Workbook

Air Brake Systems

Video Training
Part 1 - 4
Introduction
This workbook is intended for use in conjunction with Parts
1 through 4 of the Bendix video presentation covering the
operation of air brake systems and components. It can be
used as an effective means of taking notes on the more
important points because the material presented is in the
same order as it is viewed. It can also be used as a quiz to
indicate areas requiring further review. Sectional views
and system schematics are taken from the video tape and
all questions can be answered from the material
presented.

For additional copies of this workbook contact your local

Bendix authorized parts outlet and order form BW1678.

The schematics, component drawings and description of

operation presented in the video tapes and in this workbook
are representative only and are presented for the purpose
of training. This material should not be used for design or
application of air brake systems or components without
prior consultation with Bendix Engineering.
Workbook
Air Brake Systems

Video Training
Part 1
Air Generation System
1
Compressor
A. B.
1. Crankshaft
2. Connecting
Rods
3. Rear End C.
Cover
4. Rear Main
Bearing
Journal
5. Pistons
6. Inlet Valves D.
7. Discharge
Valves
G.

E.
F.

Governor

A.
1. Reservoir Port
2. Piston
3. Inlet Exhaust
Valve B.
4. Pressure
Setting Spring
5. Unloader Port

C.

E. D.
 2
Compressor
1. After pressurized oil flows to the connecting rod bearings, it is conducted through an internal oil
passage in the connecting rod to the piston wrist pin.
True False

2. When the compressor piston begins the compression stroke, the inlet valve opens and the discharge
valve closes.
True False

3. Rapid build up of air pressure depends upon proper opening, closing and sealing of both the inlet
and discharge valving and the unobstructed flow of air into the cylinder bores.
True False

4. An obstruction on the air intake side of the compressor (ie; a dirty air filter) can cause compressor
oil passing.
True False

5. An obstruction in the compressor discharge line can cause the compressor to run hot and build
carbon deposits.
True False

6. A slight pressure above the piston causes the compressor inlet valve to open during the intake stroke.
True False

7. Define the term “crankcase flooding” as it applies to the compressor.

Governor
1. Reservoir air enters the governor unloader port and as pressure builds the piston moves down.
True False

2. Air from the governor’s reservoir port flows to the compressor’s unloader mechanism which causes
the compressor to speed up or slow down, depending upon the air requirements of the air system.
True False

3. When supply reservoir pressure drops to the “cut-in” pressure of the governor, typically
100 psi, the governor will exhaust air from the compressor unloader mechanism and system air
pressure will be replenished.
True False

4. The governor’s function in the air system can be summarized by stating that, “it is responsible for
maintaining air brake system pressure between a pre-set maximum and minimum”.
True False

5. During the unloaded cycle of the compressor, with the compressor unloader mechanism pressurized
by the governor, air is “shuttled” from one cylinder of the compressor to the other. This occurs
because the compressor unloader pistons hold the inlet valves off their seats and because the
crankshaft has 180 degrees, opposed connecting rod journals.
True False

6. Describe what would occur if the governor failed to function.

3
Safety Valve
B.
A.
1. Spring
2. Stem
3. Ball Valve
4. Valve Seat C.

D.

Reservoirs and Check Valves

A. B.

1. Supply or Inlet Port

2. Inlet Valve
3. Spring
4. Valve Seat C.
5. Delivery Port

E. D.
 4
Safety Valve
1. Safety valves can be obtained with various settings but are generally set to open and exhaust
at 150 psi.
True False

2. The safety valve is installed in the compressor discharge line.

True False

3. The exposed stem allows the safety valve it to be tested or checked periodically.
True False

4. Working in conjunction with the governor, the safety valve exhausts the air from the discharge line
when the compressor is in the unloaded state (not compressing air).
True False

Reservoirs and Check Valves

1. The single check valve is intended to protect the air pressure in the supply reservoir (the first
reservoir that receives air) in the event air pressure in the service reservoir(s) is lost.
True False

2. The single check valve is located in the discharge line, between the compressor and air dryer.
True False

3. Air flow through a single check valve is in one direction only.

True False

4. The single check valve got its name from the fact that only one is used in the air brake system.
True False

5. A minimum of three reservoirs are generally used in a dual air brake system.
True False

6. The supply reservoir supplies air to the service reservoirs.

True False
5
Dash Gauge and Low Pressure Indicator

Reservoirs and Drain Cocks

 6
Dash Gauge and Low Pressure Indicator
1. The dash gauge is required by federal regulations.
True False

2. Connected to the supply reservoir, the dash gauge provides the driver with a continuous “read out”
of air pressure available for braking.
True False

3. If a single dash gauge is installed, there will be two “hands” or needles on the gauge. One “hand”
indicates available air pressure in the service reservoir and the other registers the air pressure in the
supply reservoir.
True False

4. The low pressure indicator switch is required by federal regulations.

True False

5. A low pressure indicator switch, like the Bendix® LP-3™, is generally mounted on the vehicle dash.
True False

6. When air pressure in the system falls to a preset safe minimum, the low pressure switch will “light
up” and/or begin to “buzz”.
True False

7. The minimum air pressure setting for a low pressure indicator switch is typically 60 psi.
True False

8. If the low pressure indicator is set so that the electrical contacts close at/or below 60 psi, then they
should open immediately when pressure rises above 60 psi.
True False

Reservoirs and Drain Cocks

1. Oil, water and vapor are contained in the air discharged from the compressor and will condense in
the air lines and collect in the reservoirs.
True False

2. The drain cock, installed in the bottom of the reservoir, is used to remove the accumulated
contaminates.
True False

3. The drain cock can be used to test the operation of the low pressure indicator switch and the single
check valve.
True False

4. Once the contaminants are drained from the reservoir and the compressor stops “pumping” air, no
further accumulation of water or contamination will occur.
True False
7
Air Dryer
B. C. D.
E.
A.
1. Supply Port
2. End Cover
3. End Cover Sump F.
4. Oil Separator
5. Desiccant Cartridge
6. Drying Bed
7. Check Valves
8. Outer Shell
9. Delivery Port
10. Turbo-cut-off Valve
11. Control Port
12. Purge Valve Piston

G.

L. I. H.
M. J.
K.
 8
Air Dryer
1. The oil separator removes not only oil droplets, but also removes solid contaminants and remaining
water droplets.
True False

2. The desiccant material in the air dryer removes water vapor in a process known as adsorption.
True False

3. Water and contaminants are collected in the purge volume and are expelled during the purge cycle
of the air dryer.
True False

4. The check valve above the desiccant cartridge prevents the loss of air brake system pressure during
the purge cycle of the air dryer.
True False

5. The turbo cut-off-valve in the air dryer prevents the loss of engine turbo charger pressure through
the open purge valve of the air dryer during the purge cycle.
True False

6. The air dryer requires about 25 seconds to complete the purge cycle.
True False

7. Name the three air connections on the air dryer. Where and to what are they connected?

8. What is the purpose of the small orifice (hole) next to the check valve in the top of the
desiccant cartridge?

9. Give one reason why the air dryer would constantly “cycle” between the charge and purge.
9

Air Supply System

1. Using the symbols shown in the schematic, draw the Low Pressure Indicator Switch, Safety Valve,
Single Check Valve(s) and Dash Gauge(s) in their correct positions.

2. Draw in the air lines that connect the Compressor, Air Dryer, Governor and Reservoirs.

3. Indicate with an arrow and the number “3” air line(s) NOT CONSTANTLY filled with air pressure
during normal vehicle operation.
Workbook
Air Brake Systems

Video Training
Part 2
Service Brake System
11
Dual Brake Valve
D.
1. Pedal or Treadle B. C. E.
2. Plunger A.
3. Roller
4. Stop Button
5. Fulcrum Pin F.
6. Spring Seat
7. Graduating Spring
8. Primary Piston G.
9. Primary Inlet and
Exhaust Valve
10. Secondary or Relay Piston ➔
11. Secondary Inlet and H.
Exhaust Valve
12. Primary Supply Port
13. Secondary Supply Port I.
14. Primary Delivery Port
15. Secondary Delivery Port J.
16. Exhaust Port
K.

P. L.
M.
O. N.

Brake Chambers and Spring Brakes

B. C.
A.
1. Inlet Port
2. Return Spring
3. Diaphragm
4. Push Plate
5. Push Rod

E. D.
 12
Dual Brake Valve
1. Generally all dual brake valves function the same way. The method of mounting in the vehicle can
differ. The E-6™ dual brake valve is a fire wall mounted unit.
True False

2. With the brakes released, both the primary and secondary inlet valves are __________ (open
closed) and both exhaust valves are __________ (open closed).

3. When a brake application is first made, the primary or rear axle service circuit begins to deliver air
ahead of the secondary or front axle service circuit.
True False

4. The secondary or front axle service circuit of the dual brake valve is controlled by the air delivery
from the primary circuit.
True False

5. In the balanced position, both the primary and secondary inlet valves are __________ (open closed)
and both exhaust valves are __________ (open closed).

6. When the brake valve treadle is fully depressed, as in a “panic stop”, both the primary and second-
ary inlet valves are held open mechanically and full reservoir pressure is delivered to the brakes.
True False

7. What is the function of the primary piston graduating spring?

Brake Chambers & Spring Brakes

1. The number designation given to a brake chamber provides information about its “power” potential.
True False

2. What does the number designation given to a brake chamber actually mean?

3. The purpose of the brake chamber return spring is to “delay” or slightly reduce the force of the brake
application in order to help balance the vehicle brakes.
True False

4. The service section of a spring brake functions and operates the same as a standard brake cham-
ber.
True False

5. What would the force be, (measured at the end of the push rod) if 30 psi air pressure was applied to
a Type 20 brake chamber?

6. Spring Brakes can be used interchangeably with brake chambers, but are most often found on the
front axle of the vehicle.
True False

7. What is attached to the end of the brake chamber push rod?

13
Slack Adjuster

Quick Release
B.
A.
1.Inlet or Supply Port
2.Delivery Ports
3.Diaphragm
4.Exhaust Port

C.

E. D.
 14
Slack Adjuster
1. Although most often used on “S” cam foundation brakes, the slack adjuster can also be found on the
less often encountered Wedge type foundation brakes.
True False

2. Describe as many of the basic functions of the slack adjuster as you can.

3. The number designation of the slack adjuster indicates the brake chamber number that is used with
it. For instance; a type 20 slack adjuster should always be used with a type 20 brake chamber.
True False

4. If you answered TRUE in question 3, explain why.

If you answered FALSE in question 3, then explain what the slack adjuster number designation means.

5. The Bendix® ASA-5™ is an automatic slack adjuster.

True False

6. One important feature of the ASA-5™ automatic slack adjuster is that it constantly adjusts the brakes
in very small increments each time the brakes are released.
True False

7. The ASA-5™ automatic slack adjuster monitors brake chamber stroke and will adjust the brakes
when the stroke increases due to lining wear.
True False

Quick Release Valve

1. As air line length increases and air pressure decreases, the time required for air to return to the
brake valve and exhaust to atmosphere will increase.
True False

2. A quick release valve, such as the Bendix® QR-1™ or QR-N™, is used to increase the time it takes to
release the brakes.
True False

3. Quick release valves can be used in several locations on the vehicle, however, one of the most
common is on the front axle.
True False

4. In addition to increasing release times for the brakes, the quick release also speeds up the
application of the brakes during emergency situations.
True False
15
Relay Valve
B. C.
A.
1. Relay Piston
2. Exhaust Port
3. Inlet and
Exhaust
Valve Assembly
4. Service or
Control Port
5. Delivery Port
6. Supply Port

F. D.
E.

Stop Light Switch

B. C.
A.
1. Cover
2. Piston
3. Diaphragm
4. Contact Strip
5. Terminals
6. Shorting Bar
7. Inlet Port

G. D.

F. E.
 16
Relay Valve
1. Relay valves, such as the Bendix® R-12™, are usually installed on or near the rear axle(s), especially
on long wheel base vehicles. The function of the relay valve is to assure the simultaneous applica-
tion and release of the brakes most distant from the brake valve.
True False

2. Brake application pressure from the foot brake valve enters the R-12™ relay valve supply port and is
conducted directly to the under side of the piston.
True False

3. With the brakes released the inlet valve is __________ (open closed) and the exhaust valve is
__________ (open closed).

4. In the Balanced position, the inlet valve is __________ (open closed) and the exhaust valve is
__________ (open closed).

5. When the R-12™ relay valve is in the Holding or Balanced position, the foot brake valve is also in the
Holding or Balanced position.
True False

6. It is best to replace a relay valve with the same or similar unit since different crack pressures are
sometimes used. Different crack pressures can affect brake application timing.
True False

7. Crack pressure is the amount of control air pressure needed to open the inlet valve.
True False

8. The standard R-12™ relay valve has a crack pressure of approximately 4 psi.
True False

Stop Light Switch

1. The Bendix® SL-5™ stop light switch will activate the vehicle stop lights when brake application
pressure reaches or exceeds;
A 10 psi
B 6 psi
C 5 psi
D 2 psi

2. The Bendix® SL-5™ stop light switch can be repaired using a maintenance kit, available from any
authorized parts outlet.
True False
17

E-6“
Brake
ASA-5“ Auto Valve
Slack Adjuster
R-12“
Relay
Valve
QR-1“
Quick
Release

Service Brake System

1. Using the symbols shown in the schematic, draw the Low Pressure Indicator Switch, Safety Valve,
Single Check Valve(s), Dash Gauges and Stop Light Switch, in their correct positions.

2. Draw in the air lines that connect the Compressor, Air Dryer, Governor, Reservoirs, Brake
Chambers, Spring Brakes, Quick Release Valve, Brake Valve and Relay Valve.

3. Indicate with an arrow and the number “3”, the air lines that ARE NOT filled with air pressure when
the brakes are released.
Workbook
Air Brake Systems

Video Training
Part 3
Emergency and
Parking Brake System
19
Double Check Valve
B.
A.
1. Shuttle
2. Guide
3. Body
4. Inlet Ports
5. Delivery Port

C.

F. D.
E.

PP-1™ Push Pull Control Valve

B. C.
A.
1. Control Button
2. Plunger
3. Spring
4. Inlet & D.
Exhaust Valve
5. Body
6. Supply Port
7. Delivery Port
8. Exhaust Port
➔ E.

H.

G. F.
 20
Double Check Valve
1. Briefly explain the function and operation of the double check valve.

2. Double check valves can be used in a number of different ways in the air brake system. Describe
how the double check shown in the video was used and what it was connected to.

3. In your own words, explain why the double check valve should be mounted horizontally (shuttle
moving back and forth rather than up and down) when the difference in air pressure at the inlet
ports is minimal.

PP-1™ Push Pull Control Valve

1. The PP-1™ push pull control valve button will automatically go in or pop out depending upon the
available system pressure supplied to it.
True False

2. The PP-1™ is an on-off control valve, it does not modulate or graduate air pressure.
True False

3. With the button IN (plunger into body as far as it will go) the PP-1™ valve is in the exhaust position.
True False

4. The PP-1™ valve is available in a range of automatic settings, from about 20 psi to 60 psi.
The typical setting is 40 psi.
True False

5. When supply pressure falls to the automatic setting of the PP-1™ valve, the valve will move to the
EXHAUST position.
True False
21
Spring Brakes
B. C.
A.
1. Piggyback
2. Service
Diaphragm
3. Push Plate D.
4. Emergency
Piston
5. Emergency
Diaphragm
6. Emergency Spring
7. Emergency Air
Inlet Port
8. Service Inlet Port

H. E.

G. F.

R-14™ Spring Brake Relay Valve

B. C.
A.
1. Delivery Port
2. Service or
Control Port
3. Supply Port D.
4. Balance Port
5. Inlet and
Exhaust Valve
6. Relay Piston
7. Diaphragm
E.

G. F.
 22
Spring Brakes
1. The spring brake performs three braking functions on the vehicle. In addition to performing the
normal service braking it also is the parking and __________ brake for the vehicle.

2. The two sections of the spring brake use air pressure in an opposite manner. Air pressure applied to
the emergency section applies the brakes, while air taken away from the service side releases the
brakes.
True False

3. A release bolt is used in the emergency, or “piggyback”, section to cage the large, emergency
spring.
True False

4. During a park or emergency application of the brakes, the expanding emergency spring supplies the
force necessary to apply the brakes and holds them applied regardless of loss of air pressure in the
brake system.
True False

R-14™ Spring Brake Relay Valve

1. The bottom half (body) of Bendix® R-14™ relay valve is exactly like the R-12™ relay valve and is
interchangeable. The difference between the two valves is the cover.
True False

2. Although it can be used as a service relay, the R-14™ relay valve is used primarily as a spring brake
relay. It provides rapid application and release of the parking and emergency brakes.
True False

3. The service or control port of the R-14™ spring brake relay valve is connected to the delivery of the
__________ control valve.

4. In your own words describe what the term “anti-compounding” means.

5. The balance port of the R-14™ relay valve is connected to the delivery side of the R-12™ service
relay valve.
True False
23
SR-1™ Spring Brake Valve
B. C. D.
A.
1. Piston “A”
2. Piston “B”
3. Inlet/Exhaust
Valve “A”
4. Inlet/Exhaust
Valve “B”
5. Spring “A”
6. Spring “B”
7. Single Check Valve

G. E.
F.
 24
SR-1™ Spring Brake Valve
1. The primary function of the SR-1™ spring brake valve is to maintain modulated rear axle braking if
primary reservoir pressure is lost.
True False

2. The SR-1™ spring brake valve is used on longer wheel base vehicles, but can be used on straight
trucks and tractors.
True False

3. The SR-1™ spring brake valve has four air connections, match the valve ports to the components
connected to them.
No. 1 Reservoir Port _______ A. Supply Reservoir
Control Port ______________ B. Rear Service Reservoir
Supply Port ______________ C. Front Service Reservoir
Delivery Port _____________ D. Rear Axle Delivery of Foot Valve
E. Front Axle Delivery of Foot Valve
F. Spring Brake
G. Delivery of PP-1™ Push Pull Control Valve
H. R-14™ Valve Control or Service Port

4. When rear axle service reservoir (primary reservoir) pressure is lost, the SR-1™ spring brake valve
will modulate the pressure in the spring brake emergency section and the rear brakes will be applied
with spring force rather than air pressure.
True False

5. The SR-1™ spring brake valve allows the foot brake valve to apply and release (modulate) the spring
brakes when primary reservoir pressure is lost.
True False
25

PP-1™
Push Pull Control Valve
SR-1™ Spring
Brake Valve

E-6™
™
ASA-5 Auto Brake
Slack Adjuster Valve
R-12™ R-14™
Relay Relay
Valve Valve

QR-1™
Quick
Release

Emergency and Parking Brake System

1. Using the symbols shown in the schematic, draw the Low Pressure Indicator Switch, Safety Valve,
Single Check Valve(s), Dash Gauge(s), Double Check Valve and Stop Light Switch, in their correct
positions.

2. Draw in the air lines that connect all the air devices.

3. Indicate with an arrow and the number “3” which air lines ARE NOT filled with air pressure when the
service brakes are released and the spring brakes are applied (vehicle parked, engine running).

4. Indicate with an arrow and the number “4” which air lines ARE FILLED with air pressure when both
the service and spring brakes are applied (vehicle parked, engine running, foot brake valve
depressed).
Workbook
Air Brake Systems

Video Training
Part - 4
Tractor/ Trailer
Brake System
27
TP-3™ Tractor Protection Valve

E. A.
1. Plunger
2. Service Valve D.
3. Body
4. Spring
5. Tractor Service Port
6. Tractor Supply Port B.
7. Trailer Service Port
8. Trailer Supply Port G.
H.

F. C.

PP-7™ Trailer Supply Valve

1. Plunger
2. Spring A. N.
3. Inlet & Exhaust Valve
4. Piston
5. Piston Return Spring
6. Inlet & Exhaust Valve
7. Valve Spring
8. Exhaust Vent
9. Supply Port F.
10. Delivery Port J.
11. Control Port D.
12. Exhaust Port
13. Control Button
H. G.
K.
C. M.
B.

E. L.
 28
TP-3™ Tractor Protection Valve
1. Briefly explain the function and operation of the tractor protection valve.

2. The TP-3™ tractor protection valve controls the flow of air through the two air lines that connect the
tractor to the trailer.
True False

3. There are 2 separate valves in the TP-3™ tractor protection valve, one for each of the two air lines
connected to the body.
True False

4. The tractor protection valve is mounted on the dash and has a red control button.
True False

PP-7™ Trailer Supply Valve

1. The PP-7™ trailer supply valve button will automatically go in or pop out depending upon the
available system pressure supplied to it.
True False

2. The PP-7™ trailer supply valve has three (3) air connections. Put the letter of the correct connection
next to the PP-7™ trailer supply valve port shown below.

PP-7™ trailer supply valve Supply port A. Double Check Valve Outlet
PP-7™ trailer supply valve Delivery port B. Tractor Service Port of Tractor Protection
PP-7™ trailer supply valve Control port C. Tractor Supply Port of Tractor Protection
D. Delivery Port of Park Control Valve
E. Rear Axle Delivery of Foot Valve

3. When the driver pulls the PP-7™ trailer supply valve’s control button, the tractor and trailer parking
brakes apply.
True False

4. The PP-7™ trailer supply valve is responsible for charging the trailer air system and opening the
service valve in the TP-3™ tractor protection valve.
True False

5. When the “System Park Control Valve (yellow diamond shaped control button)” is pulled: (Choose as
many as are applicable)
A. Only the tractor parking brakes are applied
B. The tractor and trailer parking brakes are applied
C. Only the Trailer parking brakes are applied
D. Neither A, B, or C above.

6. The PP-7™ trailer supply valve is actually two valves in a single housing. One of the valves is called a
“synchro” or synchronizing valve and the other is:
A. Relay Valve
B. Brake Valve
C. Push-Pull Valve
D. SR-1™ Spring Brake Valve

7. The yellow, diamond shaped control button easily identifies the PP-7™ trailer supply valve on the
vehicle dash.
True False
29

DS-2™ Double Check Valve and Stop Light Switch

B.

1. Inlet Port
2. Inlet Port
3. Outlet Port
4. Shuttle
5. SL-5™ Stoplight
Switch

C. D.

A. E.
BP-R1™ Bobtail Proportioning Relay Valve

1. Supply Port
2. Delivery Ports
3. Service or Control Port for the Relay
4. Control Port for the Proportioning Valve
5. Body
6. Cover D. A. B.

E. F. C.
 30
DS-2™ Double Check Valve and Stop Light Switch
1. The DS-2™ double check valve has three (3) air connections on it. Put the letter of the correct
connection next to the PP-7™ trailer supply valve port shown below.

DS-2™ double check valve Inlet Port A. Delivery of the R-12™ service relay valve
DS-2™ double check valve Inlet Port B. Delivery of the front axle circuit of the foot valve
DS-2™ double check valve Outlet Port C. Delivery of the hand valve
D. Delivery of the rear axle circuit of the foot valve
E. The inlet or supply port of the R-12™ relay valve
F. The tractor supply port of the tractor protection valve
G. The tractor service port of the tractor protection valve

2. The function of the Double Check Valve portion of the DS-2™ is;

BP-R1™ Bobtail Proportioning Relay Valve

1. Explain briefly what function the BP-R1™ relay valve performs.

2. The BP-R1™ relay valve is the combination of two separate valves in one body; an R-12™ relay valve
and a proportioning valve.
True False

3. The BP-R1™ relay valve replaces the standard service relay valve on the vehicle.
True False

4. There are four “types of air connections” on the BP-R1™ relay valve. Put the letter of the correct
connection next to the PP-7™ trailer supply valve port shown below.
BP-R1™ relay valve Supply Port A. The service brake chambers
BP-R1™ relay valve Delivery Port B. The delivery of the PP-7™ trailer supply valve
™
BP-R1 relay valve Service Port C. The delivery of the Front Axle Circuit of the foot valve
BP-R1™ relay valve Control Port D. The delivery of the Rear Axle Circuit of the foot valve
E. The Tractor Service Port of the tractor protection valve
F. The inlet of the front axle proportioning valve
G. Front axle Service Reservoir
H. Rear axle Service Reservoir

5. The BP-R1™ relay valve can replace the standard service relay on any vehicle and will reduce
application pressure to the front axle brakes during “panic stops”.
True False

6. During tractor - trailer operation the BP-R1™ relay valve reduces pressure to the tractor rear brakes and
thereby stabilizes the entire combination during each stop. When operating in the “Bobtail” mode the
BP-R1™ relay valve will allow full braking pressure to reach the tractor’s rear service brakes.
True False
31
SR-5™ Trailer Spring Brake Valve

1. Relay Piston
2. Inlet and Exhaust Valve
3. Single Check Valve
4. Single Check Valve
5. Single Check Valve
6. Single Check Valve
7. Pressure Protection Valve
8. Service Reservoir Port
9. Service Reservoir Mounting Stud
10. Trailer Supply Port
11. Trailer Service Port
12. Delivery Ports J.
A. B. C.

E.

H.
G.
K. L.

M.
F. D.
 32
SR-5™ Trailer Spring Brake Valve
1. The primary function of the SR-5™ trailer spring brake valve is to control the application and release
of trailer spring brakes.
True False

2. If trailer reservoir pressure is lost, the SR-5™ trailer spring brake valve will automatically apply the
trailer brakes and prevent a run-away.
True False

3. The SR-5™ trailer spring brake valve allows the use of trailer supply line air pressure for trailer
service brake applications when all trailer reservoir pressure is lost.
True False

4. The SR-5™ trailer spring brake valve has five (5) air connections, match the valve ports to the
components connected to them.

Service Reservoir Port A. Trailer Supply Line

Reservoir Mounting Stud B. Trailer Service Reservoir
Trailer Supply Port C. Trailer Service Line
Trailer Service Port D. Service Side of the Trailer Spring Brakes
Delivery Port E. Emergency Side of the Trailer Spring Brakes
F. Control Port on Trailer Service Relay Valve
G. Delivery Port on Trailer Service Relay Valve

5. The SR-5™ trailer spring brake valve will automatically apply the trailer spring brakes in the event of
tractor trailer break away.
True False

6. Like many of the valves presented, the SR-5™ trailer spring brake valve incorporates several indi-
vidual valves in a single housing. In addition to the relay valve at the heart of the SR-5™ trailer spring
brake valve, which of the following are also inside? Circle all that apply.

A. Single Check Valve

B. Double Check Valve
C. Synchro or Synchronizing Valve
D. Pressure Protection Valve
E. Foot Valve
33

DS-2™ Double Check &

PP-7™ Stoplight Switch
Trailer TP-3™ Tractor
Supply Valve Protection
Service “Glad Hand”

Brake
Chamber Supply “Glad Hand”

E-6™ Brake
PP-1™ Control Valve
Valve

QR-1™
Quick
Release Air
Dryer BP-R1™ R-14™
Bobtail Relay
Relay Valve

Governor

Spring
Compressor Brake

Tractor Air Brake System

1. Draw in the air lines that connect all the air devices.

2. Indicate with an arrow and the number “2” which air lines ARE NOT filled with air pressure when the
tractor air system is fully charged to governor cut-out pressure and both the PP-1™ push pull control
valve and the PP-7™ trailer supply valve are PUSHED IN.

3. Indicate with an arrow and the number “3” which air lines ARE FILLED with air pressure when the
tractor air system is fully charged to governor cut-out pressure and the PP-1™ push pull control
valve is PULLED OUT and the PP-7™ trailer supply valve is PUSHED IN.
 34
Service “Glad Hand”

Spring
Brake
Supply “Glad Hand”

SR-5™ R-12™
Spring Brake Relay
Valve Valve

Spring
Brake

Trailer Air Brake System

1. Draw in the air lines that connect all the air devices.

2. Indicate with an arrow and the number “2” which air lines ARE NOT filled with air pressure when the
tractor air system is fully charged to governor cut-out pressure and both the PP-1™ push pull control
valve and the PP-7™ trailer supply valve are PUSHED IN.

3. Indicate with an arrow and the number “3” which air lines ARE FILLED with air pressure when the
tractor air system is fully charged to governor cut-out pressure and the PP-1™ push pull control valve
is PULLED OUT and the PP-7™ trailer supply valve is PUSHED IN.
 35

DS-2™ Double Check & TP-3™ Tractor

Stoplight Switch Protection

PP-7™
Trailer
Supply Valve

E-6™ Brake
Valve
PP-1™ Control
Valve

QR-1™ R-12™
Quick ™
Relay
SR-5 Valve
Release BP-R1™ R-14™ Spring Brake
Bobtail Relay Valve
Relay Valve

Tractor Trailer Air Brake System

1. Connect the air lines to all air brake components on the tractor trailer air brake system.
Workbook
Air Brake Systems

Video Training
Answers Part 1 - 4
37
5. True
Answers for Part 1 Reservoirs and Check
6. True
Valves (Page 3)
Compressor (Page 1) lllustration 7. Supply (In from compressor),
Illustration A. 4 Delivery (Out to supply res.),
A. 6 B. 2 Control (From governor
B. 7 C. 5 unloader port)
C. 5 D. 3 8. Allows purge air (dry air) to
D. 2 E. 1 flow back through the
E. 3 1. False desiccant cartridge. OR Slows
F. 4 2. False the flow of pressurized dry air
G. 1 3. True back through the desiccant
1. False 4. False cartridge allowing it to expand
2. False 5. True to almost 0 psi.
3. True 6. True 9. Air pressure loss in general
4. True anywhere in the system.
5. True Remember loss of pressure in
Dash Gauge & Low
6. False the Supply Reservoir which
Pressure
7. Crankcase flooding is the includes any device, line, or
build-up of an oil level in the Indicator (Page 5)
fitting up to the single check
compressor crankcase. It is lllustration
valve installed in the service
caused by the failure of oil to 1. True
reservoirs, WILL NOT BE
rapidly return to the engine 2. False
REGISTERED ON THE DASH
crankcase from the 3. False
GAUGES.
compressor crankcase. 4. True
5. False
Governor (Page 1)
6. False Answers for Part 2
7. True
lllustration Dual Brake Valve (Page 11)
8. False
A. 4 lllustration
B. 2 A. 10
C. 3 Reservoirs & Drain Cocks
(Page 5) B. 2
D. 1 C. 3
E. 5 1. True
2. True D. 5
1. False E. 1
2. False 3. True
4. False F. 6
3. True G. 4
4. True H. 7
5. True Air Dryer (Page 7)
I. 12
6. System pressure would lllustration
J. 8
continue to rise until the Safety A. 8
K. 9
Valve activated. B. 6
L. 13
C. 7
M.16
Safety Valve (Page 3) D. 5
N. 11
lllustration E. 4
O. 15
A. 1 F. 3
P. 14
B. 2 G. 7
1. False
C. 3 H. 9
2. Closed, Open
D. 4 I. 12
3. True
1. True J. 10
4. True
2. False K. 1
5. Closed, Closed
3. True L. 2
6. True
4. False M.11
7. The Graduating spring
1. True
modulates (graduates,
2. True
feathers ) air delivery in the
3. False
primary or rear axle service
4. False
system.
 38
Brake Chambers & Spring Relay Valve (Page 15) 3. If mounted vertically, the
Brakes (Page 11) Illustration lower inlet port air pressure
lllustration A. 1 would have to be much
A. 2 B. 4 higher than the pressure at
B. 4 C. 3 the top inlet port in order to
C. 3 D. 5 lift the shuttle and seal the
D. 1 E. 2 top inlet. In the horizontal
E. 5 F. 6 position the weight of the
1. True 1. True shuttle rest on the guides
2. The brake chamber type 2. False and a lower pressure differ-
number indicates the 3. Closed, Open ence between the two inlet
effective area of the 4. Closed, Closed ports will allow it to move.
diaphragm. 5. True
3. False 6. True
PP-1™ Push Pull Control (Page 19)
4. True 7. True lllustration
5. 600 pounds force 8. True A. 5
6. False B. 1
7. The clevis or yoke assembly. Stop Light Switch (Page 15) C. 2
The yoke assembly connects D. 3
lllustration
the brake chamber push rod A. 4 E. 7
to the slack adjuster. B. 5 F. 8
C. 6 G. 4
Slack Adjuster (Page 13) D. 1 H. 6
1. False E. 3 1. False
2. Convert linear stroke of F. 7 2. True
brake chamber into rotational G. 2 3. False
motion. Multiplies force 1. B - 6 psi 4. True
developed by brake chamber. 2. False 5. True
Rotates the cam shaft of the
foundation brake.
3. False
Answers for Part 3 Spring Brakes (Page 21)
lllustration
4. False - The number Double Check Valve (Page 19) A. 3
designation of the slack lllustration B. 4
adjuster indicates the amount A. 4 C. 5
of rotational torque the unit B. 5 D. 6
can withstand; a Type 20 C. 4 E. 1
slack adjuster can withstand D. 2 F. 7
20,000 pound inches of E. 1 G. 8
torque. F. 3 H. 2
5. True 1. The double check valve is 1. Emergency
6. False - The ASA-5™ slack a device that receives air 2. False - Air pressure applied
adjuster adjusts on applica- pressure from two sources to the emergency section
tion, prior to the shoes and delivers the higher of releases the brake.
contacting the drum. the two. 3. True
7. False - The ASA-5™ slack 2. The double check in the 4. True
adjuster monitors lining to video was used to maintain
drum clearance. a constant source of air R-14™ Spring Brake Relay
pressure for the parking or (Page 21)
Quick Release Valve (Page 13) emergency brake system. Its lllustration
lllustration inlet ports were connected to A. 6
A. 3 each of the two service B. 4
B. 1 reservoirs and its delivery C. 7
C. 2 was connected to the PP-1™ D. 2
D. 4 control valve and the R-14™ E. 1
E. 2 spring brake relay valve. F. 5
1. True G. 3
2. False - The quick release
valve decreases release time.
3. True
4. False
39
1. True 4. True
2. True 5. B
3. Delivery port of the PP-1™ (push- 6. C
pull) control valve 7. False
4. “Anti-Compounding” refers to a system that
prevents the service and parking DS-2™ Double Check Valve and Stoplight
(emergency) brakes from being applied at Switch
the same time. A 4
5. True B 5
C 1
SR-1™ Spring Brake Valve (Page 24) D 2
A. 1 E 3
B. 5 1. DS-2™ double check valve Inlet Port B
C. 6 DS-2™ double check valve Inlet Port D
D. 2 DS-2™ double check valve Outlet Port G
E. 7 2. Allows operation of trailer brakes after a single
F. 4 failure of tractor service system has occurred
G. 3
1. True BP-R1™ Bobtail Proportioning Relay Valve
2. True A 6
3. No. 1 Reservoir Port to B. Rear Service B 3
Reservoir Control Port to E. Front Axle C 5
Delivery of Foot Valve Supply Port to G. D 4
Delivery of PP-1™ control valve Delivery Port E 1
to H. R-14™ relay valve Control or Service Port F 2
4. True 1. Reduces brake application pressure to rear
5. True tractor brakes during “bobtail” operation
2. True
Answers for Part 4 3.
4.
True
BP-R1™ relay valve Supply Port H
TP-3™ Tractor Protection BP-R1™ relay valve Delivery Port A
A 3 BP-R1™ relay valve Service Port D
B 1 BP-R1™ relay valve Control Port B
C 4 5. False
D 8 6. False
E 6
F 5 SR-5™ Trailer Spring Brake Valve
G 7 A 7 H 6
H 2 B 4 J 8
1. Serves as ON-OFF control for Service or C 5 K 10
Control line running between Tractor and D 12 L 9
Trailer E 11 M 2
2. False F 1
3. False G 3
4. False 1. True
2. False
PP-7™ Trailer Supply Valve 3. False
A 1 G 6 4. Service Reservoir Port B
B 12 H 8 Reservoir Mounting Stud B
C 10 J 9 Trailer Supply Port A
D 3 K 7 Trailer Service Port C
E 11 L 4 Delivery Port E
F 2 M 5 5. True
N 13 6. A, D
1. False
2. PP-7™ trailer supply valve Supply port A
PP-7™ trailer supply valve Delivery port C
PP-7™ trailer supply valve Control port D
3. False
 40

Part 1 Schematic (Page 9)

Part 2 Schematic (Page 17)

41
Part 3 Schematic (Page 25)

Part 4 Schematic (Page 33)

2 2
2
3
2

3 3
3
3
 42
Part 4 Schematic (Page 34)

2
2
2

3
2
 43

Part 4 Schematic (Page 35)

BW1678 © Bendix Commercial Vehicle Systems LLC 11/2004 Printed in U.S.A. All rights reserved.