Bendix Commercial Vehicle Systems BX2150 AIR COMP (BW1424) - Manual (Page 7)

7
COMPRESSOR COOLING
Every six months, 1800 operating hours or 50,000 miles,
whichever occurs first, inspect the compressor discharge
port, inlet cavity and discharge line for evidence of restrictions
and carboning. If excessive buildup is noted, thoroughly clean
or replace the affected parts and closely inspect the
compressor cooling system. Check all compressor coolant
lines for kinks and restrictions to flow. Minimum coolant
line size is 3/8" I.D. Check coolant lines for internal clogging
from rust scale. If coolant lines appear suspicious, check
the coolant flow and compare to the tabulated technical data
present in the back of this manual.
Inspect and clean the external air cooling fins on the cylinder
portion of the crankcase. If fins are cracked or broken, replace
the compressor.
Inspect the air induction system for restrictions.
LUBRICATION
Every six months, 1800 operating hours or 50,000 miles,
whichever occurs first; check external oil supply and return
lines, if applicable, for kinks, bends, or restrictions to flow.
Supply lines must be a minimum of 3/16" I.D. and return
lines must be a minimum of 1/2" I.D. Oil return lines should
slope as sharply as possible back to the engine crankcase
and should have as few fittings and bends as possible. Refer
to the tabulated technical data in the back of this manual for
oil pressure minimum valves.
Check the exterior of the compressor for the presence of oil
seepage and refer to the TROUBLESHOOTING section for
appropriate tests and corrective action.
OIL PASSING
All reciprocating compressors currently manufactured will
pass a minimal amount of oil. Air dryers will remove the
majority of oil prior to entrance into the air brake system.
For particularly oil sensitive systems the Bendix
® PuraGuard ®
QC ™ oil coalescing filter can be used in conjunction with a
Bendix air dryer.
If compressor oil passing is suspected, refer to the
TROUBLESHOOTING section and TABLE A for the
symptoms and corrective action to be taken. In addition,
Bendix has developed the "Bendix Air System Inspection
Cup" or BASIC test to help substantiate suspected excessive
oil passing. The steps to be followed when using the BASIC
test are presented in APPENDIX A at the end of the
TROUBLESHOOTING section.
COMPRESSOR DRIVE
Every six months, 1800 operating hours or 50,000 miles,
whichever occurs first, check for noisy compressor operation.
Variations in noise level in conjunction with the compression
and unloaded cycles generally indicate loose or worn drive
components.
On belt drive compressors check for pulley and belt
alignment and tension. Adjust as necessary, paying particular
attention not to overtighten belt tension. Check for loose
and out of aligned pulleys. Adjust or replace as necessary.
Compressor crankshaft keyway damage indicates a loose
pulley and often requires compressor replacement. Main
bearing failures on belt driven compressors often indicate
excessive belt tension.
A thorough inspection, and possible replacement, of drive
components should be made at each compressor change.
Special attention should be given to drive gears and couplings
on compressors which have been operated at high discharge
pressures due to a blocked or frozen discharge line.
Check all compressor mounting bolts and retighten evenly
as necessary. Check the condition of all compressor
mounting bracketry, tighten hardware as necessary, and
replace if damaged.
OPERATIONAL TESTS
Every three months, 900 operating hours or 25,000 miles
whichever occurs first. Vehicles manufactured after the
effective date of FMVSS 121, with the minimum required
reservoir volume, must have a compressor capable of raising
air system pressure from 85-100 p.s.i. in 25 seconds or
less. This test is performed with the engine operating at
maximum governed speed. The vehicle manufacturer must
certify this performance on new vehicles with appropriate
allowances for air systems with greater than the minimum
required reservoir volume.
Check unloader operation by building system pressure to
governor cut-out and note that air compression stops. Reduce
system pressure to governor cut-in and note that air
compression resumes. If the compressor fails to respond
as described, make certain the governor is functioning
properly before repairing or replacing the compressor.
COMPRESSOR AIR LEAKAGE TESTS
Compressor leakage tests need not be performed on a regular
basis. These tests should be performed when; it is suspected
that discharge valve leakage is substantially affecting
compressor build-up performance, or when it is suspected
that the compressor is “cycling” between the load and
unloaded modes due to unloader piston leakage.
These tests must be performed with vehicle parked on a
level surface, the engine not running, the entire air system
completely drained to 0 P.S.I., and the inlet check valve
detail parts removed, if applicable.
UNLOADER PISTON LEAKAGE
Remove the governor and apply shop air pressure to the
1/8" pipe thread unloader port on the governor mounting
pad. Listen for the escape of air at the inlet cavity. An audible
escape of air should not be detected. If any question exists