Bendix Commercial Vehicle Systems BA-922 COMPRESSOR - Manual (Page 20)

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Symptom: What it may indicate: What you should do:
(g) Restricted air inlet (not enough air
to compressor).
 Check compressor air inlet line for restric-
tions, brittleness, soft or sagging hose con-
ditions etc. Repair as necessary. Refer to
vehicle manufacturer’s guidelines for inlet
line size.
 Check the engine air filter and service if
necessary (if possible, check the air filter
usage indicator).
(i) Compressor malfunction.  Replace the compressor only after making
certain that none of the preceding conditions,
9.0 (a) through 9.0 (h), exist.
(h) Poorly filtered inlet air (poor air
quality to compressor).
 Check for leaking, damaged or defective
compressor air inlet components (e.g.
induction line, fittings, gaskets, filter bodies,
etc.). Repair inlet components as needed.
Note: Dirt ingestion will damage compressor
and is not covered under warranty.
9.0 Air brake
charging system
seems slow to
build pressure.
(continued)
(f) Restricted discharge line.  If discharge line is restricted:
 By more than 1/16" carbon build up,
replace the discharge line (see Table A,
column 2, on page 13 for recommended
size) and go to Test 3 on page 24.
 By other restrictions (e.g. kinks). Re-
place the discharge line. See Table A, col-
umn 2, on page 13 for recommended size.
Retest for air build. Return vehicle to service
or, if problem persists, go to 9.0(a).
 The discharge line must maintain a
constant slope down from the compressor
to the air dryer inlet fitting to avoid low points
where ice may form and block the flow. If,
instead, ice blockages occur at the air dryer
inlet, insulation may be added here, or if the
inlet fitting is a typical 90 degree fitting, it
may be changed to a straight or 45 degree
fitting. For more information on how to
help prevent discharge line freeze-ups, see
Bendix Bulletins TCH-08-21 and TCH-08-22
(Appendix B). Shorter discharge line
lengths or insulation may be required in cold
climates.
Kinked discharge line shown. Dash gauges.
Partly collapsed
inlet line shown.
(f)
(g)
Engine Oil Quality
Inadequate oil change intervals, the formulation of the
oil and/or the quality of oil filter used can all lead to poor
oil quality. These can increase the rate at which carbon
builds up in the discharge line. Bendix recommends oil
soot (solids) be maintained at less than 3%.