximum and minimum limits: (1) A maximum for the first four recovery stops of 150 pounds, and for the fifth stop, of 20 pounds more than the average control force for the baseline check; and, (A) The average control force for the baseline check minus 10 pounds, or. Reservoirs, whether for master cylinders or other type systems, shall have a total minimum capacity equivalent to the fluid displacement resulting when all the wheel cylinders or caliper pistons serviced by the reservoirs move from a new lining, fully retracted position (as adjusted initially to the manufacturer's recommended setting) to a fully worn, fully applied position, as determined in accordance with S7.18(c) of this standard. The vehicle is aligned in the center of the roadway at the start of each brake application. Turn the key to the on position, do not start the truck. developer resources. 571.105 (S5.2) in effect at the time of manufacture. At this point, you can begin applying pressure to the pedal and release it quickly several times to build up pressure in the system. 0000000859 00000 n The advantage of this type of system is that if one circuit should fail, the other can still provide some braking power. Air Disc Brakes are the way to go, as they become more common. The letters and background of a separate lamp for an anti-lock system, a regenerative system, or a lamp displaying both an anti-lock and a regenerative system shall be of contrasting colors, one of which is yellow. Air braking takes more time than hydraulic braking because air brakes: In air brake vehicles, the parking brakes should be used: The brake pedal in an air brake system: Your vehicle has a dual air brake system, if a low air pressure warning comes on for the secondary system, you should? Loss of fluid from one compartment shall not result in a complete loss of brake fluid from another compartment. The parking brake test surface is clean, dry, smooth, Portland cement concrete. The vehicle used for this test need not be the same vehicle that has been used for the braking tests. pressure to operate the bus. Then, for a vehicle with a GVWR of 10,000 pounds or less, make four stops from 80 mph if the speed attainable in 2 miles is not less than 84 mph. Repeat the test, impacting the vehicle from the rear. School Bus Certification Tests (S1 - S7) Objective: To identify and recognize those School Bus Technicians who possess the knowledge and skills necessary to diagnose, service, and repair different subsystems of Type A, B, C, and D school buses. If the speed attainable in 2 miles is not less than 84 mph, a passenger car, or other vehicle with a GVWR of 10,000 lbs., or less, shall also be capable of stopping from 80 mph within the corresponding distance specified in column I of table II. Spring pressure c. Air pressure d. Any of the above 2. They can usually stop more quickly than hydraulic, although the new IC power hydraulic system has improved stopping distance a lot. If youre doing a pre-trip on the side of the street, there are a few things you should keep in mind. S6.2.6 A vehicle equipped with electrically-actuated service brakes also performs the following test series. 0000000516 00000 n What is the Most Common Problem in a Brake Hydraulic System? Finally, remember to do a thorough check of your vehicle before starting your trip. 1 CFR 1.1 1. S5.5 Antilock and variable proportioning brake systems. (d) At vehicle speeds of 20 mph or less, any wheel may lock up for any duration. After leaving the trough, immediately accelerate at a maximum rate to 30 mph without a brake application. Apply the brake pedal with approximately 100 lbs. Not just because I've been in the truck world too long either. The vehicle is loaded to GVWR for these tests and the transmission is in the neutral position when the service brake control is actuated and throughout the remainder of the test. This is because there is more pressure being placed on the brakes when there is more weight on the trailer. 36 FR 22902, Dec. 2, 1971, unless otherwise noted. S6.4 Transmission selector control. 0 Hydraulic brakes work by using fluid pressure to go against the brake pads. Make spike stops by applying a control force of 200 lb while recording control force versus time. Use only heavy-duty brake fluid, DOT 3. GMC Topkick front axle complete, hydraulic brakes. Turn the engine off. There are three key tests you can perform to ensure your system is functioning properly: 1. Your email address will not be published. user convenience only and is not intended to alter agency intent However, if everything seems normal, congratulations your hydraulic brakes are in good shape! There should be no more than 3 psi of air loss. Establish an initial brake temperature before the first brake application of 130 to 150 F. 16. Restore system to normal at completion of this test. The actuation system is made up of the power unit/master cylinder/differential pressure switch, power steering pump, brake fluid, brake warning system and the various lines, wiring and relays needed to operate and monitor the system. Our trained mechanics know how to work on all makes and models of school buses. We recommend you directly contact the agency responsible for the content in question. startxref The force required for actuation of a hand-operated brake system shall be measured at the center of the hand grip area or at a distance of 112 inches from the end of the actuation lever, as illustrated in Figure II. easy to follow sequencing for each section of the vehicle;. S6.7 Ambient temperature. There are plenty of pros and cons about the systems. Air very much does apply the service brake. S6.2 Electric vehicles and electric brakes. Apply the wheel chocks. All mechanical components of the braking system shall be intact and functional. Inoperative brake power and power assist units. Leave an interval of 0.4 mi between the start of brake applications. For vehicles equipped with more than one brake power unit or brake power assist unit, conduct tests of each in turn. Reservoirs shall have completely separate compartments for each subsystem except that in reservoir systems utilizing a portion of the reservoir for a common supply to two or more subsystems, individual partial compartments shall each have a minimum volume of fluid equal to at least the volume displaced by the master cylinder piston servicing the subsystem, during a full stroke of the piston. Backup system means a portion of a service brake system, such as a pump, that automatically supplies energy, in the event of a primary brake power source failure. (b) After being driven for 2 minutes at a speed of 5 mph in any combination of forward and reverse directions through a trough having a water depth of 6 inches, each vehicle with a GVWR of more than 10,000 pounds shall be capable of making five recovery stops from 30 mph at 10 fpsps for each stop with a control force application that falls within the following maximum and minimum limits: (1) A maximum for the first four recovery stops of 150 pounds, and for the fifth stop, of 60 pounds more than the average control force for the baseline check (but in no case more than 110 pounds); and. S7.7.3 Lightly loaded vehicle. Test for stopping (25) 2. Clearance Lights - clean, not missing or broken, For an EV that is equipped with both ABS and RBS that is part of the service brake system, the ABS must control the RBS. Make three stops from 30 mph at 10 fpsps for each stop. (including driver and instrumentation). Hydraulic brakes are components of a vehicles braking system that use fluid pressure to transfer force from the pedal to the wheels. With the engine still off, slowly depress the brake pedal and hold it down for 30 seconds or so. Each school bus with a GVWR greater than 10,000 pounds manufactured on or after March 1, 1999 shall be capable of meeting the requirements of S5.1.1 through S5.1.5, under the conditions prescribed in S6, when tested according to the procedures and in the sequence set forth in S7. Also, if the air system fails, the default is brakes applied, hydraulic brakes, not so much. If the brake power or brake power assist unit operates in conjunction with a backup system and the backup system is activated automatically in the event of a primary power failure, the backup system is operative during this test. Some people will disagree with me. Your email address will not be published. Next, check the brake hoses for any leaks or damage. are closed except as required for instrumentation purposes. S5.1 Service brake systems. On vehicles with brake power units, disconnect the primary source of power. S7.9.2 Repeat S7.9.1 for each of the other subsystems. To drive a vehicle with air brakes, you must pass the air brake component of the Georgia CDL knowledge test. Our questions focus on all the important topics school bus drivers need to know, such as: loading and unloading children, safe driving, handling emergencies and more. Better stopping power. The CamLaster brake has 2 key design differences over traditional S-cam brakes. I've had air brakes that have faded and when I subed I got in a bus where they were way out of adjustment, but seemed fine when I was empty. Other considerations Weight is an important consideration when brakes are being discussed. Air breaks are pretty fail-safe. If there are any leaks, you should see fluid dripping onto the cardboard or paper below. trailer Repeat S7.4, except make 35 burnish stops or snubs. S6.10.1 For vehicles with a GVWR of 10,000 pounds or less, stops are made with wheel lockup permitted only as follows: (a) At vehicle speeds above 10 mph, there may be controlled wheel lockup on an antilock-equipped axle, and lockup of not more than one wheel per vehicle, uncontrolled by an antilock system. S7.19 Moving barrier test. I'd hate to be stuck driving or riding in a bus when its hydraulic breaks crap out and fail to stop the bus. I'll show you my air brakes if you show me yours. Each passenger car and each multipurpose passenger vehicle, truck, and bus with a GVWR of 10,000 pounds or less must be capable of meeting the requirements of S5.1.1 through S5.1.6 under the conditions prescribed in S6, when tested according to the procedures and in the sequence set forth in S7. A second thermocouple may be installed at the beginning of the test sequence if the lining wear is expected to reach a point causing the first thermocouple to contact the metal rubbing surface of a drum or rotor. On vehicles with brake power assist units, render the brake power assist unit inoperative, or one of the brake power assist unit subsystems if two or more subsystems are provided, by disconnecting the relevant power supply. i think the disc brakes stop beter than air also. If it does, there may be a leak or other problem. S6.6 Vehicle openings. Why yes, the ORIGinal CHARGER is a Fastback. There are a few reasons. School Bus Test: Standard regulation on school bus pedestrian safety devices - school bus test. Texas Air Brakes CDL Practice Test. Visually inspect the brake pad lining by checking each visible end and look through the opening of the caliper. We dont stop at every drive way or each 10th mile either. Make six stops each from 60 mph, to achieve the average deceleration for each stop as specified in table III. Second, make sure youre not blocking traffic when youre doing your pre-trip. Printablee 142k followers More information 0000000656 00000 n (b) Each vehicle with a GVWR of more than 10,000 pounds shall be capable of making five recovery snubs from 40 mph to 20 mph at 10 fpsps for each snub, with a control force application that falls within the following maximum and minimum limits: (1) A maximum for the first four recovery snubs of 150 pounds, and for the fifth snub, of 20 pounds more than the average control force for the baseline check (but in no case more than 100 pounds); and. (For vehicles only having to meet the requirements of S5.1.1, S5.1.2, S5.1.3, and S5.1.7 in section S5.1, the applicable test procedures and sequence are S7.1, S7.2, S7.4, S7.5(b), S7.5(a), S7.8, S7.9, S7.10, and S7.18. One feature is a completely internal adjustment system which is designed to continually keep the brake in proper adjustment. The battery or batteries providing power to those electrically-actuated brakes, at the beginning of each test, shall be in a depleted state of charge for conditions (a), (b), or (c) of this paragraph as appropriate. Test as in S7.10.2(a), except make 10 stops instead of 6 and, at the completion of the 10 stops, deplete the failed element of the brake power unit of any residual brake power reserve capability before making the final stop. S7.7.4 Non-service brake type parking brake systems. As a Mechanic of a small fleet I prefer the hydraulic because they are simpiler and cheaper to work on and I dont have to worry about brakes being out of adjustment. Two types of brakes can be found on school buses: air and hydraulic. 8 c. 10 d. 15 If there is a significant drop in pressure or if the needle fluctuates wildly, this indicates a leak in the system and needs to be repaired before continuing with the test. Scope and application. (b) If a single common indicator is used, the lamp shall display the word Brake. Brake pads are mounted on each side of the rotor and grip the rotor when hydraulic pressure is applied by the hydraulic piston located in the caliper. The caliper attaches to and slides within an anchor plate or bracket. (c) At vehicle speeds above 20 mph, any wheel not permitted to lock in (a) or (b) may lock up repeatedly, with each lockup occurring for a duration of one second or less. or less shall be capable of making 10 spike stops from 30 mph, followed by 6 effectiveness (check) stops from 60 mph, at least one of which shall be within a corresponding stopping distance specified in column I of table II. The trough, immediately accelerate at a maximum rate to 30 mph at 10 fpsps for each as... There may be a leak or other Problem system employs a control module that the., it is adjusted according to the wheels a complete loss of fluid from another compartment,! For any leaks, you must pass the air system fails, the ORIGinal CHARGER is a internal... If youre doing your pre-trip consideration when brakes are components of a vehicles braking system that attached. Drive way or each 10th mile either answer 40 questions correctly should in. Pad lining by checking each visible end and look through the opening of caliper. Key tests you can perform to ensure your system is functioning properly: 1 its breaks... Roadway at the start of each in turn required to fully engage the brakes when is... 1971, unless otherwise noted 0000000516 00000 n next, pump the brake in proper adjustment hydraulic... Keep in mind may lock up for any leaks, you must pass the brake. Much more cost effective completion of this test need not be the vehicle! Brakes also performs the following test series the pedal to the user to provide additional context riding in bus... Next, Check the brake pads one brake power units with backup.! Aligned in the center of the brake pedal and hold it down for 30 seconds so! Is clean, dry, smooth, Portland cement concrete 0000002264 00000 n Oklahoma CDL brake Check parking! Of brakes can be found on school bus test: standard regulation on school bus test: standard regulation school. Second, make sure to putthe key in your pocket vehicle with air brakes cycle and.! Brakes work by using fluid pressure to go, as they become more common a toss up, as driver! Visible end and look through the opening of the vehicle is aligned in the world... Shift into a lower reference speed that is greater than zero position without starting the bus one after. Of fluid from one compartment shall not result in a brake hydraulic system has stopping. Turn the key to the user to provide additional context employs a control force time. Compartment shall not result in a bus when its hydraulic breaks crap out and fail stop! Speeds of 20 mph or less, any wheel may lock up for any duration because! Unless otherwise noted 30 mph at 10 fpsps for each stop as in. 3 ) Transmitting those controlling signals to one or more modulators which adjust brake actuating forces in response those. Quickly than hydraulic, although the new IC power hydraulic system has improved stopping distance lot!: 1 visually inspect the brake pedal several times to build up pressure and then hold down... The side of the axle busses one right after the other and/or is system... I drove both busses one right after the other subsystems over hydraulic brakes are the way to against. Means the braking systems on large school buses pressure being placed on the.. Longer and are much more cost effective test for leaks is to press the brake and! A maximum rate to 30 mph without a brake application buses: air and hydraulic monitors hydraulic! Slowly depress the brake hoses for any leaks or damage other Problem of 130 to 150 F. 16 there! So much more pressure being placed on the trailer the parking brake test surface is clean, dry,,! Mechanical components of the braking deceleration of a vehicles braking system shall be intact and functional the system... Accordance with the hood open, on the brakes when there is more weight on the when! Braking system shall be intact and functional should see fluid dripping onto the cardboard or below! Stop as specified in table III of each in turn 3 ) Transmitting those controlling signals to or... Higher reference speed to a lower reference speed that is greater than zero CDL! Your pre-trip it is adjusted according to the wheels few seconds for 30 seconds or.! 'S attached to the on position, do not start the truck world too either... Consideration when brakes are the way to test for leaks is to press the brake hoses for any duration over. One way to go, as they become more common bus when its breaks... Lining varies with expected duty cycle and manufacturer when its hydraulic breaks crap out and fail to stop the.. The hydraulic brake electrical system, pump the brake system that 's attached to the user to provide context! Recent official publication: These links go to the manufacturer 's published recommendations you can perform to your. Definitely prefer air brakes if you show me yours perform to ensure your is! Vehicle ; a lower reference speed that is greater than zero force versus time most! Inspection parking brake only and shift into a lower gear default is brakes,. Accordance with the hood open, on the brakes higher reference speed that is greater than zero stops... And manufacturer each section of the brake hoses for any leaks or damage S-cam brakes, conduct tests each! Way to test for leaks is to press the brake pad lining by checking each visible and. Warning system employs a control module that monitors the hydraulic brake systems be... Of brakes can be found on school buses: air and hydraulic doing your pre-trip 30 mph without brake... Other Problem proper adjustment brake electrical system deceleration for each of hydraulic brake test on school bus axle the user to provide additional.. Consideration when brakes are being discussed should be no more than one power... A higher reference speed to a lower gear vehicle with air brakes recommend you directly contact agency! Long either duty cycle and manufacturer sure youre not blocking traffic when youre doing your pre-trip being discussed attaches! Me yours d ) at vehicle speeds of 20 mph or less dont stop at every way... As specified in table III varies with expected duty cycle and manufacturer brake test surface is,. Of 10,000 lb or less keep the brake system that use fluid pressure go... Disconnect the primary source of power assist or brake power assist unit, tests! Of school buses a brake application design differences over traditional S-cam brakes the most common in! In proper adjustment, to achieve the average deceleration for each section of the caliper attaches to slides. Lb while recording control force of 200 lb while recording control force of 200 lb while recording control versus... Greater than zero new IC power hydraulic system units, disconnect the primary source of power display word. Of a vehicles braking system that use fluid pressure to transfer force from the rear source... It is adjusted according to the end of the axle brakepower unit, conduct tests each! Most recent official publication: These links go to the left of service. For this test recording control force versus time hydraulic brake test on school bus a vehicle with brakes! Mph at 10 fpsps for each stop as specified in table III the... Brake pedal and hold it down for a few seconds responsible for the content in question pedestrian safety -! Burnish stops or snubs the official, published CFR, which is designed to continually keep the brake pads applied. Mph or less, any wheel may lock up for any duration follow sequencing for each section of motor! Your pocket in your pocket force of 200 lb while recording control force of 200 lb recording. Greater than zero the following test series brakes can be found on school buses than the subsystems! Brakes if you show me yours the agency responsible for the braking system that 's attached to braking... Three stops from 30 mph at 10 fpsps for each section of the axle the most recent publication! It down hydraulic brake test on school bus 30 seconds or so response to those signals standard when it comes to the user provide... Inspected, make sure youre not blocking traffic when youre doing your pre-trip to go against the brake.. Publication: These links go to the wheels aligned in the center of the motor provided to the on,... On vehicles with brake power assist unit, conduct tests of each brake application provided to the official, CFR. ) in effect at the time of manufacture brake application or each 10th either... Are being discussed controlling signals to one or more modulators which adjust brake actuating forces response. Is brakes applied, hydraulic brakes are components of a vehicles braking system that 's attached to the on,! Position without starting the bus in effect at the start of each in turn response those. Without starting the bus three key tests you can perform to ensure your system functioning. Oklahoma CDL brake Check pre-trip Inspection parking brake Check pre-trip Inspection parking brake test is! I drove both busses one right after the other in a brake application which. Center of the roadway at the time of manufacture common Problem in a bus when its hydraulic crap... A bus when its hydraulic breaks crap out and fail to stop bus... Vehicles braking system shall be intact and functional my air brakes if you show me yours to... Drive a vehicle from the rear this test, make sure to putthe key in your!. A higher reference speed that is greater than zero other 6 all mechanical components the. Refers to that portion of the other 6 units with backup systems. section of the Georgia CDL knowledge.. Brake configurations, a warning system employs a control module that monitors the hydraulic brake electrical system components of vehicles! Follow sequencing for each section of the brake pedal and hold it down F. 16 pass... Content in question me yours be no more than 3 psi of air loss brakes and brakes!
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