Burnish stops are conducted on any surface. Use only heavy-duty brake fluid, DOT 3. startxref Foot or service brakes distance shall, at all times, be . (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. Establish an initial brake temperature before the first brake application of 130 to 150 F. Make three stops from 30 mph at 10 fpsps for each stop. (Engine may be run up in speed, then throttle closed quickly to attain maximum charge on vacuum assist units.) 1200-1500 RPM. After burnishing, adjust the brakes in accordance with the manufacturer's published recommendations. Each vehicle shall have a brake system indicator lamp or lamps, mounted in front of and in clear view of the driver, which meet the requirements of S5.3.1 through S5.3.5. If the vehicle is equipped with an adjustable engine speed governor, it is adjusted according to the manufacturer's recommendation. Test procedure and sequence. (c) The service brakes shall be capable of stopping each vehicle with a GVWR greater than 10,000 pounds in two effectiveness tests within the distances and from the speeds specified in S5.1.1.2 and S5.1.1.3. A straight truck or bus air brake system would not leak at a rate of more than how many PSI per . Active Member. Comments are moderated and may not appear for 24 hours or more. Make six stops each from 60 mph, to achieve the average deceleration for each stop as specified in table III. (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. My bus with air drum brakes all around feels like it can stop in half the distance of the hydraulic brakes. By regularly performing these three tests, you can catch potential problems early and keep your hydraulic system running smoothly. Stops, other than spike stops, are made without any part of the vehicle leaving the roadway. Advanced Member, BJ Henderson 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. Heres how to test your hydraulic brakes for leaks: 1. Spring pressure c. Air pressure d. Any of the above 2. b. Record the maximum control force for each stop. Attain the required deceleration within 1 second and, as a minimum, maintain it for the remainder of the stopping time. force and hold while checking hydro-boost hose fittings for leaks. Pump the brakes until the . Hydraulic Brake Check With the engine running, apply the foot brake and hold for five seconds. S6.14 Special drive conditions. %PDF-1.4 % Here in Ontario it is all over the map. What is the Most Common Problem in a Brake Hydraulic System? 0000000656 00000 n Have you ever wondered why trucks and buses make those funny squeaking and hissing sounds? Its a 34' Freightliner Thomas. The letters and background of a single common indicator shall be of contrasting colors, one of which is red. S6.2.6 A vehicle equipped with electrically-actuated service brakes also performs the following test series. The most important thing is the amount of pressure that is being applied to the pedal. guide. 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. If its low, top it off and bleed the brakes according to the manufacturers instructions. Start the engine and run at idle speed. Control force readings may be terminated when vehicle speed falls to 5 mph. Fastback Top Member 1500 Posts Posted - 04/03/2010 : 04:59:49 AM If the pedal sinks down, this indicates that there is a leak in the system and it needs to be repaired before use. 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. information or personal data. Negative for hydraulic brakes- Most brake fluid is hyrdoscopic, which lowers the boiling point of the fluid. (2) Before or upon application of 50 pounds of control force upon a fully manual service brake. The service brakes shall be capable of stopping each vehicle in two fade and recovery tests as specified below. trailer They usually always have air ride suspension on the rear that auto levels to what is needed. Determine whether the brake system indicator lamp is activated when the RBS is disconnected. If batteries are replaced rather than recharged, each replacement battery shall be charged and measured for state of charge in accordance with these procedures. No recharging is allowed after start of test. Snub means the braking deceleration of a vehicle from a higher reference speed to a lower reference speed that is greater than zero. Immediately upon reaching that speed make five stops, each from 30 mph at 10 fpsps for each stop. Except as provided in 5.2.2, the parking brake system on a passenger car and on a school bus with a GVWR of 10,000 pounds or less shall be capable of holding the vehicle stationary (to the limit of traction on the braked wheels) for 5 minutes in both a forward and reverse direction on a 30 percent grade. (a) Permanently affixed, engraved, or embossed; (b) Located so as to be visible by direct view, either on or within 4 inches of the brake fluid reservoir filler plug or cap; and. 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 material and type of lining varies with expected duty cycle and manufacturer. 58 0 obj<>stream Make five stops from 30 mph at 10 fpsps for each stop. If you work for a Federal agency, use this drafting Bendix Hydro-Max Brake System Inspecting 1. Periodic adjustment to manufacturer specifications is required. The brakes shall be adjusted three times during the burnish procedure, in accordance with the manufacturer's recommendations, after 125, 250, and 375 snubs. The pedal should not move. Turn the bus off. Effectively, the engine works backwards by creating negative torque. 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. S6 Test conditions. 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. Burnish stops are conducted on any surface. 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. S7.4.1 Vehicles with GVWR of 10,000 lb or less. 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. Move the bus forward at approximately 5 miles per hour. If at a snub condition of 40 to 20 mph, the temperature of the hottest brake exceeds 550 F, make the remainder of the 35 brake applications from the snub condition without regard to brake temperature. First, make sure that your tires are properly inflated and have good tread. FAR). The third test is a leaks check. learn more about the process here. (a) The service brakes shall be capable of stopping each vehicle with a GVWR of less than 8,000 pounds, and each school bus with a GVWR between 8,000 pounds and 10,000 pounds in four effectiveness tests within the distances and from the speeds specified in S5.1.1.1, S5.1.1.2, S5.1.1.3, and S5.1.1.4. 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. 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. 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. S7.4.2.1 Burnish. https://www.facebook.com/home.php?sk=group_212311114614&ap=1. Once you have confirmed that there are no leaks, you can proceed to pump the pedal harder and faster until you reach full pressure. At completion of 10 spike stops, make six effectiveness stops from 60 mph. (when the temperature of components on both ends of an axle are averaged). S7.13 Service brake system - second fade and recovery test. Bookmarked content can then be accessed anytime on all of your logged in devices! contact the publishing agency. They're most efficient when the engine is at high speed and in a low gear, such as . 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 . Park your car on level ground and set the parking brake. A school bus shall not a. Determine whether the brake system indicator lamp is activated when the electrical power source to the antilock or variable proportioning unit is disconnected. S5.1.5 Water recovery. 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. For children who are going to be sitting down in the classroom for most of the day, this helps them to do more physical activities. Start with the basics The simple hydraulic disc brake system consists of a pedal and linkage to activate the power booster, which in turn activates the master cylinder; disc brake components include caliper, anchor place, shoe and lining and hub and rotor. 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. Air Brakes - They just plain Sound Bad-Ass!! 0000004353 00000 n S6.2.5 For tests conducted in neutral, the operator of an EV with no neutral position (or other means such as a clutch for disconnecting the drive train from the propulsion motor(s)) does not apply any electromotive force to the propulsion motor(s). 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. If the pedal sinks slowly or feels spongy, there may be a leak in one of the hoses or seals. Texas Air Brakes CDL Practice Test. S6.13 Control forces. Need to Pass your CDL School Bus Endorsement Test! 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. 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. 0000002585 00000 n The test takes place with the 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. However, if everything seems normal, congratulations your hydraulic brakes are in good shape! Then start here with FREE Practice Tests for Commercial Drivers. Again, hold your foot on the pedal for a few seconds before releasing it. 3 2) Safety procedures usually require the bus driver to use wheel chocks during the air brake check. switch to drafting.ecfr.gov. Leave an interval of 30 s between snubs (start of brake application to start of brake application). 9, 2004. S7.10 Service brake system - inoperative brake power unit or brake power assist unit test. (b) At vehicle speeds above 20 mph, one wheel on any axle or two wheels on any tandem may lock up for any duration. pressure to operate the bus. The flow switch is the switch on the booster side of he brake system. Then, for any vehicle, make six stops from 60 mph. (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. Load the vehicle to GVWR, release parking brake, and place the transmission selector control to engage the parking mechanism. Other considerations Weight is an important consideration when brakes are being discussed. 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. In Florida, anything that has an Air Brake option is so equipped. Apply the brake pedal with approximately 100 lbs. (b) The indicator lamps need not be activated when a starter interlock is in operation. Each vehicle shall be capable of completing all performance requirements of S5 without -. Are their school bus drivers that prefer one over the other? B. This blog post will provide detailed information on how to properly conduct a hydraulic brake test on a school bus. Is it true that air brakes cost less to maintain? 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. Apply and hold the service brakes for a minute. Second, use your emergency brake. TEST 3: Service brake warning system test. Repeat S7.7.1 or S7.7.2 as applicable except with the vehicle at lightly loaded vehicles weight or at 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. 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). Background and more details are available in the S7.7.1.2 Drive the vehicle, loaded to GVWR, onto the specified grade with the longitudinal axis of the vehicle in the direction of the slope of the grade, stop the vehicle and hold it stationary by application of the service brake control, and place the transmission in neutral. Tail Lights/Brake Lights - clean, not missing or broken . Brake power assist unit means a device installed in a hydraulic brake system that reduces the operator effort required to actuate the system, and that if inoperative does not prevent the operator from braking the vehicle by a continued application of muscular force on the service brake control. Automatic adjusters must remain activated at all times. Where I live (BC Canada) need a special addition to my license for air brakes so I went with hydraulic brakes on my bus. @WXhP|kk=_BW. S6.4 Transmission selector control. By taking care of these things ahead of time, you can avoid potential issues later on. I'd hate to be stuck driving or riding in a bus when its hydraulic breaks crap out and fail to stop the bus. Period inspections required Disc brakes don't require adjustment since the clearance is maintained by the movement of the caliper piston. The above 2. b remainder of the hoses or seals power unit brake. 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