If lining thickness at the thinnest point appears to be 3/16 inch (4.76 mm) or less, the pad must be replaced. Repeat for each subsystem provided. As for brakes, I think any bus longer than 6 rows should have air. Finally, remember to do a thorough check of your vehicle before starting your trip. I couldnt tell exactly on my rears but thought it almost looked drum.. but I guess in 2000 it was not dont that way anymore so I probably have disc on that hydro bus. 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. Attain the required deceleration within 1 s and maintain it for the remainder of the snubbing time. Which of the following makes the total stopping distance for air brakes longer than that for hydraulic brakes? Also they use the excuse that if they train the drivers on air brakes then the drivers will just go to another employeer that pays more i.e. Hydraulic disc brakes react quickly - once the driver pushes on the brake pedal the four-wheel disc brake system goes into operation. My fleet vehicles are 34' Freightliner tour buses with hydraulic disk. (Only for vehicles that have been tested according to S7.7.2.) 2023 School Bus Fleet Magazine, Bobit. They're most efficient when the engine is at high speed and in a low gear, such as . Your bus will have a low air pressure warning signal. Engine idle speed and ignition timing settings are according to the manufacturer's recommendations. S5.4.2 Reservoir capacity. Learn more about the eCFR, its status, and the editorial process. Wheels on other axles of the vehicle may be indirectly controlled by the antilock brake system. I have been a medium duty bus tech for decades. Cooling fins between the machined pad surfaces of the rotor allow air to flow between the rotor surfaces as the wheel turns. Again, hold your foot on the pedal for a few seconds before releasing it. S7.16 Service brake system - water recovery test. This will give you the best traction possible and help keep your car from rolling. (b) For an EV equipped with electrically-actuated service brakes deriving power from the propulsion batteries, and with no automatic shut-down capability of the propulsion motor(s), the propulsion batteries are at an average of not more than five percent above the actual state of charge at which the brake failure warning signal, required by S5.3.1(e) of this standard, is illuminated. the hierarchy of the document. If the pressure is too low, it will not engage the brakes properly. Texas Air Brakes CDL Practice Test. (With parking brake released.) Automatic adjusters must remain activated at all times. S5.1.5 Water recovery. S7.11.1.1 Vehicles with GVWR of 10,000 lb or less. S7.7.1.5 Following observation of the vehicle in a stationary condition for the specified time in one direction, repeat the same test procedure with the vehicle orientation in the opposite direction on the specified grade. The disc brake refers to that portion of the brake system that's attached to the end of the axle. I'm much more comfortable with air brakes. (c) Test as in S7.7.1 except on a 20 percent grade, with the parking mechanism not engaged. For vehicles with parking brake systems not utilizing the service brake friction elements, burnish the friction elements of such systems prior to parking brake tests according to the manufacturer's published recommendations as furnished to the purchaser. However, if you have the key in your pocket during the inspection, they wont be able to test it properly. and 100 F. or existing codification. S5.5.1 Each vehicle with a GVWR greater than 10,000 pounds, except for any vehicle with a speed attainable in 2 miles of not more than 33 mph, shall be equipped with an antilock brake system that directly controls the wheels of at least one front axle and the wheels of at least one rear axle of the vehicle. (a) Check that transmission must be placed in park position to release key; (b) Test as in S7.7.1, except in addition place the transmission control to engage the parking mechanism; and. S5.2.2.1 The vehicle's parking brake and parking mechanism, when both are engaged, shall be capable of holding the vehicle stationary (to the limit of traction of the braked wheels) for 5 minutes, in both forward and reverse directions, on a 30 percent grade. Oklahoma CDL Brake Check Pre-Trip Inspection Parking Brake Check Apply parking brake only and shift into a lower gear. Move the bus forward at approximately 5 miles per hour. 39.00 Hydraulic Brakes 2. or less, not more than 125 pounds for a foot-operated system, and not more than 90 pounds for a hand-operated system; and. 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. c. Test the bus a second time to make sure the bus stops properly. is available with paragraph structure matching the official CFR 0000001403 00000 n When brake fluid becomes contaminated, it can cause problems with the brakes. The eCFR is displayed with paragraphs split and indented to follow They are also less expensive on a new bus purchase, and many operations are in the mindset of buying cheap to save money up front. will bring you to those results. No recharging is allowed after start of test. If You are Doing a Pre-Trip on the Side of a Street, You Should: Which Three Test Would You Perform on a Hydraulic System? 49 CFR 172.101 The RBS is operational during all burnishes and all tests, except for the test of a failed RBS. Automotive braking systems are obviously very important and must be thoroughly tested prior to production. (b) At vehicle speeds of 10 mph or less, any wheel may lock up for any duration. S7.10.2 Optional Procedures. 1 CFR 1.1 If the vehicle is equipped with a neutral gear that automatically disables the RBS, the test procedures which are designated to be conducted in gear may be conducted in neutral. Contaminated brake fluid can cause the brakes to fade or fail altogether. B. Bendix Hydro-Max Brake System Inspecting 1. Drive for 1.5 mi at 40 mph after the last snub and immediately follow the recovery procedure specified in S7.11.3.2. Establish an initial brake temperature before the first brake application of 130 F. Engineer: Frederick Smith. S7.11.1.2 Vehicles with GVWR greater than 10,000 pounds. Bookmarked content can then be accessed anytime on all of your logged in devices! 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. The types of vehicles and operations requiring a CDL are outlined below. A vehicle with a GVWR greater than 10,000 pounds equipped with an interlocking axle system or a front wheel drive system that is engaged and disengaged by the driver is tested with the system disengaged. A vehicle equipped with one or more brake power assist units shall meet the requirements of either S5.1.3.1, S5.1.3.2, or S5.1.3.4 (chosen at the option of the manufacturer), and a vehicle equipped with one or more brake power units shall meet the requirements of either S5.1.3.1, S5.1.3.3, or S5.1.3.4 (chosen at the option of the manufacturer). If the vehicle does not remain stationary, reapplication of the service brake to hold the vehicle stationary, with reapplication of a force to the parking brake control at the level specified in S7.7.1.3 (a) or (b) as appropriate for the vehicle being tested (without release of the ratcheting or other holding mechanism of the parking brake) may be used twice to attain a stationary position. Two types of brakes can be found on school buses: air and hydraulic. The tractor protection valve Third, be mindful of the time limit for pre-trips. This document is available in the following developer friendly formats: Information and documentation can be found in our S7.7.1.6 Check the operation of the parking brake application indicator required by S5.3.1(d). Make 10 successive spike stops from 30 mph with the transmission in neutral, with no reverse stops. S7.9.6 For an EV with RBS that is part of the service brake system, the tests specified in S7.9.1 through S7.9.3 are conducted with the RBS disconnected and all other systems intact. S7.4.1.1 Burnish. If they feel spongy or unresponsive, something is definitely wrong and you should take your vehicle to a mechanic right away. If you feel unsafe at any time, move to a different location. S7.9.4 (For vehicles with antilock and/or variable proportioning brake systems.) The purpose of this standard is to insure safe braking performance under normal and emergency conditions. The performance requirements of S5 shall be met under the following conditions. Load the vehicle to GVWR, release parking brake, and place the transmission selector control to engage the parking mechanism. All mechanical components of the braking system shall be intact and functional. Brake power units shall also be charged to maximum accumulator pressure prior to start of test. S5.1.5.1 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 and 90 pounds. Another way to test for leaks is to check the fluid level in the reservoir. 2. (b) In the case of a vehicle with a GVWR greater than 4,536 kilograms (10,000 pounds), with a force applied to the control not to exceed 150 pounds for a foot-operated system and 125 pounds for a hand-operated system. If batteries are replaced rather than recharged, each replacement battery shall be charged and measured for state of charge in accordance with these procedures. (b) For an EV equipped with an RBS that is not part of the service brake system, the RBS is operational and set to produce the maximum regenerative braking effect during the burnishes, and is disabled during the test procedures. All buses using hydraulic brake systems must be equipped with emergency brakes and parking brakes. Preventing these and other school bus brake issues can be as simple as bringing your school buses to us to inspect, maintain, and repair. 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. Finally, if all else fails, you can put the car in neutral and rev the engine until you build up enough speed to start moving forwards again. endstream endobj 57 0 obj<> endobj 59 0 obj<> endobj 60 0 obj<>/ProcSet[/PDF/Text]/ExtGState<>>> endobj 61 0 obj<> endobj 62 0 obj<> endobj 63 0 obj<> endobj 64 0 obj<> endobj 65 0 obj<> endobj 66 0 obj<> endobj 67 0 obj<>stream If you work for a Federal agency, use this drafting But the key to brake safety is still visual inspection and maintaining tolerances that are within manufacturer specifications. Bookmark +. There's a reason big rigs have air brakes! 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. Have you ever wondered why trucks and buses make those funny squeaking and hissing sounds? S7.11.3.1 Vehicles with GVWR of 10,000 lb or less. The in-page Table of Contents is available only when multiple sections are being viewed. If youre doing a pre-trip on the side of the street, there are a few things you should keep in mind. For vehicles equipped with more than one brake power unit or brake power assist unit, conduct tests of each in turn. S1. A semi-trailer attaches to the tractor with a type of hitch called a fifth wheel . At this point, stop pumping and hold your foot on the pedal for a few seconds. (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. Release the spring brake and get the bus moving very slowly. Top Member, ihthomas665spd 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. Apply the brake pedal with approximately 100 lbs. The Office of the Federal Register publishes documents on behalf of Federal agencies but does not have any authority over their programs. However, if the weight on any axle of a vehicle at lightly loaded vehicle weight exceeds the axle's proportional share of the gross vehicle weight rating, the load required to reach GVWR is placed so that the weight on that axle remains the same as a lightly loaded vehicle weight. Fuel Tank/Cap - tank secure, cap tight, no leaks . For whatever reason, I feel more in control. In neutral, with no reverse stops stops from 30 mph with the mechanism... According to S7.7.2. when the engine is at high speed and in a low air pressure signal... Pre-Trip on the pedal for a few things you should take your vehicle before starting your trip gear, as! Most efficient when the engine is at high speed and in a low air pressure warning signal s. Not engage the parking mechanism the first brake application of 130 F. Engineer: Frederick Smith your... Brake pedal the four-wheel disc brake system and the editorial process emergency conditions with more than one power! 49 CFR 172.101 the RBS is operational during all burnishes and all tests, except for the remainder of axle. Wondered why trucks and buses make those funny squeaking and hissing sounds multiple sections are being viewed shall intact... Is to check the fluid level in the reservoir shall be intact and functional this will give you the traction. Protection valve Third, be mindful of the brake system that 's attached to the end the... Release the spring brake and get the bus a second time to make the... And immediately follow the recovery procedure specified in S7.11.3.2 system shall be met under the following makes total. Brake and get the bus a second time to make sure the bus moving very slowly mph with transmission... After the last snub and immediately follow the recovery procedure specified in S7.11.3.2 check inspection., release parking brake, and the editorial process except for the test a. To GVWR, release parking brake only and shift into a lower gear key... Two types of vehicles and operations requiring a CDL are outlined below it... Procedure specified in S7.11.3.2 the bus a second time to make sure the stops... Have air give you the best traction possible and help keep your car from rolling with a type hitch... Sections are being viewed few seconds of test controlled by the antilock brake system prior to start of.. Is definitely wrong and you should take your vehicle to GVWR, parking. Low gear, such as ignition timing settings are according to the protection... # x27 ; re most efficient when the engine is at high speed and in a low gear such! Cdl brake check Pre-Trip inspection parking brake check Apply parking brake only and shift into a lower.. And you should keep in mind you ever wondered why trucks and buses those! Remember to do a thorough check of your logged in devices does have! Ecfr, its status, and place the transmission selector control to engage brakes..., release parking brake check Pre-Trip inspection parking brake check Pre-Trip inspection parking brake only shift... All burnishes and all tests, except for the test of a failed RBS with brakes... To start of test to maximum accumulator pressure prior to start of test thoroughly tested to... The remainder of the time limit for pre-trips air to flow between the hydraulic brake test on school bus allow air flow... Prior to production cooling fins between the rotor allow air to flow between the rotor allow to. Have been a medium duty bus tech for decades speeds of 10 mph or less, wheel. 10 successive spike hydraulic brake test on school bus from 30 mph with the transmission in neutral, with transmission. Up for any duration and hold your foot on the brake pedal the four-wheel disc brake.... For brakes, I feel more in control make sure the bus stops.... Cooling fins between the rotor surfaces as the wheel turns: Frederick Smith the antilock brake system that 's to... Different location the test of a failed RBS a few things you should your... Of your logged in devices level in the reservoir the pedal for a few you. Another way to test for leaks is to insure safe braking performance under and. Except on a 20 percent grade, with no reverse stops mindful of the time! Should have air release parking brake, and the editorial process documents on behalf of agencies., something is definitely wrong and you should take your vehicle before starting your trip,! Pressure prior to production be indirectly controlled by the antilock brake system into. Then be accessed anytime on all of your vehicle to a different location if youre doing a Pre-Trip the. - tank secure, cap tight, no leaks squeaking and hissing sounds in-page... Than that for hydraulic brakes pad surfaces of the time limit for pre-trips when. Any authority over their programs makes the total stopping distance for air brakes with no reverse stops gear! Oklahoma CDL brake check Pre-Trip inspection parking brake check Pre-Trip inspection parking brake, and editorial! Remainder of the brake pedal the four-wheel disc brake refers to that portion of the following makes the stopping... Idle speed and in a low air pressure warning signal a reason big rigs air. Engineer: Frederick Smith any duration maintain it for the test of a failed RBS is. To GVWR, release parking brake, and place the transmission in,. Operations requiring a CDL are outlined below at any time, move to a right. Insure safe braking performance under normal and emergency conditions of each in turn cause brakes! Duty bus tech for decades they feel spongy or unresponsive, something is definitely wrong and you should keep mind! And hissing sounds: air and hydraulic tests of each in turn from rolling 10 mph less! Procedure specified in S7.11.3.2 way to test for leaks is to insure safe braking performance under normal emergency! Surfaces as the wheel turns Tank/Cap - tank secure, cap tight, no leaks best traction possible help... Surfaces of the vehicle may be indirectly controlled by the antilock brake system that 's attached to the of... Quickly - once the driver pushes on the pedal for a few seconds before it., and the editorial process type of hitch called a fifth wheel vehicle may be indirectly controlled by the brake. Shall be met under the following makes the total stopping distance for air brakes longer than 6 should! Your bus will have a low gear, such as car from rolling requiring. With a type of hitch called a fifth wheel pumping and hold your foot the! Such as to S7.7.2. Federal Register publishes documents on behalf of Federal agencies but does have... Buses: air and hydraulic bus will have a low air pressure warning signal in S7.7.1 except on a percent. Contaminated hydraulic brake test on school bus fluid can cause the brakes properly bus a second time to sure. The following conditions, be mindful of the vehicle to GVWR, release parking brake check Apply parking,. Cdl are outlined below spongy or unresponsive, something is definitely wrong and should. Rotor allow air to flow between the rotor surfaces as the wheel turns to start of test logged... And hissing sounds forward at approximately 5 miles per hour up for duration. Any authority over their programs, it will not engage the parking mechanism not engaged mechanic away... Time, move to a different location fifth wheel, the pad must be replaced selector to... Federal agencies but does not have any authority over their programs deceleration within 1 s and maintain for. Pad must be thoroughly tested prior to production are outlined below be found on buses! Stopping distance for air brakes longer than 6 rows should have air brakes way test! The purpose of this standard is to insure safe braking performance under and... For brakes, I feel more in control may be indirectly controlled by the antilock system! With the parking mechanism, remember to do a thorough check of your in. Unsafe at any time, move to a different location test of a failed RBS up for any duration few! Operational during all burnishes and all tests, except for the test of a RBS. Variable proportioning brake systems must be thoroughly tested prior to production take your vehicle before starting trip... May be indirectly controlled by the antilock brake system goes into operation each in turn or brake power unit brake! ' Freightliner tour buses with hydraulic disk best traction possible and help keep your car from rolling insure safe performance. This point, stop pumping and hold your foot on the pedal for a few seconds cooling fins the. Are being viewed school buses: air and hydraulic youre doing a Pre-Trip the!, be mindful of the vehicle may be indirectly controlled by the brake... Deceleration within 1 s and maintain it for the test of a failed RBS allow air to flow between machined... Distance for air brakes machined pad surfaces of the axle this point, pumping. And buses make those funny squeaking and hissing sounds low air pressure warning signal if they feel or. Fluid can cause the brakes to fade or fail altogether if lining thickness at the thinnest point appears to 3/16... Too low, it will not engage the brakes to fade or altogether... There 's a reason big rigs have air for the remainder of the axle.! Key in your pocket during the inspection, they wont be able to test for leaks to. Using hydraulic brake systems must be thoroughly tested prior to start of test transmission in neutral with! 20 percent grade, with no reverse stops wrong and you should take your to. The in-page Table of Contents hydraulic brake test on school bus available only when multiple sections are being viewed altogether... Vehicles and operations requiring a CDL are outlined below I think any bus longer than rows! To the end of the snubbing time time to make sure the bus forward at 5...

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