hydraulic brake test on school bus

S5.1.2.3 For a vehicle manufactured with a service brake system in which the brake signal is transmitted electrically between the brake pedal and some or all of the foundation brakes, regardless of the means of actuation of the foundation brakes, the vehicle shall be capable of stopping from 60 mph within the corresponding distance specified in Column IV of Table II with any single failure in any circuit that electrically transmits the brake signal, and with all other systems intact. Once youve released the pedal, check for any leaks around fittings or connections. Make 500 snubs between 40 mph and 20 mph at a deceleration rate of 10 f.p.s.p.s. Repeat the test, impacting the vehicle from the rear. S5.1.7 Stability and control during braking. For an EV, the speed attainable in 2 miles is determined with the propulsion batteries at a state of charge of not less than 95 percent at the beginning of the run. 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. A school bus shall not a. S2. One way to test for leaks is to press the brake pedal and hold it down for a few seconds. Hydraulic brake system means a system that uses hydraulic fluid as a medium for transmitting force from a service brake control to the service brake, and that may incorporate a brake power assist unit, or a brake power unit. Top Member, ihthomas665spd Heres how to do a basic check: Start by checking the fluid level in the reservoir. Next, pump the brake pedal several times to build up pressure and then hold it down. (b) For EVs with RBS that is part of the service brake system, the tests in S7.10.1 or S7.10.2 are conducted with the RBS discontinued and all other systems intact. xref It's also important to lubricate the rails that the caliper moves upon to ensure consistent operation and also to guard against contamination by rust and dirt. To receive this license, applicants must pass a 50-question test. At this point, you can begin applying pressure to the pedal and release it quickly several times to build up pressure in the system. S7.4.1.2 Brake adjustment - post burnish. 0000004353 00000 n You are using an unsupported browser. See this. Pressure component means a brake system component that contains the brake system fluid and controls or senses the fluid pressure. For vehicles equipped with more than one brake power unit or brake power assist unit, conduct tests of each in turn. Each vehicle with electrically-actuated service brakes (brake power unit) shall comply with the requirements of S5.1.3.1 with any single electrical failure in the electrically-actuated service brakes and all other systems intact. exact, verbatim wording for each component that must be checked;. 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. S7.9 Service brake system test - partial failure. 1. Service on the single- or twin-piston caliper is essentially the same. Use a full brake application for the duration of the stop, with the clutch pedal depressed or the transmission selector control in the neutral position, for the duration of each stop. Hydraulic Brake Check Pump the brake pedal three times, then hold it down for five seconds. Maintain control force until vehicle has stopped. Your email address will not be published. Determine whether the brake system indicator lamp is activated when the RBS is disconnected. The most important thing is the amount of pressure that is being applied to the pedal. Average the maximum brake control force required for the three stops. For whatever reason, I feel more in control. (b) The parking mechanism must be engaged before the ignition key can be removed. Heres how to test your hydraulic brakes for leaks: 1. Negative for hydraulic brakes- Most brake fluid is hyrdoscopic, which lowers the boiling point of the fluid. By taking care of these things ahead of time, you can avoid potential issues later on. Any brake fluid or power steering fluid leak A 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. For this you will need to know the parts of a single and dual air brake system, how to inspect and use them. S7.7.1 Test procedure for requirements of S5.2.1 and S5.2.3. 6 b. 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. It can also cause corrosion in the brake system. This will give you the best traction possible and help keep your car from rolling. The indicator lamp shall be deactivated at the end of the check of lamp function unless there is a malfunction or a message about a malfunction that existed when the key switch was last turned to the off position. If batteries are replaced rather than recharged, each replacement battery shall be charged and measured for state of charge in accordance with these procedures. Unless otherwise specified, the force applied to a brake control is not less than 15 lb and not more than 150 lb. This content is from the eCFR and may include recent changes applied to the CFR. Antilock brake system or ABS means a portion of a service brake system that automatically controls the degree of rotational wheel slip during braking by: (1) Sensing the rate of angular rotation of the wheels; (2) Transmitting signals regarding the rate of wheel angular rotation to one or more controlling devices which interpret those signals and generate responsive controlling output signals; and. I Vote Air Brakes, I agree about that they lock up, and you can't move, instead of that I can't stop. 101 and/or this section and symbols may be provided for purposes of clarity. S7.9.4 (For vehicles with antilock and/or variable proportioning brake systems.) If a battery is replaced rather than recharged, the replacement battery is to be charged and measured for state of charge in accordance with these procedures. 105; Hydraulic and electric brake systems. to 200 F. (b) A drop in the level of brake fluid in any master cylinder reservoir compartment to less than the recommended safe level specified by the manufacturer or to one-fourth of the fluid capacity of that reservoir compartment, whichever is greater. You can If the speed attainable in 2 miles is not less than 99 mph, a passenger car shall, in addition, be capable of stopping from the applicable speed indicated below, within the corresponding distance specified in column I of table II. S7.4.1.1 Burnish. Still getting my feet wet and curious as to what people prefer in the long term from a maintenance perspective: hydraulic or air brakes? https://www.facebook.com/home.php?sk=group_212311114614&ap=1. S7.7.1.4 Following the application of the parking brake in accordance with S7.7.1.3, release all force on the service brake control and commence the measurement of time if the vehicle remains stationary. Step on the brake and hold the pedal down for one minute. Went there for test drive with another tech and connected laptop. Table I - Brake Test Procedure Sequence and Requirements, Table III - Inoperative Brake Power Assist and Brake Power Units. Its a 34' Freightliner Thomas. (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. Foot or service brakes distance shall, at all times, be . Advanced Member, BJ Henderson Then, for any vehicle, make six stops from 60 mph. The pedal should not move. Splash Guards/Mud Flaps - mounted, not damaged . %PDF-1.4 % (a) The service brake system for detachment or fracture of any components, such as brake springs and brake shoes or disc pad facing. This warning indicator shall, instead of meeting the requirements of S5.3.2 through S5.3.5, activate (while the vehicle remains capable of meeting the requirements of S5.1.2.2 and the ignition switch is in the on position) a continuous or intermittent audible signal and a flashing warning light, displaying the words STOP-BRAKE FAILURE in block capital letters not less than one-quarter of an inch in height. (c) A malfunction that affects the generation or transmission of response or control signals in an antilock brake system, or a total functional electrical failure in a variable proportioning brake system. S6.3 Tire inflation pressure. 41. S5.1.3.1 The service brakes on a vehicle equipped with one or more brake power assist units or brake power units, with one such unit inoperative and depleted of all reserve capability, shall be capable of stopping a vehicle from 60 mph within the corresponding distance specified in column IV of table II. If the hose fittings do not leak go to step 5. Please do not provide confidential Why do buses hiss? 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. The tractor protection valve Where I live (BC Canada) need a special addition to my license for air brakes so I went with hydraulic brakes on my bus. S7.7.1.6 Check the operation of the parking brake application indicator required by S5.3.1(d). (Engine may be run up in speed, then throttle closed quickly to attain maximum charge on vacuum assist units.) 3 2) Safety procedures usually require the bus driver to use wheel chocks during the air brake check. A vehicle shall be deemed to comply with the stopping distance requirements of S5.1 if at least one of the stops at each speed and load specified in each of S7.3, S7.5(b), S7.8, S7.9, S7.10, S7.15 and S7.17 (check stops) is made within a stopping distance that does not exceed the corresponding distance specified in Table II. There are a few reasons. Tail Lights/Brake Lights - clean, not missing or broken . If no recommendations are furnished, run the vehicle in an unburnished condition. startxref Effectively, the engine works backwards by creating negative torque. Clearance Lights - clean, not missing or broken, If there are no leaks in the system, you should see the needle on the pressure gauge rise steadily during this time. S6.7 Ambient temperature. After burnishing, adjust the brakes in accordance with the manufacturer's published recommendations. Fig. (With parking brake released.) Are their school bus drivers that prefer one over the other? S1. (c) Unlimited wheel lockup is allowed during spike stops (but not spike check stops), partial failure stops, and inoperative brake power or power assist unit stops. Friction facing tearout (complete detachment of lining) shall not exceed 10 percent of the lining on any single frictional element. (b) (For vehicles with brake power units with accumulator type systems.) . Tire inflation pressure is the pressure recommended by the vehicle manufacturer for the GVWR of the vehicle. A dual air brake system is one in which there are two separate circuits, each with its own reservoir, compressor, and brakes. 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. Leave an interval of 0.4 mi between the start of brake applications. 6 11 Make six stops each from 60 mph, to achieve the average deceleration for each stop as specified in table III. S7.10.1 Regular procedure. Make six stops from 60 mph with vehicle at lightly vehicle weight, or at the manufacturer's option for a vehicle with GVWR greater than 10,000 pounds, at lightly loaded vehicle weight plus not more than an additional 1,000 pounds for a roll bar structure on the vehicle. S5.4.1 Master cylinder reservoirs. %%EOF S5.1 Service brake systems. Drive 1 mi at 30 mph after the last fade stop, and immediately follow the recovery procedure specified in S7.11.3.1. S6.8 Wind velocity. Visually inspect the brake pad lining by checking each visible end and look through the opening of the caliper. (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. For S7.3, S7.5, S7.8, S7.15, S7.17, S7.11.1.2, S7.11.2.2, S7.11.3.2, and as required for S7.13, the transmission selector control is in neutral for all decelerations. The purpose of this standard is to insure safe braking performance under normal and emergency conditions. 0000000987 00000 n The service brakes of a vehicle equipped with one or more brake power assist units or brake power units with a backup system, with one brake power assist unit or brake power unit inoperative and depleted of all reserve capability and with only the backup system operating in the failed subsystem, shall be capable of stopping the vehicle from 60 mph in 15 consecutive stops at an average deceleration for each stop that is not lower than 12 fpsps (equivalent stopping distance 323 feet). Remove old certificate. Search & Navigation Periodic adjustment to manufacturer specifications is required. 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? S5.1.1.4 In the fourth effectiveness test, a vehicle with a GVWR of 10,000 pounds or less shall be capable of stopping from 30 and 60 mph within the corresponding distances specified in column I of table II. (d) The brake system indicator light(s), for compliance with operation in various key positions, lens color, labeling, and location, in accordance with S5.3. Use only heavy-duty brake fluid, DOT 3. S6.4 Transmission selector control. switch to drafting.ecfr.gov. This will help keep your car from rolling as well, but should only be used as a last resort. the hierarchy of the document. A straight truck or bus air brake system would not leak at a rate of more than how many PSI per . Indirectly Controlled Wheel means a wheel at which the degree of rotational wheel slip is not sensed, but at which the modulator of an antilock braking system adjusts its brake actuating forces in response to signals from one or more sensed wheels. (Only for vehicles that have been tested according to S7.7.2.) Comments that include personal YOU must set the parking brake immediately C. your service brakes will still work, using extra leg power 17. Check the fluid level in the hydraulic brake reservoir. It is not an official legal edition of the CFR. FAR). Restore system to normal at completion of this test. easy to follow sequencing for each section of the vehicle;. Allow a braking distance interval of 1 mi. A vehicle with a GVWR of 10,000 pounds or less may have a single common indicator lamp. In Florida, anything that has an Air Brake option is so equipped. Other considerations Weight is an important consideration when brakes are being discussed. 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. With the engine still off, slowly depress the brake pedal and hold it down for 30 seconds or so. If not, your brakes are fine! When the transmission selector control is required to be in neutral for a deceleration, a stop or snub must be obtained by the following procedures: (b) Close the throttle and coast in gear to approximately 2 mph above the test speed; (d) When the test speed is reached, apply the service brakes. 5 - 10 Enhanced content is provided to the user to provide additional context. 2. attacks or slurs, hate speech, demonstrably false information, excessive profanity, or that are thinly veiled promotions for a product, will not be approved. Some have air brakes but most operators have hydraulic.One of the reasons they use against air brakes is because there is such a turn over of drivers they don't want to provide the extra training. However, if you have the key in your pocket during the inspection, they wont be able to test it properly. 1200-1500 RPM. Printablee 142k followers More information Why is there no standard when it comes to the braking systems on large school buses. Make spike stops by applying a control force of 200 lb while recording control force versus time. The Georgia CDL test consists of 50 questions. If you would like to comment on the current content, please use the 'Content Feedback' button below for instructions on contacting the issuing agency. The parking brake test surface is clean, dry, smooth, Portland cement concrete. S5.1.3.3 Brake power units. Comments are moderated and may not appear for 24 hours or more. If you have questions or comments regarding a published document please You also need to make sure that there is no air in the system, as this can cause problems with braking performance. S7.7 Parking brake test. S5.5 Antilock and variable proportioning brake systems. 58 0 obj<>stream or less, unloaded vehicle weight plus 400 lbs. Control force readings may be terminated when vehicle speed falls to 5 mph. 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. 0000002025 00000 n The module activates the "Brake Pressure" indicator light and a buzzer sounds when it senses a malfunction. (b) For vehicles manufactured on and after September 1, 1999 with GVWRs greater than 10,000 lbs, each message about the existence of a malfunction, as described in S5.3.1(c), shall be stored in the antilock brake system after the ignition switch is turned to the off position and the indicator lamp shall be automatically reactivated when the ignition switch is again turned to the on position. Burnish stops are conducted on any surface. If the pedal sinks to the floor, there may be a leak in the system. FY TP-131-SB1 pt1. I just bought my first School bus and it has air brakes. Peak friction coefficient or PFC means the ratio of the maximum value of braking test wheel longitudinal force to the simultaneous vertical force occurring prior to wheel lockup, as the braking torque is progressively increased. There's a reason big rigs have air brakes! Tandem axle means a group of two or more axles placed in close arrangement one behind the other with the center lines of adjacent axles not more than 72 inches apart. If there are any leaks, you should see fluid dripping onto the cardboard or paper below. Bendix Hydro-Max Brake System Inspecting 1. Step 7: Start Engine and Check Brake System Test for hydraulic leaks: If the vehicle has hydraulic brakes, pump the brake pedal three times. Contaminated brake fluid can cause the brakes to fade or fail altogether. Determine whether the brake system indicator lamp is activated when the electrical power source to the antilock or variable proportioning unit is disconnected. (B) The average control force for the baseline check times 0.60. whichever is lower (but in no case lower than 5 pounds). With the brakes fully released at all times, drive the vehicle for 2 min at a speed of 5 mph in any combination of forward and reverse directions, through a trough having a water depth of 6 in. I'm a new noob here, but from what I've read. Conversely, if the pressure is too high, it can cause the brakes to lock up. Make 15 stops, each from 60 mph, with the backup system activated for the failed subsystem, to achieve an average deceleration of 12 fpsps for each stop. For all other tests during all decelerations, the transmission selector is in the control position, other than overdrive, recommended by the manufacturer for driving on a level surface at the applicable test speed. Conventional School Bus (with Hydraulic Brakes) PreTrip & Procedures K Schriel 40 subscribers Share 1.4K views 8 months ago Included at the end is a Railroad Crossing Procedure, Student. The CamLaster brake has 2 key design differences over traditional S-cam brakes. All vehicle openings (doors, windows, hood, trunk, convertible top, cargo doors, etc.) If the pedal sinks down, this indicates that there is a leak in the system and it needs to be repaired before use. 17 years in the truck & bus world, 10 years at an IH Dealer, ASE Certified Master Medium & Heavy Truck Technician and Advanced Level Diesel Engine Diagnostic Specialist, IH Diamond Certified 5 Times, Instructor of Apprentice Techs in Engines, Fuels, Electrical & Electronics. Move the bus forward at approximately 5 miles per hour. Except where an adjustment is specified, after each brake application accelerate to 40 mph and maintain that speed until making the next brake application at a point 1 mile from the initial point of the previous brake application. If it does, there may be a leak. The eCFR is displayed with paragraphs split and indented to follow (a) Each indicator lamp activated due to a condition specified in S5.3.1 shall remain activated as long as the malfunction exists, whenever the ignition (start) switch is in the on (run) position, whether or not the engine is running. Stopping distance means the distance traveled by a vehicle from the point of application of force to the brake control to the point at which the vehicle reaches a full stop. Linings are assumed adjusted for normal operating clearance in the released position. Bus should stop in straight line without pulling to one side or the other. is available with paragraph structure matching the official CFR (2) Except for a separate indicator lamp for an anti-lock system, a regenerative system, or an indicator for both anti-lock and regenerative system, the letters and background of each separate indicator lamp shall be of contrasting colors, one of which is red. 0000001722 00000 n AIR BRAKES 100%. The Electronic Code of Federal Regulations (eCFR) is a continuously updated online version of the CFR. HW[sF~eWJe! S7.13 Service brake system - second fade and recovery test. (g) For an EV with RBS that is part of the service brake system, failure of the RBS. 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. 0000000859 00000 n (For vehicles equipped with brake power unit or brake power assist unit.). Next, start the engine and let it idle for a few minutes to warm up the hydraulic fluid. Unless otherwise specified the brake temperature is 150 F. S5.1.1.3 In the third effectiveness test the vehicle shall be capable of stopping at lightly loaded vehicle weight from 60 mph within the corresponding distance specified in column III of table II. Apply and hold the service brakes for a minute. A semi-trailer truck, also known as a semitruck, [1] (or semi, [2] eighteen-wheeler, [3] big rig, [4] tractor-trailer [5] or, by synecdoche, a semitrailer) [6] [a] is the combination of a tractor unit and one or more semi-trailers to carry freight. Purpose. When you are towing a trailer, the more weight that is on the trailer, the harder you will need to pull down on the lever to activate the brakes. Nomenclature changes to part 571 appear at 69 FR 18803, Apr. However, at the option of the manufacturer, the following test procedure and sequence may be conducted: S7.1, S7.2, S7.3, S7.4, S7.5(b), S7.6, S7.7, S7.5(a), S7.8, S7.9, S7.10, and S7.18. 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. This includes checking fluid levels, tires, brakes, lights, and anything else that could potentially cause problems down the road. If the pressure is too low, it will not engage the brakes properly. learn more about the process here. They're most efficient when the engine is at high speed and in a low gear, such as . 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. The cast disc (rotor) is bolted to the hub assembly. Where manufacturer options are specified, the manufacturer shall select the option by the time it certifies the vehicle and may not thereafter select a different option for the vehicle. b. Air Disc Brakes are the way to go, as they become more common. Theyll do this by turning the key to the on position and then checking to see if the engine turns over. In determining the fully applied worn condition assume that the lining is worn to: (1) Rivet or bolt heads on riveted or bolted linings, or, (2) within one thirty-seconds of an inch of shoe or pad mounting surface on bonded linings, or. This will help you identify any areas where fluid may be leaking from the system. Air Brakes - They just plain Sound Bad-Ass!! This questions appears in the following tests: Colorado Double District Of Columbia Class A Knowledge Test Illinois Passenger A. Why yes, the ORIGinal CHARGER is a Fastback. (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. The first test is a pressure check. Since most large trucks have air brakes then why not large school buses. If the power assist fail on a hydraulic brake system A. you will NOT be able to stop the bus B. Then make six stops from 60 mph. 9, 2004. Use the navigation links in the gray bar above to view the table of contents that this content belongs to. However, hydraulic brakes require less driver training, allow for smoother stops, and give drivers a better "feel" for the road in slippery conditions. Then start here with FREE Practice Tests for Commercial Drivers. This members-only test covers must-know topics including medical certificate renewal, preventing brake fade, and more. S6.14 Special drive conditions. contact the publishing agency. Advanced Member, Thomas Ford 85-16 1 Depleted. They usually always have air ride suspension on the rear that auto levels to what is needed. S7.17 Spike stops. In the case of vehicles burnished in accordance with S7.4.2.1(a) of this section, reburnish the vehicle by making 35 snubs from 60 to 20 mph, but if the hottest brake temperature reaches 500 F 50 F, make the remainder of the brake applications from the highest snub condition listed in Table IV that will maintain the hottest brake temperature at 500 F 50 F.

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hydraulic brake test on school bus

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