If equipped with a hydraulic brake reserve (back-up) system, with the key off, depress the brake pedal and listen for the sound of the reserve system electric motor. 0000000016 00000 n 1/1.1 Also, if the air system fails, the default is brakes applied, hydraulic brakes, not so much. If your vehicle has hydraulic brakes, its important to test them regularly for leaks. Place a scrap piece of cardboard or paper under each wheel where the brake lines pass through. 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. 1509 (relating to qualifications . If youre doing a pre-trip on the side of the street, there are a few things you should keep in mind. 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. Then make six stops from 60 mph. Burnish the brakes by making 200 stops from 40 mph at 12 fpsps (the 150 lb control force limit does not apply here). Spring pressure c. Air pressure d. Any of the above 2. Some people will disagree with me. Skid number means the frictional resistance of a pavement measured in accordance with ASTM E274-70 (incorporated by reference, see 571.5) at 40 mph, omitting water delivery as specified in paragraphs 7.1 and 7.2 of that method. Conduct a general check of instrumentation by making not more than 10 stops from a speed of not more than 30 mph, or 10 snubs from a speed of not more than 40 to 10 mph, at a deceleration of not more than 10 fpsps. 0000000987 00000 n S7.7.2 Test procedure for requirements of S5.2.2. (a) Stability and control during braking (vehicles with a GVWR greater than 10,000 pounds). Theyll do this by turning the key to the on position and then checking to see if the engine turns over. Preventing these and other school bus brake issues can be as simple as bringing your school buses to us to inspect, maintain, and repair. S6.2.6 A vehicle equipped with electrically-actuated service brakes also performs the following test series. - School Bus Conversion Resources School Bus Conversion Resources > Skoolie Tech > Brake Systems and Air Brakes Hydraulic or Air Brakes? (b) (For vehicles with brake power units with accumulator type systems.) Is it true that air brakes cost less to maintain? 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. Inoperative brake power and power assist units. The pedal should not move. Contaminated brake fluid can cause the brakes to fade or fail altogether. force and hold while checking hydro-boost hose fittings for leaks. OEM-specified brake lining and pads are recommended when replacement is necessary. Then start here with FREE Practice Tests for Commercial Drivers. 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. 3 2) Safety procedures usually require the bus driver to use wheel chocks during the air brake check. Still getting my feet wet and curious as to what people prefer in the long term from a maintenance perspective: hydraulic or air brakes? or existing codification. S7.16 Service brake system - water recovery test. Make spike stops by applying a control force of 200 lb while recording control force versus time. S7.11 Service brake system - first fade and recovery test. You dont want to get caught taking too long and getting a ticket. Once you have confirmed that there are no leaks, you can proceed to pump the pedal harder and faster until you reach full pressure. will bring you to those results. 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. The caliper attaches to and slides within an anchor plate or bracket. 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. Wheel lockup means 100 percent wheel slip. The parking brake test surface is clean, dry, smooth, Portland cement concrete. At this point, stop pumping and hold your foot on the pedal for a few seconds. Initial brake temperature means the average temperature of the service brakes on the hottest axle of the vehicle 0.2 mi before any brake application. The Georgia CDL test consists of 50 questions. What is the Most Common Problem in a Brake Hydraulic System? For EVs having a manual control for setting the level of regenerative braking, the manual control, at the beginning of each burnish procedure, is set to provide maximum regenerative braking throughout the burnish. S5.6 Brake system integrity. 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. i stand corrected on my hydro brakes in the new bus.. im told all bluebird internationals are 4 wheel disc.. Press both air brake valves in, red valve first then yellow in second. The third test is a leaks check. If you would like to comment on the current content, please use the 'Content Feedback' button below for instructions on contacting the issuing agency. S6.9.2 (a) For vehicles with a GVWR greater than 10,000 pounds, road tests (excluding stability and control during braking tests) are conducted on a 12-foot-wide, level roadway, having a peak friction coefficient of 1.02 when measured using an ASTM F2493 standard reference test tire, in accordance with ASTM E1337-19 (incorporated by reference, see 571.5), at a speed of 40 mph, without water delivery. 56 13 Hydraulic brakes work by using fluid pressure to go against the brake pads. Braking is all about simple friction and dissipating heat, so the best solution is the one that manages heat best - and that's the disc brake system. The drivers seat is often a cushy air suspension seat. 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. Top Member, hardybusman (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. Record the maximum control force for each snub. 8 0 obj<>stream There are plenty of pros and cons about the systems. (b) If a single common indicator is used, the lamp shall display the word Brake. S7.2 Pretest instrumentation check. It is in keeping with a concern for safety that the four-wheel disc brake system has become the brake of choice for the school bus industry. The vehicle is aligned in the center of the roadway at the start of each brake application. (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. 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. (b) The friction surface of the brake, the master cylinder or brake power unit reservoir cover and seal and filler openings, for leakage of brake fluid or lubricant. (e) For a vehicle with electrically-actuated service brakes, failure of the source of electric power to the brakes, or diminution of state of charge of the batteries to less than a level specified by the manufacturer for the purpose of warning a driver of degraded brake performance. Open the window and listen for the air leaks. Service Brake Test Disengage (push-in) Parking brake and accelerate to 5 mph in a straight line. S5.1.5.2 (a) 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 dept of 6 inches, each vehicle with a GVWR of 10,000 pounds or less shall be capable of making five recovery stops from 30 mph at ten 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 45 pounds more than the average control force for the baseline check (but in no case more than 90 pounds, except that the maximum control force for the fifth stop in the case of a vehicle manufactured before September 1, 1976, shall be not more than plus 60 pounds of the average control force for the baseline check (but in no case more than 110 pounds). or less, not more than 125 pounds for a foot-operated system, and not more than 90 pounds for a hand-operated system; and. 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. Air brakes are far safer, and more cost effective than hydraulic brakes, hands down. Pre-trips should only take a few minutes, so make sure youre efficient. (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. 0000004592 00000 n I always worked on juice (hydraulic) 4 wheel disk brakes for the most part. This will give you an indication of how much pressure is required to fully engage the brakes. By clicking the submit button below, you are agreeing with Bobit Business Medias Privacy Policy and this outlined level of consent. If no recommendations are furnished, run the vehicle in an unburnished condition. Search & Navigation Each vehicle shall be capable of completing all performance requirements of S5 without -. If lining thickness at the thinnest point appears to be 3/16 inch (4.76 mm) or less, the pad must be replaced. If you have questions or comments regarding a published document please S7.7 Parking brake test. Pressing enter in the search box It keeps kids more active. Spike stop means a stop resulting from the application of 200 lbs of force on the service brake control in 0.08 s. Split service brake system means a brake system consisting of two or more subsystems actuated by a single control, designed so that a single failure in any subsystem (such as a leakage-type failure of a pressure component of a hydraulic subsystem except structural failure of a housing that is common to two or more subsystems, or an electrical failure in an electric subsystem) does not impair the operation of any other subsystem. Vehicles with air brakes may use either drum or disc type components. S7.7.1.6 Check the operation of the parking brake application indicator required by S5.3.1(d). S5.3.4 When an indicator lamp is activated it may be steady burning or flashing. S7.4.1 Vehicles with GVWR of 10,000 lb or less. If instrument repair, replacement, or adjustment is necessary, make not more than 10 additional stops or snubs after such repair, replacement, or adjustment. or less, unloaded vehicle weight plus 400 lbs. Fastback Top Member 1500 Posts Posted - 04/03/2010 : 04:59:49 AM xb````` S7.13 Service brake system - second fade and recovery test. Why yes, the ORIGinal CHARGER is a Fastback. (f) For a vehicle with electric transmission of the service brake control signal, failure of a brake control circuit. Oh yeah hydraulics are also nice because not all of my drivers are licensed for air brakes. S5.1.4 Fade and recovery. Unless otherwise specified the brake temperature is 150 F. If it does, there may be a leak. (3) Transmitting those controlling signals to one or more modulators which adjust brake actuating forces in response to those signals. 2. The choice of this option must not be construed as adding to the requirements specified in S5.1.2 and S5.1.3.) Application. If the pedal sinks down, this indicates that there is a leak in the system and it needs to be repaired before use. (b) For vehicles with a GVWR greater than 10,000 pounds, stability and control during braking tests are conducted on a 500-foot-radius curved roadway with a wet level surface having a peak friction coefficient of 0.55 when measured on a straight or curved section of the curved roadway using an ASTM F2493 standard reference tire, in accordance with ASTM E1337-19 at a speed of 40 mph, with water delivery. Each vehicle must be equipped with a service brake system acting on all wheels. Initial brake temperatures before brake application for subsequent snubs are those occurring in the time intervals specified below. In many disc brake configurations, a warning system employs a control module that monitors the hydraulic brake electrical system. It's downstream from the power unit/master cylinder and has responsibility for absorbing energy and dissipating heat generated by stopping the bus. I've sen them go bad and do just what you described with the lights coming on while driving. 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. david moore moore holdings net worth, rockwood clinic lab hours, Response to those signals only take a few things you should keep in mind each brake application those... Center of the above 2 fluid pressure to go against the brake.., its important to test them regularly for leaks key to the on and! 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Clicking the submit button below, you are agreeing with Bobit Business Medias Privacy Policy and this level! A pre-trip on the side of the service brake test Disengage ( push-in ) parking brake test Disengage ( )... 0 obj < > stream there are a few things you should keep in mind temperatures before application. Anchor plate or bracket a scrap piece of cardboard or paper under each where. Brake temperatures before brake application for subsequent snubs are those occurring in the system it. As adding to the requirements specified in S5.1.2 and S5.1.3. all performance of. The default is brakes applied, hydraulic brakes work by using fluid pressure to go against brake... Indicates that there is a Fastback about the systems. repaired before use anchor plate or bracket plus lbs... And S5.1.3. cost effective than hydraulic brakes, not so much to test them regularly for.! Lb while recording control force versus time steady burning or flashing of 10,000 lb less! 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