MCi Crusader II 1989 Maintenance Manual page 138

Date
1-1-89
Page. _ _
4
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MC-9 MAINTENANCE MANUAL
and retighten evenly if necessary. Check for leakage and
proper unloader operation.
Every 12 months. 3,000 operating hours or 100.000 miles
(161.000 km) perform a thorough inspection: disassemble the
compressor. clean and inspect all parts thoroughly. repair or
replace all worn or damaged parts.
CAUTION: Should it be necessary to drain
the engine cooling system to prevent dam-
age from freezing, the cylinder head of the
compressor must also be drained.
TROUBLESHOOTING
If the compressor fails to maintain adequate air pressure 1n
the air system. it usually denotes loss of efficiency because of
wear. provided leakage in the air system ls not excessive. Oil
passing is another sign of excessive wear.
Leakage past the discharge valves can be detected by re-
moving the discharge line. applying shop air back through the
discharge port and listening for escaping air. Also the dis-
charge valves and unloader pistons can be checked for leak•
age by building up the air system until the governor cuts out.
then stopping the engine.
With the engine stopped. carefully listen for escaping air at
the intake. To pinpoint leakage if noted. squirt soapy water
round the unloader pistons. If there is no noticeable leakage at
ihe unloader pistons. the discharge·valves may be leaking.
If
the compressor does not function properly or leakage is
excessive. it can be repaired as described below.
REMOVAL
1.
Block all the wheels to prevent rolling and then vent the air
brake system. Drain engine coolant as described in Section 6
and from compressor block.
2. Disconnect all air lines. water and oil lines to and from
compressor.
3. Remove compressor mounting bolts and compressor
from engine.
. 4. Use a gear-puller to remove the gear from compressor
crankshaft.
DISASSEMBLY
1. Clean compressor exterior of dirt and grease using a
cleaning solvent
2. Before the compressor is completely disassembled the
following items should be marked to show their relationship
when the compressor is assembled: the cylinder block in rela-
tion to crankcase; end covers in relation to crankcase; position
of crankshaft in relation to crankcase; the cylinder head's rela-
'ion to the block. Refer to figure 4-10.
3. Remove capscrews and lift off cylinder head. It may have
to be tapped with a rawhide hammer to break gasket joint.
4. Remove inlet valve springs from head and inlet valves
from their guides in the block. Scrape off cylinder head gasket
from cylinder head and block.
5. Remove discharge valve capnuts and lift ourdischarge
valve springs and valves.
NOTE: The discharge valve seats can be
removed, but it is not necessary unless they
are badly worn or nicked.
ROD ASSEMBLIES:
6. Straighten prongs of connecting rod bolt lockwashers
and remove bolts, lockwashers and bearing caps.
7. Push piston
with
connecting rods attached out the top of
the cylinder block. Replace bearing caps on their respective
connecting rods.
8. Remove piston rings from pistons.
9. To remove pistons from connecting rods. remove wrist pin
lockwire and press wrist pins from pistons and connecting
rods.
NOTE: If connecting rods are aluminum.
do not re-use. Replace with new die cast
aluminum rod assemblies. Steel connect-
ing rods can be reused and re-bushed if
necessary.
10. Remove capscrews securing end cover at drive end of
crankshaft.
CRANKCASE:
11. Remove end cover with oil seal; remove end cover
gasket. Replace oil seal after cleaning end cover.
12. Remove capscrews that hold opposite end cover to
crankcase: remove end cover and its gasket.
13. Press the crankshaft and ball bearings from the crank-
case, then press ball bearings from crankshaft.
BLOCK:
14. If compressor is fitted with an air strainer, inlet elbow or
governor, remove them. .
15.
Remove capscrews securing cylinder block to crank-
case; separate crankcase and cylinder block and scrape off
gasket
16. Remove unloader spring, spring saddle and spring seat
from cylinder block.
17. Remove unloader guides and plunger and
with
the use
of shop air. Blow unloader pistons out of cylinder block
unloader piston bores.
18. Remove inlet valve guides.
NOTE: Inlet valve seats can be removed but
only
if
they are wom or damaged and are
being replaced. Unloader bore bushings
should be inspected but not removed unless
they are damaged.