4-28. ENGINE - Continued
d. Unloader Removal
If unloader service is required with the air
compressor mounted to the truck engine,
drain the air tanks.
(1) Remove two unloader cover bolts (2) and one
cylinder head bolt (1), then lift the unloader cover
(3) from the cylinder head (4).
(2) Remove and discard gasket (5).
(3) Remove unloader pins (7) and springs (8) from
cylinder head (4). Remove O-rings (6) from pins
(7) and discard.
e. Cylinder Head Removal and Disassembly
(1) With the cylinder head still mounted, remove the
air pressure outlet fitting (4) from the top of the
cylinder head (1), by removing capscrews (5).
(2) To remove the cylinder head (1) from the block
(2), remove the five remaining capscrews (3).
(3) Using a soft faced hammer, gently tap the
cylinder head (1) to loosen it from the block (2).
(4) Lift cylinder head (1) from block (2).
(5) Remove and discard the cylinder head gasket
(6) To disassemble cylinder head (1), remove
unloader as detailed in d. preceding, then
proceed to step 7.
(7) Place cylinder head (1) on workbench, with
bottom side up.
(8) Using a 9/16 in. allen wrench remove the
exhaust valve seat (7). Remove the exhaust
valve (8), exhaust valve spring (9) and washer
(10) from both exhaust valve ports.
(9) Using a spanner wrench (or Kent Moore J25447
A) remove the inlet valve cages (12), inlet valve
springs (13), inlet valves (14), inlet valve seats
(15), and washers (16).