Bendix Commercial Vehicle Systems BENDIX 720CC COMPRESSOR - Manual (Page 8)

8
INLET & DISCHARGE VALVES
In order to test the inlet and discharge valves, it is necessary
to have shop air pressure and an assortment of fittings. A
soap solution is also required.
1. With the engine shut off, drain ALL air pressure from the
vehicle.
2. Disconnect the inlet and discharge lines.
3. Apply 120-130 psi shop air pressure to the discharge port
and then apply and release air pressure to the inlet port.
Soap the inlet port and note that leakage at the inlet port
does not exceed 200 sccm.
If excessive leakage is noted in Test 3, replace or repair
the compressor using genuine Bendix ® replacements or
maintenance kits available from any authorized Bendix parts
outlet.
While it is possible to test for inlet and discharge leakage, it
may not be practical to do so. Inlet and discharge valve leakage
can generally be detected by longer compressor build-up and
recovery times. Compare current compressor build-up times
with the last several recorded times. Make certain to test for
air system leakage, as described under “In-Service Operating
Tests”, before making a determination that performance has
been lost.
COMPRESSOR REMOVAL & DISASSEMBLY
GENERAL
The following disassembly and assembly procedure is
presented for reference purposes and pre-supposes that
a rebuild or repair of the compressor is being undertaken.
Several maintenance kits are available and the instructions
provided with these parts and kits should be followed in lieu
of the instructions presented here.
MAINTENANCE KITS & SERVICE PARTS
BENDIX
® 720
CC
TWIN CYLINDER COMPRESSOR
Compressor Seal Kit (Major) . . . . . . . . . . .K026808
Compressor Seal Kit (Minor) . . . . . . . . . . .K051352
Discharge Safety Valve Kit . . . . . . . . . . . .K026809
Compressor to Engine
Supplied by the
Mounting Face Sealant . . . . . . . engine manufacturer
REMOVAL
In many instances it may not be necessary to remove the
compressor from the vehicle when installing the various
maintenance kits and service parts. The maintenance
technician must assess the installation and determine the
correct course of action. These instructions are general
and are intended to be a guide. In some cases additional
preparations and precautions are necessary. In all cases follow
the instructions contained in the vehicle maintenance
manual in lieu of the instructions, precautions and
procedures presented in this manual.
1. Block the wheels of the vehicle and drain the air
pressure from all the reservoirs in the system.
2. Drain the engine cooling system and the cylinder
head of the compressor. Identify and disconnect all
air, water and oil lines leading to the compressor.
3. Remove as much road dirt and grease from the
exterior of the compressor as possible.
4. Remove the discharge fitting, if applicable, and note
their position on the compressor to aid in reassembly.
5. Remove any supporting bracketing attached to
the compressor and note their positions on the
compressor to aid in reassembly.
6. Remove the six mounting bolts that retain the
compressor to the side of the engine block. Note
the position of the six mounting bolts. Two of the six
bolts are shorter and must be installed in their original
locations. Remove the compressor from the vehicle.
7. Inspect drive gear and associated drive parts for
visible wear or damage. If the compressor drive
gear is worn or damaged, the compressor must be
replaced. Refer to the engine manufacturer's service
manual to address the associated engine drive parts.
8. If the compressor is being replaced, stop here and
proceed to “Installing the Compressor” at the end
of the assembly procedure. ( Note: Replacement
compressors come with the drive gear pre-
assembled on the compressor.)
PREPARATION FOR DISASSEMBLY
Place a clean rag over the openings that expose the
gear and crankshaft / connecting rod assembly. Refer
to Figure 3. No contamination is permitted in these
areas.
Remove the balance of road dirt and grease from the
exterior of the compressor with a cleaning solvent. If the
rear end cover is being removed from the compressor,
mark it, along with the two cap screws, in relation to
the crankcase. It is also recommended to mark the
relationship of the cylinder head, cooling plate, valve
plate assembly and crankcase.
A convenient method to indicate the above relationships
is to use a metal scribe to mark the parts with numbers or
lines. Do not use marking methods, such as chalk, that
can be wiped off or obliterated during rebuilding.
Prior to disassembly make certain that the appropriate
kits are available. Refer to Figure 8 during the entire
disassembly and assembly procedure. The serviceable
items are identified by "Item" numbers 1 through 11.