TRW TA S40 Series User manual

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TRW TAS STEERING GEAR
TRW Automotive
Commercial Steering Systems
TAS Steering Gear
Service Manual
T A S40,55,65, 66 AND 85 SERIES

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Hazard Warning Definitions
A warning describes hazards or unsafe practices which could result in
severe personal injury or death.
A caution describes hazards or unsafe practices which could result in
personal injury or product or property damage.
A note gives key information to make following a procedure easier or quicker.
Disclaimer
This Service Manual has been prepared by TRW Commercial Steering Systems for reference and use
by mechanics who have been trained to repair and service steering components and systems on heavy
commercial vehicles. TRW Commercial Steering Systems has exercised reasonable care and diligence to
present accurate, clear and complete information and instructions regarding the TRW Commercial Steer-
ing TAS Series Integral Power Steering Gears. Since this is a general Service Manual, the photographs
and illustrations may not look exactly like the steering gear being serviced. The procedures, therefore ,
must be carefully read and understood before servicing.
If inspection or testing reveals evidence of abnormal wear or damage to the TAS steering gear or if you
encounter circumstances not covered in the Manual, Stop - Consult the vehicle manufacturer's
Service Manual and warranty. Do not try to repair or service a TAS steering gear which has
been damaged or includes any part that shows excessive wear unless the damaged and worn
parts are replaced with original TRW replacement and service parts and the unit is restored to
TRW's specifications for the TAS steering gear.
It is the responsibility of the mechanic performing the maintenance, repairs or service on a particular TAS
steering gear to (a) inspect the steering gear for abnormal wear and damage, (b) choose a repair proce-
dure which will not endanger his/her safety, the safety of others, the vehicle, or the safe operation of
the vehicle, and (c) fully inspect and test the TAS steering gear and the vehicle steering system to ensure
that the repair or service of the steering gear has been properly performed and that the steering gear and
system will function properly.
Patents
TRW Commercial Steering Division TAS power steering gears are covered by several United States and
foreign patents, either issued or pending.
© TRW Inc., 2007

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Contents
Section 1 General Information
Introduction ..............................................................................................................5
Oil Flow Illustration..................................................................................................7
General Design.........................................................................................................8
General Operation....................................................................................................9
Gear Specification Numbers ..................................................................................10
Torque Chart...........................................................................................................11
Exploded View........................................................................................................12
Exploded View Part Descriptions...........................................................................13
Service Parts List....................................................................................................14
Parts Vary by Specification.....................................................................................15
Service Kits ............................................................................................................16
Section 2 Installation
Initial Installation ...................................................................................................18
Initial Poppet Setting .............................................................................................18
Maintenance Tips...................................................................................................19
Output Shaft Grease Pack Diagrams .....................................................................20
Section 3 Gear Disassembly, Inspection and Assembly
Disassembly Preparation .......................................................................................23
Disassembly Procedures ........................................................................................24
Inspection...............................................................................................................31
Assembly Preparation ............................................................................................33
Assembly Procedures.............................................................................................33
Internal Component Repair Procedures
Poppets........................................................................................................41
Valve Housing/Worm Screw ......................................................................43
Roller Bearing - Standard Gears .................................................................50
Roller Bearing - Step Bore Gears ................................................................51
Port Plugs, Screws and Manual Bleed Screw Replacement .................................52
Final Adjustments ..................................................................................................53
Section 4 Reinstallation
Reinstallation Procedure........................................................................................57
Poppet Resetting Procedure...................................................................................57
Glossary.................................................................................................................. 58
All steering mechanisms are safety critical items. As such, it is
imperative that the instructions in this booklet be followed to the letter.
Failure to observe the procedures set forth in this manual may result in a loss of steering.

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Section 1 General Information
Introduction ................................................................................................ 5
Oil Flow Illustration .................................................................................... 7
General Design........................................................................................... 8
General Operation ...................................................................................... 9
Gear Specification Numbers .................................................................... 10
Torque Chart ............................................................................................. 11
Exploded View .......................................................................................... 12
Exploded View Part Descriptions ............................................................. 13
Service Parts List...................................................................................... 14
Parts Vary by Specification....................................................................... 15
Service Kits (General)............................................................................... 16
Service Kits (Gear Specific) ...................................................................... 16

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