4207-6, S.

operation & maintenance instruction

SA-26 INDEPENDENT BRAKE VALVE and

SA-26 INDEPENDENT BRAKE VALVE PORTION

July, 1991
Supersedes issue dated July, 1983

NOTE: The following description and

operation is based on this device and
its components being new or this
device and its components having
been repaired, tested, installed and
maintained in accordance with
instructions issued by this and any
other applicable Wabtec Corporation
publications.

WARNING: At the time any part is

replaced in this device, the operation of
the complete device must pass a series
of tests prescribed in the latest issue of
the applicable Wabtec Test Specification.
At the time this device is applied to the
brake equipment arrangement, a
stationary vehicle test must be made to
insure that this device functions properly
in the total brake equipment arrangement.
(Consult your local Wabtec
Representative for identity of the test
specification, with latest revision date, that
covers this device.)

IMPORTANT: Only Wabtec supplied

parts are to be used in the repair of this
device in order to obtain satisfactory
operation. Commercially available non-
O.E.M. parts are unacceptable.

NOTE: The part numbers and their

associated descriptions are the property
of Wabtec Corporation and may not be
replicated in any manner or form without
the prior sole written consent of an Officer
of Wabtec Corporation.

© 2000 WABCO Locomotive Products. A Wabtec Company. All rights reserved

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operation & maintenance instruction

Top View Bottom View

Fu
ll A
pp
lica
tio
7-3/4" n
20 30 13
R. 60
30 Deg.
Deg.
e
as
le
Re

LEGEND
Port Designation 30
30 Main Reservoir 20 13
20 Delivery
13 Actuating
20 30 13

Front View This diagrammatic representation is for functional

analysis only. It is not intended to be used as an
actual physical representation of portion or pipe
bracket configurations.
Figure 1 - Exterior Views Figure 2 - Diagrammatic View

1.0 DESCRIPTION

The SA-26 Independent Brake Valve is comprised of an psi. The portion is designed so that it can easily be removed
The SA-26 Independent Brake Valve Portion and a Pipe from the pipe bracket or manifold to which it is mounted
Bracket. The Pipe Bracket serves as the mounting base for without disturbing the pipe connections. Contact your
the SA-26 Independent Brake Valve Portion. All pipe Wabtec Corporation Representative for the SA-26 Brake
connections are made directly to the Pipe Bracket. This Valve or SA-26 Brake Valve portion for your specific
arrangements permits for the removal of the SA-26 application. The SA-26 Brake Valves and Brake Valve
Independent Brake Valve Portion without disturbing the piping Portions are shown in Wabtec Corporation Parts Catalog
of the locomotive or vehicle on which the Portion is mounted. 3207-6, S.1 .
The SA-26 Independent Brake Valve Portion is most often
used as a component of a 26 Type Brake Valve and is 2.0 OPERATION & ADJUSTMENT
mounted on the 26 Type Brake Pipe Bracket. The SA-26
Independent Brake Valve and the SA-26 Independent Brake 2.1 OPERATION
Valve Portion may be used in equipment arrangements
where air pressure does not exceed 150 psig. The SA-26 Independent Brake Valve, and/or Brake Valve
Portion provides a means for independent control of the
The SA-26 Independent Brake Valve Portion is a small locomotive brake cylinder pressure irrespective of the
capacity, self-lapping, diaphragm operated type regulating automatic brake.
valve which delivers an air supply pressure to an auxiliary
device at a controlled rate. The delivery pressure is The independent brake valve handle has two positions;
determined by a control spring force that is adjustable within namely, Release position at the extreme left end of the
specific limits. The Brake Valve Portion is available with quadrant, and Full Application position at the extreme right
different style handles in several pressure ranges up to 85 end of the quadrant. From Release to Full Application position

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operation & maintenance instruction

is an application zone or sector and the further the handle 2.2 ADJUSTMENT
is moved to the right into this sector, the greater will be the
application pressure available until full application pressure Manual adjustment of delivery pressure is made at the
is obtained at the extreme right end of the handle movement. adjusting screw on the control spring housing. If a higher
Movement of the independent brake valve handle from pressure is desired, the compression on the spring is
Release position towards Full Application position actuates increased so that a higher delivery pressure will be required
a cam which in turn positions a supply and exhaust valve to lap the valve portion. If a lower pressure is desired, the
assembly to first seat the exhaust valve and then unseat the compression on the spring is decreased so that a lower
supply valve. Main reservoir air will then flow past the delivery pressure will be required to lap the valve portion.
unseated supply valve from port No. 30 to port No. 20. Port
No. 20 from the brake valve pipe bracket is connected to a 3.0 MAINTENANCE SCHEDULE
control port at a relay valve.
IMPORTANT: THE SA-26 INDEPENDENT BRAKE VALVE
As air pressure develops in port No. 20, it also develops on PORTION SHOULD BE REMOVED FROM THE VEHICLE,
the inner face of the diaphragm in the independent brake TAKEN TO THE SHOP, THOROUGHLY CLEANED,
valve. The buildup of pressure on the diaphragm is opposed LUBRICATED AND TESTED ACCORDING TO THE
by spring pressure on the opposite side and when the FOLLOWING VEHICLE APPLICATION SCHEDULE OR
pressure and spring pressure become balanced, the valve MORE FREQUENTLY IF SERVICE CONDITIONS SO
assembly will be moved to its lap position in which the supply INDICATE:
valve becomes seated to terminate further flow of main
reservoir air to port No. 20. If, as a result of leakage in the RECOMMENDED FREQUENCY -
No. 20 line, the air pressure should drop, the diaphragm TYPE OF APPLICATION AT LEAST ONCE EVERY
assembly will be moved to again unseat the supply valve
and permit main reservoir air to restore the pressure in port Locomotives 24 Months
No. 20 to the value of the spring setting. This is the self- Passenger (Interstate) 24 Months
lapping pressure maintaining feature of the independent Transit 24 Months
brake valve.
4.0 PARTS CATALOG AND REPLACEMENT
Depression of the independent brake valve handle PARTS INFORMATION
regardless of the position of the independent brake valve
handle, will allow for the flow of main reservoir air into port 4.1 PARTS CATALOG
No. 13. This connection is generally made to the locomotive
control valve, where a function is available to provide for a IMPORTANT: When ordering replacement parts for the SA-
release of the locomotive automatic brake. 26 Independent Brake Valve and/or the SA-26 Independent
Brake Valve Portion, refer to the curreent issue of the
Wabtec Corporation recommends the non-removable handle Wabtec Corporation Parts Catalog 3207-6, S.1.
for the independent brake valve, however, the independent
brake valve is arranged with a feature whereby the handle NOTE: The reference numbers used in this publication
may be removed when it is placed in Release position. and those used in the parts catalog may differ. Check the
descriptive parts name and part number to be sure that the
desired part is ordered.
WARNING: BEFORE PROCEEDING TO REMOVE THE
INDEPENDENT BRAKE VALVE HANDLE, THE AUTOMATIC
4.2 REPLACEMENT PARTS
BRAKE VALVE HANDLE MUST BE PLACED IN FULL
SERVICE POSITION (APPROXIMATELY A 25 PSI BRAKE
IMPORTANT: To obtain satisfactory operation and reliability
PIPE REDUCTION). BRAKE CYLINDER PRESSURE
of the SA-26 Brake Valve and/or the SA-26 Brake Valve
MUST BE APPLIED TO THE LOCOMOTIVE, AND PROPER
Portion, ONLY Wabtec Corporation replacement Parts are
PROCEDURES FOLLOWED FOR CUTTING OUT BRAKE
to be used in the maintenance of these devices.
OPERATION CONTROL ON THIS LOCOMOTIVE. FAILURE
TO COMPLY WITH THESE INSTRUCTIONS MAY RESULT
IN UNINTENTIONAL LOCOMOTIVE MOVEMENT WHICH
COULD POSSIBLY CAUSE EQUIPMENT DAMAGE AND/
OR INJURY TO PERSONNEL.

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operation & maintenance instruction

5.0 SAFETY PROCEDURES & WARNINGS device be allowed to vent before this device and/
or any component part is removed from the
Regular car builder and/or owner-operating property and/ equipment arrangement.
or shop safety procedures MUST BE followed when
performing any work on the SA-26 Brake Valve Portion and/ • Bottled up air under pressure (even though air
or its component parts. supply is cut off) may cause gaskets and/or
particles of dirt to become airborne and an
The work area should be clean. increase in sound level when this device and/or
any component part is removed from the
equipment arrangement. Personal eye and ear
WARNING protection must be worn and care taken to avoid
The following statements of warning apply, all or in part, possible injury when performing any work on this
wherever the symbol appears in the maintenance device and/or component part.
procedures. Failure to observe these precautions may • To prevent receiving electrical shock when
result in serious injury to those performing the work performing electrical tests, hands must be clear
and/or bystanders. of electric components, contacts and housing, and
• The use of an air jet, which must be less than 30 the required "in-lab" grounding procedures must
p.s.i.g., to blow parts clean or to blow them dry be strictly adhered to. A wooden work bench
after being cleaned with a solvent will cause should be used. Failure to heed this WARNING
particles of dirt and/or droplets of the cleaning could result in severe injury or death.
solvent to be airborne. Wire brushing may also • An adequate support or lifting device must be
cause particles of dirt, rust and scale to become available to support the Device and/or Valve
airborne. These conditions may cause skin and/or Portion(s) during removal, installation and
eye irritation. maintenance procedures.
• When using an air jet do not direct it toward
another person. Improper use of air jet could result 6.0 CLEANING SOLVENT AND LUBRICANT
in bodily injury.
6.1 The cleaning solvent used for cleaning reusable parts
• Personal eye protection must be worn when
MUST BE an aliphatic organic solution such as mineral
performing any work on this device or its
spirits or naphtha, that will dissolve oil or grease, and that
component parts to avoid any possible injury to
will permit all parts to be cleaned without abrasion. Cleaning
the eyes.
solvents ARE ONLY to be used in well ventilated areas.
• The use of solvents as cleaning agents and the
use of lubricants can involve health and/or safety
hazards. The manufacturers of the solvents and 6.2 Number 2 Silicone Grease, Wabtec Corporation
lubricants should be contacted for safety data Specification M-7680-2 (Industry Designation MIL-G-4343)
(such as OSHA Form OSHA-20 or its equivalent). such as Dow Corning Corporation Dow Corning 55M, is
The recommended precautions and procedures of required for the lubrication of specified o-rings, o-ring
the manufacturers should be followed. grooves, and the bearing surfaces of the bushings into which
the o-ring assemblies are installed.
• When performing any test or work on devices or
equipment while they are on the vehicle (on-car 7.0 MAINTENANCE PROCEDURES - ON VEHICLE
test etc.) special precautions must be taken to
insure that vehicle movement will not occur which 7.1 PARTS REQUIRED
could result in injury to personnel and/or damage
to equipment. 7.1.1 The repair person will require a NEW or repaired
• Assembly may be under a spring load. Exercise and tested SA-26 Independent Brake Valve Portion, having
caution during disassembly so that no parts spring the same part number as the Portion being replaced, and a
out and cause bodily injury. NEW mounting gasket, Part Number 557237.

• All air supply to this device and/or to any

component part must be cut off and any air in the

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operation & maintenance instruction

7.2 PORTION REMOVAL AND REPLACEMENT 7.2.12 IMPORTANT: Whenever the SA-26 Independent
Brake Valve Portion is removed from an equipment
7.2.1 IMPORTANT: ALL owner-operating property safety arrangement for any reason, and It Is reinstalled or
procedures and the Warnings listed in Section 5.0 of this replaced with a NEW or repaired and tested SA-26
publication are to be followed and adhered to. Independent Brake Valve Portion, a standing vehicle
test MUST BE performed to be sure that the SA-26
7.2.2 The handbrakes of the vehicle are to be applied and Independent Brake Valve Portion and/or the SA-26
the wheels chocked to prevent unintentional movement of Independent Brake Valve function properly in the total
the vehicle. brake equipment arrangement.

7.2.3 ALL air flow to the SA-26 Independent Brake Valve 7.2.13 IMPORTANT: Remove ALL warning placards and
Portion is to be cut-off and ALL trapped air vented. the wheel chocks before aftempting to move the vehicle.

7.2.4 Warnings piacards indicating that work is being 8.0 MAINTENANCE PROCEDURES - IN-SHOP
performed are to be placed on and about the vehicle.
IMPORTANT: When performing the procedures which
7.2.5 IMPORTANT: Provide an adequate support or lifting follow, DO NOT use hard or sharp metal tools to remove o-
device which will hold in excess of twenty-five pounds to rings, gaskets or the diaphragm. Exercise care so that NO
support the Brake Valve Portion. damage is done to metal parts.

7.2.6 Remove the mounting hardware which secures the WARNING: Springs within the assembly may be, or
SA-26 Independent Brake Valve Port’on and its mounting will be under compression. Exercise care so that parts are
gasket to the pipe bracket or laminate. not inadvertently expelled from the assembly. Inadvertently
expelled parts may cause bodily injury and/or damage to
7.2.7 Remove the Brake Valve Portion and mounting gasket equipment.
from the pipe bracket or laminate. SCRAP the gasket.
THE WORK AREA IS TO BE CLEAN.
7.2.8 Inspect the mounting face of the pipe bracket or
laminate to be sure that it is clean. Be sure that the ports
are clean and unrestricted. If necessary, blow the ports 8.1 DISASSEMBLY
clean with a low pressure jet of clean dry air. Exercise
care so that no dirt is blown into the ports. It is not necessary 8.1.1 Remove the handle assembly (27, 28, 29) from
to remove the pipe bracket or laminate unless they are the brake valve portion. This is done by exerting a pulling
damaged. Follow carbuilder and owner-operating property force on the knob (7) on the handle retaining pin assembly
instructions for removal. (4). This frees the handle assembly (27, 28, 29) from its
internal locking feature. The handle assembly (27, 28, 29)
7.2.9 Remove ALL protective materials from the NEW or may then be pulled out from the brake valve body (45), but
repaired and tested SA-26 Independent Brake Valve Portion. only when the handle assembly (27, 28, 29) is in the Release
Be sure that ALL tape is removed from all ports. position.

7.2.10 Install a NEW mounting gasket, Part No. 557237, NOTE: Certain SA-26 Independent Brake Valve Portions
and a NEW or repaired and tested SA-26 Independent Brake are equipped with a handle blocking screw instead of a
Valve Portion on the pipe bracket or laminate and secure handle retaining pin assembly. It will be necessary to remove
them in place by installing the mounting hardware. the blocking screw (4) before the handle assembly can be
removed.
IMPORTANT: If self-locking type hardware is used, IT MUST
BE NEW. 8.1.2 Inspect the roller (29) of the handle assembly. If
there are any signs of flat spots on the roller surfaces, the
7.2.11 Provide adequate protection to prevent dirt and/or roller (29) is to be replaced. Press out the 3/16" x 1/2"
moisture from entering the removed Brake Valve Portion cylindrical spring pin (28) to remove the roller (29).
and transport it to the shop for maintenance. Reassemble in reverse order using a NEW 3/16" x 1/2"
cylindrical spring pin (28).

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operation & maintenance instruction

Portion is equipped, from the quick release valve body (13).

8.1.3 IMPORTANT: Using a 1/2" key size, multispline wrench,
such as the Wabtec Corporation Part No. 517557, release 8.1.14 Remove the spring (9) from the quick release valve
the compression on the adjusting spring (34), which is caged (18) which is located in the valve portion body (45).
in the spring housing (31) by turning the adjusting screw
(32) COUNTERCLOCKWISE as viewed from the adjusting 8.1.15 Remove the quick release valve with o-ring (16,
screw end of the spring housing. DO NOT attempt to 17, 18) as a unit from the valve portion body (45).
disassemble the Brake Valve Portion until all compression
on the adjusting spring is relieved. 8.1.16 Remove and SCRAP the two 15/16" O.D.o-rings (17)
and the 13/16" O.D. o-ring (16) from their grooves on the
NOTE: It is not necessary to entirely remove the adjusting quick release valve (18).
screw (32) from the spring housing (31) unless it is damaged,
but care MUST BE taken to be sure that all spring 8.1.17 Depress and hold the pin (8) in the housing (12),
compression is removed before proceeding with step 8.1.4. then remove the 1/16" x 1/2" cylindrical spring pin (6) from
the end of the pin (8), then slowly release the hold on the
8.1.4 Exercising care so that no parts are inadvertently pin (8) permiftina the force of the spring (11)
expelled from the assembly, slowly and carefully remove to extend the spring (11) its full travel.
the four 1/2" hex nuts (30) which secure the spring housing
(31) to the body (45). 8.1.18 Remove the 3/4" O.D. washer (7) from the end of
the pin (8) and housing (12).
8.1.5 Remove the spring housing (31), diaphragm with valve
seat assembly and o-ring (35 to 39, 40) as a unit from the 8.1.19 Slide the pin (8) from the spring (11) and housing
spring housing (31), then remove the adjusting spring (34) (12) from the threaded end of the housing (12).
and the spring seat (33).
8.1.20 Using the proper tool, remove the retaining ring (9)
8.1.6 Remove and SCRAP the 3/4" O.D. o-ring (40) from from inside the housing (12).
the valve seat (39). Remove the special hex nut (36),
diaphragm follower (37) and diaphragm (38) from the valve 8.1.21 Remove the top 0.360" O.D. washer (10), spring (1
seat (39). SCRAP the special nut (36) and the diaphragm 1) and the lower 0.360" 0. D. washer (10) from the housing
(38). (12).

8.1.7 Remove the exhaust valve spring (41) from the brake 8.1.22 Replace any part that is worn, rusted, broken, or
valve body (45). distorted with NEW Wabtec Corporation parts and
reassemble in reverse order of disassembly.
8.1.8 Remove the inlet valve unit assembly with o-rings (42,
43) from the body (45) as a unit. 8.2. CAM DOG ASSEMBLY

8.1.9 Remove and SCRAP the two 3/4" O.D. o-rings (43) 8.2.1 Wash the cam dog assembly (20 to 23) using the
from their grooves in the inlet valve unit assembly cleaning solvent as described in Section 6.1.
(42).
8.2.2 After the cam dog assembly is cleaned, it MUST BE
8.1.10 Remove the three 3/8" x 1 “ hex head cap screws (1) completely dried. Use a low pressure jet of clean dry air to
which secure the quick release valve body (13) to the brake blow the assembly completely dry.
valve body (45), then remove the quick release valve body
(13). 8.2.3 Inspect the assembly for damage and excessive wear.
If the roller (22) is worn, or if there is any sign of damage,
8.1.11 Remove and SCRAP the body gasket (14). the roller is to be replaced with a NEW Wabtec Corporation
part. Be sure that the pin (21) is free from damage and not
8.1.12 Remove the retaining ring (2) and the spring seat bent. If damaged in any way, the pin (21) is to be replaced
(3) from the quick release valve body (13). with a NEW Wabtec Corporation part.

8.1.13 Remove the handle retaining pin assembly (5) or the 8.2.4 The cam dog assembly can be disassembled as
handle retaining screw (5), depending on how the Valve follows:

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operation & maintenance instruction

45
35 46

40 41 42 43 44
39
38
20 26
30 35
19

17 22 25
32 36 37 23
33 34 21
31 18 20 24
16
(Independent Brake Valve Portion 28
exterior view showing the 15
Pipe Bracket mounting 14
face port locations.) 27
13 29

4
13 20
1
30 10 7
3 12
6
2 8

Approximate net weight: 14 lbs. 5/16-18UNC

5 11 9
Threads

Figure 3 - Exploded View

8.2.6 REMAINING PARTS

8.2.4.1 Remove the 1/16" x 1/2" cotter pins (20) from each
end of the roller pin (21), then remove the roller pin (21) 8.2.6.1 Clean ALL remaining parts by washing them with
and roller (22) from the cam dog (23). SCRAP the cotter the prescribed cleaning solvent as described in Section 6.1.
pins (20). Springs may be wire brushed to assist in cleaning and
removal of any rust.
8.2.4.2 Using the required NEW parts, reassemble the cam
dog assembly in reverse order of disassembly. Use NEW 8.2.6.2 After the parts have been cleaned, they MUST BE
1
/16" x 1/2" cotter pins (20). completely dried. Use a low pressure jet of clean, dry air to
blow the parts dry.
8.2.5 NON-REUSABLE PARTS
8.2.6.3 Inspect the parts. Bushings in the bodies MUST
8.2.5.1 ALL o-rings, gaskets, the diaphragm and the special BE free of nicks and scratches and free of worn areas.
nut are to be SCRAPPED and replaced with NEW Wabtec
Corporation parts.

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operation & maintenance instruction

Springs are to be replaced if they are rusted, pitted, distorted, 8.4 ASSEMBLY
bent, broken, damaged in any way, or if the spring has
taken a permanent set. NOTE: The following Rubber Parts Kits are available:
For Overhaul Maintenance - Part No. 559549;
Retaining rings MUST BE elastic enough to hold securely. For Moving Parts - Part No. 559550.
Retaining rings MUST snap into their grooves when installed.
8.4.1 Install the thimble (44) into the inlet valve unit assembly
ALL remaining parts MUST BE free of damage. Replace passage on the inside of the brake valve portion body (45).
ANY part that is bent, broken, cut, shows signs of excessive The thimble (44) is to be installed with the open end toward
wear, damaged in any way, or that is in such a condition the inlet valve bushing of the body (45).
that may result in the unsatisfactory operation of the SA-26
Independent Brake Valve Portion or the SA-26 Independent
8.4.2 Install the quick release valve seat (3) in the release
Brake Valve.
valve body (13) and secure it in place by installing the
8.2.6.4 Remove the cam dog pin (19) from the valve portion retaining ring (2). The retaining ring (2) MUST snap into its
body (45). groove in the body (13).

8.2.6.5 Remove the cam dog sub-assembly (21 to 23) as a 8.4.3 Apply a light coating of Number 2 Silicone Grease,
unit from the valve portion body (45). Wabtec Corporation Specification M-7680-2, to the surface
of two NEW 15/16" O.D. o-rings (17) and a NEW 13/16" O. D.
8.2.6.6 Remove the cam with pusher pin sub-assembly (24 o-ring (16). Also fill the o-ring grooves of the quick release
to 26) as a unit from the valve portion body (45). valve (18) and lightly lubricate the bearing surfaces of the
quick release valve bushing of the quick release valve body
8.2.6.7 Using the proper tool, remove the 1/4" x I" cylindrical (13) with the lubricant.
spring pin (25) which secures the pusher pin (24) in place
in the cam (26), then remove the pusher pin (24). 8.4.4 Install the two NEW lubricated 15/16" O.D. o-rings
(17) and the NEW 13/16" O. D. o-ring (16) in their
8.2.6.8 Remove the thimble (44) from the inlet valve unit grooves on the quick release valve (18).
cavity inside of the valve portion body (45).
8.4.5 Install the spring (1 5) into the bottom end of the
8.2.6.9 If the mounting gasket is stli on the mounting face quick release valve (18), the end near the 13/16" O. D. o-
of the valve portion (45), it is to be removed and SCRAPPED. ring, then install the spring - quick release valve subassembly
This gasket IS NOT a part of the SA-26 Brake Valve Portion. (15 to 19) into the bushing in the quick release valve body
(13).
8.3 CLEANING AND INSPECTING
8.4.6 Assemble the push pin (24) into the cam (26) and
IMPORTANT: Cleaning solvents ARE ONLY to be used in
secure it in place by installing the 1/4" x 1" cylindrical spring
well ventilated areas.
pin (25).
8.3.1 HANDLE RETAINING PIN ASSEMBLY
8.3.7 Install the cam with push pin sub-assembly (24 to 26)
8.3.1.1 Wash the handle retaining pin assembly (5) using in place in the brake valve portion body (45).
the cleaning solvent as described in Section 6.1.
8.4.8 Assemble the cam dog with roller sub-assembly (20
8.3.1.2 After the handle retaining pin assembly has been to 23) into the brake valve portion body (45) and secure it in
cleaned, it MUST BE completely dried. Use a low pressure place by installing the cam dog pin (13). The small diameter
jet of clean dry air to blow the assembly dry. end of the pin (13) is to be used to secure the cam dog
sub-assembly (20 to 23) in place. Align the roller (22) of
8.3.1.3 Inspect the assembly for excessive wear at the end the cam dog sub-assembly so it contacts the cam (20).
of the pin (8) and for a broken spring (11). If necessary,
disassemble the handle retaining pin assembly (5) and IMPORTANT: NO LUBRICANT is to be used on the cam or
replace the broken or worn parts as follows: the cam dog roller. The surface of the roller and cam MUST
BE kept clean and dry to retain the required rolling friction
8.3.1.3.1 Remove the 5/16" lock washer (7) from the handle between these two contacting surfaces.
retaining pin assembly (5).

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operation & maintenance instruction

8.4.9 Place a NEW body gasket (14) in position on the end of the bore of the valve seat (39). Be sure that the
brake valve portion body (45). bead of the diaphragm (38) is positioned in the bead groove
of the brake valve body (45).
8.4.10 With the spring and quick release valve
subassembly (15 to 18) properly positioned in the bushing 8.4.20 Install the adjusting spring (34) over the special nut
of the quick release valve body (13), carefully align the (36) so that the spring (34) seats on the diaphragm follower
quick release valve body (13) on the brake valve portion (37).
body (45) and gasket (14).
8.4.21 Install the spring seat (24) so that the small diameter
8.4.11 Secure the quick release valve body (13) to the end of the seat (24) fits into the end of the spring (34).
brake valve portion body (45) by installing three 3/8" x 1“
hex head cap screws (1). Equally tighten the screws (1). 8.4.22 Place the spring housing - adjusting screw
subassembly (31, 32) over the adjusting spring (34) and
8.4.12 Install a NEW diaphragm (38) and the diaphragm spring seat (33). If the housing (31) has a vent, it should be
follower (37) on the valve seat (39) and secure them in positioned toward the pipe bracket mounting face. Align
place by installing a NEW special hex nut (36). Snug the the holes of the housing (31) with the studs (46) of the
nut (36) against the diaphragm follower (37). brake valve portion body (45).

8.4.13 Apply a light coating of Number 2 Silicone Grease, 8.4.23 Secure the spring housing (31) in place by installing
Wabtec Corporation Specification M-7680-2, to the the four 5/16" hex nuts (30) on the studs (46) of the brake
surfaces of a NEW 3/4" O.D. o-ring (40). Also fill the o- valve portion body (45). Equally tighten the nuts (30).
ring groove of the valve seat (39) with the lubricant.
IMPORTANT: DO NOT tighten the adjusting screw (32)
8.4.14 Install the NEW lubricated 3/4" O.D. o-ring (40) into at this time. The adjusting screw will be set during the Testing
its groove on the valve seat (39). Remove any excess of the SA-26 Independent Brake Valve Portion.
lubricant by wiping with a clean, dry, lint-free cloth.
8.4.24 Install the handle retaining pin assembly (4), if the
8.4.15 Apply a light coating of Number 2 Silicone Grease, Portion is so equipped, into its threaded hole in the bottom
Wabtec Corporation Specification M-7680-2, to the of the quick release valve body (13).
surfaces of two NEW 3/4" O.D. o-rings (43). Also fill the
o-ring grooves of the inlet valve unft assembly (42) and 8.4.25 Position the cam (26) in the “Release” position, then
lightly lubricate the bearing surfaces of the bushing of the insert the handle (26, 27, 28) into the slot in the cam (26).
brake valve portion body (45) with the lubricant.
8.4.26 Pull back and hold the knob washer (7) of the handle
8.4.16 lnstall the two NEW lubricated 3/4" O.D. o-rings retaining pin assembly (5) in order to permit the handle
(43) in their grooves on the inlet valve unit assembly (42). assembly (27, 28, 29) to move its full travel into the cam
Remove any excess lubricant by wiping with a clean, dry, (26).
lint-free cloth.
8.4.27 Release the hold on the knob washer (7) to lock
8.4.17 Insert the inlet valve unit assembly with o-rings the handle assembly (27, 28, 29) in place.
(42, 43) into the brake valve body portion (45) with the
hardened pin end of the assembly (42), entering the open 8.4.28 NOTE: If the Portion is equipped with a handle
end of the thimble (44) which was previously installed in blocking screw instead of a handle - retaining pin assembly,
the body (45). The dumbbell end of the unit assembly it should be installed at this time.
(42) is to be facing outward from the brake valve body
portion (45). 9.0 TESTING AND ADDITIONAL INFORMATION

8.4.18 Install the spring (41) over the dumbbell end of the 9.1 IMPORTANT: After the SA-26 Independent Brake
inlet valve unit assembly (42). Valve Portion has been fully assembled, but before it is
returned to service, IT MUST pass a series of tests
8.4.19 Place the diaphragm - exhaust valve seat following the procedures of the current issue of the
subassembly with o-ring (35 to 40) in position in the brake Wabtec Corporation Test Specification T-2403-0.
valve body (45) so that the spring (41) is positioned in the

July, 1991 Page 9 of 10

4207-6, S.1

operation & maintenance instruction

NOTE: Test Specification T-2403-0 covers the following SA- gasket, Part No. 557237, MUST BE used. This gasket
26 Independent Brake Valve Portions: IS NOT a part of the SA-26 Independent Brake Valve
Part No’s. 558497, 559454, 563981, 564011, 564316, Portion.
576233, 576258, 582398, 583393, 586088, 592171,
592528, and 592529. 9.3 IMPORTANT: Whenever the SA-26 Independent
Brake Valve Portion is removed from an equipment
9.1.1 The Test Specification may be obtained by contacting arrangement for any reason, and It Is reinstalled or
your Wabtec Corporation Representative. If the SA-26 replaced with a NEW or repaired and tested SA-26
Independent Brake Valve Portion IS NOT listed in Paragraph Independent Brake Valve Portion, a stationary vehicle
9.1, contact your Representative for the current Test test MUST BE made to be sure that the SA-26
Specification covering that specific part number. Independent Brake Valve Portion and/or the SA-26
Independent Brake Valve functions properly in the total
9.2 IMPORTANT: Whenever the SA-26 Independent equipment arrangement.
Brake Valve Portion is removed from an equipment
arrangement for any reason, and it is reinstalled or
replaced with a NEW or repaired and tested SA-26 Consult your Wabtec Corporation Representative if additional
Independent Brake Valve Portion, a NEW mounting information is required.

WABCO Locomotive Products

1001 Air Brake Avenue • Wilmerding, PA 15148
(412) 825-1000 • Fax (412) 825-1019
www.wabtec.com

Page 10 of 10 July, 1991