HomeMy WebLinkAbout310.001 - Air-Brake System Inspection
TRAINING AND EQUIPMENT MANUAL
APPARATUS
310.001 AIR-BRAKE SYSTEM INSPECTION
EFFECTIVE: OCTOBER 2007
Current Revision Date: 01/07/21 Next Revision Date: 01/07/26
Author’s Name/Rank: Robert J. Garcia, Engineer Review Level: 1
Administrative Support:
Leslie Oulashian,
Management Analyst II
Section 310.001
Page 1 of 12
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
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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. Rate of Air Pressure Buildup: 85 up to 100 psi within 45 seconds.
9. Brake Service: Service brake application at five mph.
Section 310.001
Page 3 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
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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 5 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 6 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 7 of 12
Figure 2
Figure 3
Static: Brakes released Ref #1 = 0” Ref #2 = 2 ¾” Ref #3 = 4 1/8’
Ref #3 Ref #2
Ref
#1
Ref
#3
Ref
#2
Ref
#1
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”
Section 310.001
Page 8 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
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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 10 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 11 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 12 of 12
INFORMATION
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DEFINITIONS
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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