WABCO System Saver 318 User manual

NON-THROUGH DRIVE THROUGH DRIVE
SYSTEM SAVER 318 AIR
COMPRESSOR FOR MACK
E-TECH™ AND ASET™
ENGINES
MAINTENANCE MANUAL

Service Notes
Information contained in this publication was in effect at the time the publication
was approved for printing and is subject to change without notice or liability.
WABCO reserves the right to revise the information presented or to discontinue the
production of parts described at any time.
WABCO Maintenance Manual 31 (Revised 08-18)
About This Manual
This manual provides service and repair procedures for the WABCO
System Saver 318 air compressor.
Before You Begin
1. Read and understand all instructions and procedures before
you begin to service components.
2. Read and observe all Warning and Caution hazard alert
messages in this publication. They provide information that can
help prevent serious personal injury, damage to components,
or both.
3. Follow your company’s maintenance and service, installation,
and diagnostics guidelines.
4. Use special tools when required to help avoid serious personal
injury and damage to components.
Hazard Alert Messages and Torque
Symbols
WARNING
A Warning alerts you to an instruction or procedure that you
must follow exactly to avoid serious personal injury and
damage to components.
CAUTION
A Caution alerts you to an instruction or procedure that you
must follow exactly to avoid damage to components.
@This symbol alerts you to tighten fasteners to a specified torque
value.
How to Obtain Additional Maintenance
and Service Information
Visit Literature on Demand at meritor.com. WABCO publications are
also available on our website: wabco-na.com.
WABCO Customer Care
Call WABCO North America Customer Care at 855-228-3203.
How to Obtain Tools and Supplies
Specified in This Manual
Call Meritor’s Commercial Vehicle Aftermarket at 888-725-9355 to
obtain tools and supplies.

Contents
pg. 1 Section 1: Introduction
Application
Description
2Operation
Maintenance Intervals
Cylinder Head
3 Visual Inspection
4Section 2: Troubleshooting
7Section 3: Compressor Replacement
Compressor
Replacement Information
Removal
8 Installation
Cylinder Head
Removal
9 Installation
10 Testing
Air System Leakage Test

Notes

1 Introduction
1
WABCO Maintenance Manual 31 (Revised 08-18)
1 Introduction
Application
앫System Saver 318 non-through drive version air compressor
used on Mack engines. Figure 1.1.
앫System Saver 318 through-drive version air compressor used on
Mack engines. This unit is required to run hydraulic power
steering pumps. Figure 1.1.
앫Swept volume displacement: 18.7 cubic feet per minute.
앫Flange mounted to the engine.
— Coupling driven.
— Inlet air, oil lubrication and coolant supplied from the engine.
앫Pneumatic pressure signal from the governor controls
compression:
— Integrated pressure relief valve protects the compressor
and engine if discharge or governor lines become blocked,
or if compressor cannot unload. The valve prevents the
compressor from pumping above 250 psi in the event of
a blocked discharge line or other malfunction.
Figure 1.1
Description
The WABCO System Saver 318 air compressor provides and
maintains air under pressure to operate devices in the air brake and
auxiliary air systems of a vehicle. It consists of two major
subassemblies: Cylinder head and crankcase/cylinder block.
Figure 1.2.
Figure 1.2
The cylinder head contains the inlet, discharge and unloader
valving, as well as an integral relief valve. There are two water ports,
marked Port 9, an air discharge port, marked Port 2, and an inlet
port, marked Port 0. The cylinder head is mounted on the
crankcase/cylinder block.
The crankcase/cylinder block contains the cylinder bore, piston,
bearings, crankshaft, governor port and connecting rod.
Figure 1.1
1003372b
NON-THROUGH DRIVE THROUGH DRIVE
Figure 1.2
NON-THROUGH DRIVE THROUGH DRIVE
1003373b
CYLINDER
HEAD
CRANKCASE
(CYLINDER BLOCK)
CYLINDER
HEAD
CRANKCASE
(CYLINDER BLOCK)

1 Introduction
2WABCO Maintenance Manual 31 (Revised 08-18)
Operation
The compressor is driven by the engine and its crankshaft turns
continuously while the engine is running. Compression of air is
controlled by the governor and by the compressor’s unloading
mechanism.
The governor maintains the brake system air pressure at preset
maximum and minimum levels. The governor is mounted apart from
the compressor, either horizontally or vertically. The governor port is
located on the crankcase of the compressor. Figure 1.3.
Figure 1.3
The unloader mechanism controls the air compression cycle; an
air compression cycle has three phases:
1. Induction: Air flows from the engine to the compressor,
opening an inlet valve in the cylinder head of the compressor.
2. Compression: Air pressure is increased, causing the
compressor’s discharge valve to open.
3. Unloading: Air passes from the cylinder to the inlet chamber of
the cylinder head via a port controlled by a sliding leaf valve.
When system cut-in pressure is reached, air is exhausted from
the unloader port.
4. After unloading, the unloader piston returns the sliding leaf
valve to the loaded position. This seals the unloader ports and
compression resumes. Figure 1.4.
Figure 1.4
Maintenance Intervals
The WABCO System Saver 318 air compressor receives inlet air, oil
and coolant from the engine, so it is important to follow the engine
manufacturer’s recommendations and maintenance schedules
regarding fluid levels, air filter and recommended change intervals.
Cylinder Head
Remove carbon deposits from the discharge cavity and rust and
scale from the cooling passages of the cylinder head.
Clean carbon and dirt from the inlet and unloader passages.
NOTE: Shop air may be used to blow the carbon and dirt deposits
from the unloader passages.
Figure 1.3
GOVERNOR
PORT
1003374b
Figure 1.4
1003375b
SLIDING LEAF
VALVE

1 Introduction
3
WABCO Maintenance Manual 31 (Revised 08-18)
Visual Inspection
A visual check of the compressor can detect minor problems. This check should be part of the vehicle preventive maintenance program.
Figure 1.5.
Figure 1.5
Figure 1.5
1003376b
Check air inlet and
discharge ports
between compressor
and governor.
Check
under plate
or at power
steering
pump for
leakage.
Check water ports
for leakage.
Check
flanges
for cracks
or breaks.
Check air inlet and
discharge ports
between compressor
and governor.
NON-THROUGH DRIVE THROUGH DRIVE
Check
flanges
for cracks
or breaks.

2 Troubleshooting
4WABCO Maintenance Manual 31 (Revised 08-18)
2 Troubleshooting
Hazard Alert Messages
Read and observe all Warning and Caution hazard alert messages in this publication. They provide information that can help prevent serious
personal injury, damage to components, or both.
WARNING
To prevent serious eye injury, always wear safe eye protection when you perform vehicle maintenance or service.
Use Table A to troubleshoot the WABCO System Saver 318 air compressor.
NOTE: If you have any questions or need additional information, please contact WABCO North America Customer Care at 855-228-3203.
Table A: Compressor Troubleshooting Guide
Condition Possible Cause Solution
Compressor passes
excessive oil (for example,
the presence of oil at
exhaust air brake system
valves, oil in air dryer
desiccant, etc.)
Blocked or restricted oil return Clean oil drain passages in the compressor and on the engine
surface. Verify correct passage alignment.
Contaminated inlet air or oil Replace damaged, defective or dirty engine air filter.
Repair any leaking, damaged or defective compressor air intake
components.
Change engine lubricating oil.
NOTE: To avoid this condition, make sure vehicle manufacturer’s oil
and filter maintenance schedules are followed.
Restricted air inlet or excessive
vacuum present at compressor inlet
Verify engine or compressor air cleaner is functioning correctly.
Replace if necessary.
Repair compressor air inlet kinks or excessive bends.
Check vehicle specifications to ensure air and coolant lines meet all
requirements.
Excessive engine crankcase pressure Verify engine crankcase venting is to manufacturer’s specification.
Compressor duty cycle too high Check system for leaks. Make necessary repairs.
None of the above, but condition
persists
Replace the compressor.
Compressor leaks oil Physical damage or internal problems
with compressor
Replace the compressor.
Compressor continuously
cycles
Compressor unloader piston leaking With compressor unloaded, check for air leakage. If leaking, replace
the cylinder head.
Governor air leak Refer to the manufacturer’s manual for governor maintenance and
troubleshooting procedures.
Dryer purge valve air leakage Check for air dryer malfunction. Refer to air dryer manufacturer’s
service instructions.
Air leak at governor-compressor
attachment
Inspect connection for physical damage. Inspect and repair
connection.
Air leak at alcohol injector Clear line of any obstructions.
Inspect and repair connection.
Excessive reservoir contamination Drain reservoirs.
None of the above, but condition
persists
Replace the compressor.

2 Troubleshooting
5
WABCO Maintenance Manual 31 (Revised 08-18)
No air delivery
Low air delivery
Low air pressure
Discharge line blockage Check for freeze up in the discharge line.
Check low spots and eliminate any traps in the discharge line.
Inspect and repair compressor discharge port and clear any line
restrictions. Replace damaged lines as necessary.
Check for carbon build-up. If carbon has built up, make sure cooling
lines are not kinked or restricted. If carbon has built up in the
discharge line, replace the line.
Inlet line kinked or restricted Inspect the compressor air induction line for kinks and restrictions.
Repair or replace as necessary.
Governor malfunction or
misadjustment
Check for correct loader/unloader cycles of compressor.
Refer to vehicle manufacturer’s manual for governor maintenance and
troubleshooting procedures.
External contamination Replace broken, defective or dirty air filters. Clean contaminants from
surface of compressor.
Air dryer purge valve stuck open or
leaking
Check for air dryer malfunction. Refer to air dryer manufacturer’s
service instructions.
Chafed or worn discharge line Replace faulty sections of discharge line.
Loose or leaking air line connections Verify all connections are secure.
Tighten to vehicle specifications where necessary.
Inspect port threads for damage. If damage is extensive, replace
cylinder head.
Damage to compressor valves and/or
valve seats
Replace the cylinder head.
Leaking or malfunctioning internal
pressure relief valve
Replace the cylinder head.
Noisy air compressor Loose drive hub
Loose accessory drive coupling
Check fit of drive coupling.
Ensure hub is completely seated and crankshaft nut is tight.
Inspect crankshaft for damage — replace compressor if crankshaft is
damaged.
None of the above, but condition
persists
Replace the compressor.
Broken connecting rod or
crankshaft
Oil starvation to crank pin or front main
bearing
Check oil pressure. Verify oil passage is free of obstructions. Make
necessary repairs.
Failed power steering pump
(through-drive version only)
Verify power steering pump is in correct operating order. Refer to the
component manufacturer’s service instructions.
All of the above Replace compressor.
Condition Possible Cause Solution
Table A: Compressor Troubleshooting Guide

2 Troubleshooting
6WABCO Maintenance Manual 31 (Revised 08-18)
Compressor leaks engine
coolant
Loose fitting Check fittings at compressor and engine for leaks and verify fittings
are correctly torqued.
Cracked coolant port Replace cylinder head.
Porosity in cylinder head Replace cylinder head.
Leaking of gasket internal to the
cylinder head
Verify cylinder head bolts are correctly torqued. Make necessary
adjustments.
Inspect gasket for cracks or signs of wear. Replace if necessary.
Replace cylinder head.
None of the above, but condition
persists
Replace compressor.
Compressor pressurizes
coolant system or coolant
leakage to compressor
inlet
Leaking of gasket internal to the
cylinder head
Inspect gasket. Replace if necessary.
Cavitation or corrosion in cylinder
head
Replace cylinder head.
Porosity in cylinder head or cylinder
head cracked
Replace cylinder head.
None of above, but condition persists Replace the compressor.
Unloader leakage Possible internal damage, including
worn or damaged unloader piston
O-ring, porosity in unloader piston
bore, loose or leaking seal at unloader
piston bore
Replace compressor cylinder head assembly.
Compressor head gasket
failure
Discharge line blocked due to freezing
or carbon build-up
Check for trap (low spots) in lines.
Make necessary repairs.
Clear discharge line. Replace line if necessary.
Check for carbon build-up. If carbon build-up is present, replace the
discharge line.
Frozen or blocked line to governor Clear blocked line. Replace line if necessary.
Check for air dryer malfunction. Repair or replace as required. Refer
to the air dryer manufacturer’s maintenance manual for service
information.
Governor malfunction Repair or replace the governor. Refer to governor manufacturer’s
maintenance manual for service information.
Incorrect cylinder head bolt torque,
machining defect on cylinder head or
block, defective cylinder head gasket
Inspect gasket. Replace if necessary. Verify all bolts are correctly
torqued. If problem persists, replace cylinder head.
None of the above, but condition
persists
Replace compressor cylinder head assembly.
Condition Possible Cause Solution
Table A: Compressor Troubleshooting Guide