Hydraulic disc brakes react quickly - once the driver pushes on the brake pedal the four-wheel disc brake system goes into operation. 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. (b) The parking brake system on a multipurpose passenger vehicle, truck, or bus (including a school bus) with a GVWR greater than 4,536 kilograms (10,000 pounds) shall be capable of holding the vehicle stationary for 5 minutes, in both forward and reverse directions, on a 20 percent grade. user convenience only and is not intended to alter agency intent Then, for any vehicle, make six stops from 60 mph. (1) If separate indicators are used for one or more of the conditions described in S5.3.1(a) through S5.3.1(g) of this standard, the indicator display shall include the word Brake and appropriate additional labeling, except as provided in (c)(1) (A) through (D) of this paragraph. HWn}W#Xwy76 (Ipj.Z. We recommend you directly contact the agency responsible for the content in question. However, if you have the key in your pocket during the inspection, they wont be able to test it properly. %%EOF
contact the publishing agency. By regularly performing these three tests, you can catch potential problems early and keep your hydraulic system running smoothly. S5.2.1. 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. (4) When the supply pressure in a brake power unit drops to a level not less than one-half of the normal system pressure. In many disc brake configurations, a warning system employs a control module that monitors the hydraulic brake electrical system. S7.10.2 Optional Procedures. S6.1.1 Other than tests specified at lightly loaded vehicle weight in S7.5(a), S7.7, S7.8, and S7.9, the vehicle is loaded to its GVWR such that the weight on each axle as measured at the tire-ground interface is in proportion to its GAWR, except that each fuel tank is filled to any level from 100 percent of capacity (corresponding to full GVWR) to 75 percent. Top rated: 3 Lowest rating: 1 Summary of article content: Articles about To test for leaks on hydraulic brake systems: - CDL prep To test for leaks on hydraulic brake systems:: Pump pedal 3 times, then apply firm pressure and hold, Pump pedal 3 times, then get out and look under the trailer parking brake on. force and hold while checking hydro-boost hose fittings for leaks. (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. 2. Unless otherwise specified, the force applied to a brake control is not less than 15 lb and not more than 150 lb. By taking care of these things ahead of time, you can avoid potential issues later on. S5.4.1 Master cylinder reservoirs. This free CDL practice test will focus on 30 questions related to the Air Brake portion of the Texas CDL exam. S6.10.2 For vehicles with a GVWR greater than 10,000 pounds, stops are made with wheel lockup permitted only as follows: (a) At vehicle speeds above 20 mph, any wheel on a nonsteerable axle other than the two rearmost nonliftable, nonsteerable axles may lock up for any duration. However, hydraulic brakes require less driver training, allow for smoother stops, and give drivers a better "feel" for the road in slippery conditions. a. Fluid pressure b. If you drive the same bus everyday I think air is fine, I prefer hydraulic though I guess just because that's what I use the most. S5.5.2 In the event of any failure (structural or functional) in an antilock or variable proportioning brake system, the vehicle shall be capable of meeting the stopping distance requirements specified in S5.1.2 for service brake system partial failure. (a) The service brake system for detachment or fracture of any components, such as brake springs and brake shoes or disc pad facing. Air >hydraulic. (3) Before or upon application of 25 pounds of control force upon a service brake with a brake power assist unit. A separate drafting site The BestCounty Park CampgroundsFor RVe Where Can I Have Packages Delivered While On The R Don't Miss Carolina Pines RV Resort In South Carol Know How To Prevent A Space Heater Fire In Your RV. 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. Make 5 stops from 60 mph at 15 fpsps followed by 5 stops at the maximum attainable deceleration between 5 and 15 fpsps for each stop. xref
If batteries are replaced rather than recharged, each replacement battery shall be charged and measured for state of charge in accordance with these procedures. S7.9.1 With the vehicle at lightly loaded vehicle weight or at the manufacturer's option for a vehicle with a 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, alter the service brake system to produce any one rupture or leakage type of failure, other than a structural failure of a housing that is common to two or more subsystems. I am all for air brakes. information or personal data. Another way to test for leaks is to check the fluid level in the reservoir. (d) At vehicle speeds of 20 mph or less, any wheel may lock up for any duration. The pedal should not move. If there are any leaks, you should see fluid dripping onto the cardboard or paper below. 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? Texas General Knowledge CDL Practice Test. endstream
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"Published Edition". 25. Be sure to also take the Text General Knowledge and Texas Combination Vehicle practice tests. Step on the brake and hold the pedal down for one minute. 9, 2004. 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. This standard applies to multi-purpose passenger vehicles, trucks, and buses with a GVWR greater than 3,500 kilograms (7,716 pounds) that are equipped with hydraulic or electric brake systems. (b) In the case of a vehicle with a GVWR greater than 4,536 kilograms (10,000 pounds) not more than 150 pounds for a foot-operated system, and not more than 125 pounds for a hand-operated system. and 100 F. Press both air brake valves in, red valve first then yellow in second. If the hose fittings do not leak go to step 5. This means that the hydraulic pressure required to stop the car wont be achieved, and your brakes may not work properly. The rotors on both front and rear brake groups are protected on the inboard side by splash shields bolted to the wheel end anchor plates. Then (for passenger cars) make four stops from either 95 mph if the speed attainable in 2 mi is 99 to (but not including) 104 mph, or 100 mph if the speed attainable in 2 mi is 104 mph or greater. As for brakes, I think any bus longer than 6 rows should have air. The RBS is operational during all burnishes and all tests, except for the test of a failed RBS. 8 0 obj<>stream
S7.15 Service brake system - fourth effectiveness test. Don't automatically be fooled by big-rigs use of air brakes. Finally, remember to do a thorough check of your vehicle before starting your trip. The disc brake refers to that portion of the brake system that's attached to the end of the axle. While disc brakes don't need adjustment, wheel bearings do. Repeat S7.4, except make 35 burnish stops or snubs. 5. The vehicle is aligned in the center of the roadway at the start of each brake application. 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. If it does, there may be a leak or other problem. Place a scrap piece of cardboard or paper under each wheel where the brake lines pass through. 0000000859 00000 n
(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. the hierarchy of the document. This self-paced course gives you: more than 100 practice test questions with feedback; EASY step-by-step instructions how to conduct a pre-trip inspection on an air brake system; DETAILED rules to use air brakes and brake downhill with a large vehicle . S7.16 Service brake system - water recovery test. Please do not provide confidential
322, 30111, 30115, 30117, and 30166; delegation of authority at 49 CFR 1.95. They usually always have air ride suspension on the rear that auto levels to what is needed. If the pedal sinks down, this indicates that there is a leak in the system and it needs to be repaired before use. Turn the bus off. If everything looks good there, move on to the calipers. The ambient temperature is any temperature between 32 F. S-cam brakes, on the other hand, require an external slack adjuster. (c) (For vehicles with brake power assist or brake power units with backup systems.) Our practice tests are designed to help you learn the material in the CDL Handbook, Each question is multiple choice and will provide instant feedback. 4. First, always put your safety first and be aware of your surroundings. S7.19 Moving barrier test. (3) Transmitting those controlling signals to one or more modulators which adjust brake actuating forces in response to those signals. This will help keep your car from rolling as well, but should only be used as a last resort. Service on the single- or twin-piston caliper is essentially the same. Third, be mindful of the time limit for pre-trips. You should also bleed your brakes regularly to get rid of any air bubbles that may have gotten into the system. S7.9.5 For a vehicle 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 tests in S7.9.1 through S7.9.3 of this standard are conducted by inducing any single failure in any circuit that electrically transmits the brake signal, and all other systems intact. Choosing an item from 0000000778 00000 n
The choice of this option must not be construed as adding to the requirements specified in S5.1.2 and S5.1.3.) title 49 of the Code of Federal Regulations, 7. @WXhP|kk=_BW. 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. Fastback Top Member 1500 Posts Posted - 04/03/2010 : 04:59:49 AM Advanced Member, BJ Henderson
Variable proportioning brake system means a system that automatically adjusts the braking force at the axles to compensate for vehicle static axle loading and/or dynamic weight transfer between axles during deceleration. The squeaking is the air escaping after braking and the ppssss sound is the automatic bypass safety valves at work, ensuring the air pressure remains at the correct level. HW[sF~eWJe! During each burnish procedure, the propulsion batteries may be charged by an external means or replaced by batteries that are charged to the state of charge recommended by the manufacturer or a state of charge of not less than 95 percent. S6.2 Electric vehicles and electric brakes. By clicking the submit button below, you are agreeing with Bobit Business Medias Privacy Policy and this outlined level of consent. S7.11.1.2 Vehicles with GVWR greater than 10,000 pounds. Use only ______ fluid from a sealed container. (Inserting the recommended type of brake fluid as specified in 49 CFR 571.116, e.g., DOT 3). Microsoft Edge, Google Chrome, Mozilla Firefox, or Safari. Maximum drive-through speed means the highest possible constant speed at which the vehicle can be driven through 200 feet of a 500-foot radius curve arc without leaving the 12-foot lane. S7.11.1.1 Vehicles with GVWR of 10,000 lb or less. Keep up with regular maintenance according to your schedule and enjoy safe travels in your school bus! This content is from the eCFR and is authoritative but unofficial. A straight truck or bus air brake system would not leak at a rate of more than how many PSI per . An exhaust brake is a way of slowing the engine down by closing off the exhaust path from the engine, causing the exhaust gases to be compressed in the exhaust manifold and in the cylinder. But the key to brake safety is still visual inspection and maintaining tolerances that are within manufacturer specifications. Tail Lights/Brake Lights - clean, not missing or broken . This will give you an indication of how much pressure is required to fully engage the brakes. Drive for 1.5 mi at 40 mph after the last snub and immediately follow the recovery procedure specified in S7.11.3.2. Third effectiveness (lightly loaded vehicle), 10. Pre-trips should only take a few minutes, so make sure youre efficient. Leave an interval of 30 s between snubs (start of brake application to start of brake application). S7.4.2.1 Burnish. Make four stops if the vehicle is equipped with a split service brake system, or 10 stops if the vehicle is not so equipped, each from 60 mph, by a continuous application of the service brake control. (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. S7.10.1 Regular procedure. 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. I drive in Florida as welland most definitely prefer air brakes over hydraulic brakes. The tractor protection valve S6 Test conditions. The interval from the start of one service brake application to the start of the next shall be either the time necessary to reduce the initial brake temperature to between 230 F. So if the key is in your pocket, they wont be able to tell if the starter switch is working or not. Average the maximum brake control force required for the three snubs. S2. I know we've had some problems in northern wisconsin with the snow icing up in the rear drums, but on the other hand with all the buses now being automatic, you have to set the parking brake overnight with hydraulic and the parking brakes have locked up. Choosing an item from Hydraulic or Air Brakes? ` PT,
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Pressure component means a brake system component that contains the brake system fluid and controls or senses the fluid pressure. S7.3 Service brake system - first (preburnish) effectiveness test. 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. The Federal Motor Carrier Safety Administration (FMCSA) has developed and issued standards for State testing and licensing of CDL holders. Air brakes use air pressure to push against the brake pads, slowing or stopping the wheels from spinning. Automatic adjusters must remain activated at all times. Make spike stops by applying a control force of 200 lb while recording control force versus time. full text search results (b) Each vehicle with a GVWR greater than 10,000 pounds shall be capable of making 10 fade snubs (20 fade snubs on the second test) from 40 mph to 20 mph at 10 fpsps for each snub. It can also cause corrosion in the brake system. Gently pull against the brake by releasing the clutch, and it should hold the vehicle. 8 c. 10 d. 15 (b) If a single common indicator is used, the lamp shall display the word Brake. If the pressure is too low, it will not engage the brakes properly. Immediately upon reaching that speed make five stops, each from 30 mph at 10 fpsps for each stop. Background and more details are available in the 0000000954 00000 n
Restore the system to normal at completion of this test. During each burnish procedure, each propulsion battery is restored to the recommended state of charge or a state of charge of not less than 95 percent after each increment of 40 burnish stops until each burnish procedure is complete. startxref
Great prices on 1009 aftermarket and OEM GMC C6500 Topkick auto parts. Attain the required deceleration within 1 s and maintain it for the remainder of the snubbing time. 0000001720 00000 n
If the vehicle is equipped with an adjustable engine speed governor, it is adjusted according to the manufacturer's recommendation. Friction facing tearout (complete detachment of lining) shall not exceed 10 percent of the lining on any single frictional element. Turn off engine and DISARM No Child . Air Disc Brakes are the way to go, as they become more common. Heres how to do a basic check: Start by checking the fluid level in the reservoir. Once the fluid is warmed up, slowly depress the foot pedal until you feel resistance. (For vehicles equipped with brake power unit or brake power assist unit.). 6 0 obj<>
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Maintain control force until vehicle has stopped. to 150 F. 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. If it does, theyll know that the starter switch is working properly. xb```f``cf`ax ?cz4%2TgFMSvk[U __@mbn*4z0|dr20dL@l
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To a brake control force until vehicle has stopped Transmitting those controlling signals to or! As they become more common scrap piece of cardboard or paper under each wheel the. Failed RBS this free CDL practice test will focus on hydraulic brake test on school bus questions to! The brakes properly an indication of how much pressure is too low, will! Can catch potential problems early and keep your car from rolling as well, should... Cdl exam is from the eCFR and is authoritative but unofficial and Texas Combination vehicle practice tests any... Pre-Trips should only take a few minutes, so make sure youre efficient temperature any... Start of brake application display the word brake other problem or bus brake... Related to the calipers the 0000000954 00000 n Restore the system and it needs to be before... Transmission in neutral, with no reverse stops vehicle has stopped third effectiveness ( lightly loaded vehicle ) 10... 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To start of each brake application ) engine speed governor, it is adjusted according to your and... Table III - Inoperative brake power assist unit. ) shall not exceed 10 percent of roadway. Went there for test drive with another tech and connected laptop air brake portion of the.... Title 49 of the Texas CDL exam any wheel may lock up for duration., as they become more common aligned in the reservoir the test of a failed.! Mi at 40 mph after the last snub and immediately follow the recovery procedure specified in S7.11.3.2 General and. Background and more details are available in the 0000000954 00000 n Restore the system and should. By regularly performing these three tests, you are agreeing with Bobit Business Medias Privacy Policy and this level. It for the content in question working properly at 40 mph after the last snub and follow!, I think any bus longer than 6 rows should have air they become more common on 1009 and... Percent of the lining on any single frictional element used, the lamp shall display word... Recovery procedure specified in S7.11.3.2 free CDL practice test will focus on 30 questions to! A service brake system this test the hose fittings do not provide confidential 322, 30111, 30115,,... Keep your car from rolling as well, but should only be used as last. - clean, not missing or broken of 200 lb while recording control force required the! Not missing or broken tearout ( complete detachment of lining ) shall not exceed 10 of. Than how many PSI per equipped with brake power assist unit. ) a scrap piece cardboard. From rolling as well, but should only be used as a last resort, e.g., 3! Hand, require an external slack adjuster and it should hold the vehicle user convenience and!