310.001 - Air-Brake System Inspection.pdf

TRAINING AND EQUIPMENT MANUAL APPARATUS 310.001 AIR-BRAKE SYSTEM INSPECTION EFFECTIVE: OCTOBER 2007 Current Revision Date: 01/07/21 Author’s Name/Rank: Robert J. Garcia, Engineer Leslie Oulashian, Management Analyst II Administrative Support: Next Revision Date: Review Level: 01/07/26 1 PURPOSE The...

TRAINING AND EQUIPMENT MANUAL APPARATUS 310.001 AIR-BRAKE SYSTEM INSPECTION EFFECTIVE: OCTOBER 2007 Current Revision Date: 01/07/21 Author’s Name/Rank: Robert J. Garcia, Engineer Leslie Oulashian, Management Analyst II Administrative Support: Next Revision Date: Review Level: 01/07/26 1 PURPOSE The purpose of this policy is to instruct Fresno Fire Department (FFD or Department) members on the correct procedures for checking air-brake systems. APPLICATION To ensure proper operation and to determine if the brakes are within acceptable adjustment tolerance, air-brake systems will be checked daily in accordance with this policy. OPERATIONAL POLICY All front-line emergency response apparatus equipped with air-brake systems shall have these systems inspected on a daily and weekly basis. Completion of the test procedure, together with the results of the test, shall be noted on Administrative Manual Section 106.023, Pre-Trip Inspection Report (FD-03) form and Section 106.029, Emergency Equipment Weekly Inspection Report (FD-11) form. Note: For information on checking Department response vehicles with hydraulic-brake systems, refer to Training and Equipment Manual, Section 310.001a, Hydraulic-Brake System Inspections. OPERATIONAL GUIDELINE Routine monitoring of air-brake systems may assist in indicating existing or potential brake problems such as broken or cracked brake drums and rotors, broken or ineffective brake springs, excessive lining wear, marginal or defective valves, air chambers, etc. Section 310.001 Page 1 of 12 There are two basic designs of air-brake systems used on Department apparatus: ‘S’ cam and disc. Some apparatus may be equipped with disc brakes on the front axle and ‘S’ cam on the drive axle. PROCESS Department policy requires all air tank reservoirs to be drained weekly. In addition to draining the tanks, there are 11 brake tests identified by the California Commercial Drivers Handbook (CCDH), which must be completed daily. Brake tests should be performed outside whenever possible and in a well-ventilated area. A synopsis of the 11 brake tests and the air tank reservoir draining process follows: 1. (C) Governor Cut-In: Not lower than 85 psi. 2. (O) Governor Cut-Out: 110 to 130 psi. 3. (L) Low-Pressure Warning: 60 psi. 4. Service Air Leakage (Applied Test): Less than three psi in one minute. Note: COLA = Items that must be demonstrated during DMV testing. 5. Reservoir Leakage (Static Test): Less than two psi in one minute. 6. Park Brake Valve: Push/pull valve operates between 20 and 45 psi. 7. Inspection: Inspect brake drums, disks, linings, and hoses. 8. 9. Rate of Air Pressure Buildup: 85 up to 100 psi within 45 seconds. Brake Service: Service brake application at five mph. Section 310.001 Page 2 of 12 10. Park Brake Test: Must stop vehicle while rolling below five mph. 11. Check Adjustment: Brake adjustment check at 90 psi. Draining Air Tank Reservoirs: Air tank reservoirs of all apparatus equipped with air brakes are to be drained and refilled to operating air pressure during the weekly emergency equipment checks. 1. Open drain/petcock slowly. 2. Expel moisture from the tank. 3. Once no remaining moisture is visible, close valve completely. 4. Close drain/petcock and refill air tank reservoirs to operating pressures. Brake Tests: Test 1 – Governor Cut-In Test: 1. Start with engine idling and parking brake set. 2. Pump brake slowly to reduce air reservoir pressure. 3. Watch the air pressure gauge to note when the compressor cuts in. 4. Pressure should begin to build at or above 85 psi. Test 2 – Governor Cut-Out: 1. Continued from Test 1. 2. Using fast idle is OK and may reduce pressure build-up time. 3. Governor should cut out at correct pressure (110 to 130). Section 310.001 Page 3 of 12 Test 3 – Low-Pressure Warning: 1. Make light brake applications until pressure drops below 60 psi. 2. Low-pressure warning light or buzzer should go on at or above 60 psi. Note: Engine stopped, ignition on, park brake off, wheels chocked. Test 4 - Reservoir Leakage: 1. Allow pressure to stabilize for at least one minute. 2. Observe the dash gauge pressures for one minute. a. A pressure drop of two psi within one minute is allowable for either service reservoir. Note: Foot brake released, engine stopped, parking brakes applied. Test 5 – Service Air Leakage: 1. Make and hold brake application. 2. Allow pressure to stabilize for one minute, begin timing for one minute while watching the gauges for a pressure drop. A pressure drop of three psi within one minute is allowable for either service reservoir. Note: Full reservoir pressure, engine stopped, parking brakes released. Test 6 – Park-Brake Valve: 1. Make light brake applications until push/pull valve pops out. The normal limits are between 20 and 45 psi. Note: Full reservoir pressure, engine stopped, parking brake off, wheels chocked. Section 310.001 Page 4 of 12 Test 7 – Inspection Test: 1. Free of oil and grease. 2. Minimum 1/4 inch of brake shoe material and 1/8-inch disc pad material. 3. No significant cracks. 4. Check general condition of all components. Test 8 – Rate of Air Pressure Build-up: 1. Parking brake set. 2. Engine at fast idle. 3. Pump brake to drop pressure below 85 psi. 4. Pressure should build from 85 to 100 psi within 45 seconds. Test 9 – Service Brake Application: 1. Full air brake psi in system. 2. While traveling approximately five mph, apply brakes firmly. 3. Check for pulling to one side, unusual feel or sound. Test 10 – Parking Brake Test: 1. Place the transmission in a forward-drive mode. 2. Allow vehicle to move slowly forward (under five mph) and apply the parking brake. 3. If vehicle fails to stop, the parking brake is not operating properly and needs attention. Section 310.001 Page 5 of 12 Test 11 – Brake Adjustment Check: 1. ‘S’ Cam Systems: a. Chock Wheels. b. Fully charge air system until cut out is achieved and turn engine off. c. Release parking brake. d. Verify that pressure is at 100 psi in all tanks. If necessary, make very slight foot pedal applications to achieve 100 psi.. e. With the brakes released, mark the push rod where it exits the chamber, or measure from rear of chamber to one of the clevis pins as a reference point. Have an assistant apply and hold the brakes on full application. Measure the distance the mark traveled. If clevis pin was used, measure from rear of chamber to clevis pin again. The distance the mark traveled or the difference between the two clevis pin measurements is the brake rod travel (See Figures 1 - 3). Figure 1 Section 310.001 Page 6 of 12 Ref #3 Ref #2 Static: Ref #1 = Ref #2 = Ref #3 = Brakes released 0” 2 ¾” 4 1/8’ Ref #1 Figure 2 Applied: 100 psi application Ref.#1= 1 1/2”. Actual brake rod travel Ref #2 = 3 ¼”.3¼” applied – 2 ¾” static = 1 ½” brake rod travel. Ref #3 = 5 5/8”. 5 5/8” brake rod travel applied – 4 1/8 static = 1 ½” Ref #3 Ref #2 Ref #1 Figure 3 Section 310.001 Page 7 of 12 f. Allowable tolerances are as follows: I. 24-inch brake chamber = 1 ¾ inches maximum allowable travel. II. 30-inch brake chamber = 2 inches maximum allowable travel. III. 30-inch-long stroke brake chamber = 2 ½ inches maximum allowable travel. g. The automatic slack adjuster will adjust when the slack adjuster senses excessive travel. If your measurements exceeded the maximum allowable travel during the test, the follow process can remedy the problem in most cases: I. Apparatus chocked. II. Brakes released. III. Allow apparatus to build air and just before “cut out” make a full brake application. IV. Repeat this same approximately 6-12 times. Note: Each ratcheting of the adjuster during this process will decrease the brake rod travel by approximately 1/32 of an inch. h. Recheck brake adjustment. i. If not within the allowable tolerances notify the Fleet Maintenance Facility that the brakes are out of adjustment Section 310.001 Page 8 of 12 2. Free Play Method: The method will be the same as the previous process except instead of having an assistant make the 100-psi application, a bar is inserted into the slack adjuster (See Figure 4). The automatic slack adjuster is designed, when installed and functioning properly, to maintain 5/8” – 3/4” of free play. Free play of more than 1 inch and less than 3/8 inch will require contact with the Fire Shop. More than 1 inch of free play and the brake rod travel when applied at 100 psi will be too great and if less than 3/8-inch free play, the brakes could be dragging. Figure 4 Section 310.001 Page 9 of 12 3. Disc Brake System: When the pads are new, the end of the visual wear indicator (See Figure 5) will protrude past the edge of the housing casting. As the pads wear, less and less of the indicator will be visible past the edge of the casting. When at the last increment (See Figure 6) which is approximately 3/16" protrusion, this indicates 75% wear and the Fire Shop needs to be contacted, and the engineer should be guided by the recommendations of the Fire Shop based upon their findings after a visual inspection and measurement. It is paramount the Fire Shop's findings and future service plan (if developed) be recorded on the back of the apparatus' FD-3. Note: The plastic visual wear indicator is to be used only as a guideline for field measurement of the thickness of the brake pad lining. Due to the wear indicator design, it may not accurately reflect the thickness of the brake pad. Section 310.001 Page 10 of 12 Figure 5 Figure 6 In the event the braking system fails any of the above criteria, the company officer is to immediately place the apparatus out of service and notify his/her respective battalion chief and the Fire Shop for instructions. Refer to Training and Equipment Manual, Section 310.009, Pre-Trip Inspection for additional out-of-service criteria. Section 310.001 Page 11 of 12 INFORMATION This section intentionally left blank. DEFINITIONS This section intentionally left blank. CROSS-REFERENCES California Commercial Driver Handbook Title13 of the California Code of Regulations, Article 1245 (K) Meritor Maintenance Manual MM-0467 Administrative Manual Section 106.023, Pre-Trip Inspection Report (FD-03) Section 106.029, Emergency Equipment Weekly Inspection Report (FD-11) Training and Equipment Manual Section 310.001a, Hydraulic Brake System Inspections Section 310.009, Pre-Trip Inspection Section 310.001 Page 12 of 12