IMT DA435HAR, User Manual, Page: 21 / 34

DA435HAR: 99900683: 5-1
SECTION 5. REPAIR
19951220
5-1. GENERAL
This section describes the disassembly and assembly
procedures for the air compressor. In all cases,
remove the compressor from the vehicle before
proceeding with disassembly and repair within a
clean environment. Refer to the parts drawing in
section 4 of this manual for parts locations.
5-2. PISTON RING REPLACEMENT
1. Remove the pulsation tank.
2. Unscrew the head bolts and remove the heads.
NOTE
A RUBBER FACED MALLET WILL HELP WHEN
REMOVING THE HEAD. TAP THE SIDES OF THE HEAD
CAREFULLY UNTIL THE HEAD IS LOOSE. LIFT OFF
THE HEADS.
3. Remove the cylinder bolts. Tap the sides of the
cylinder several times to break it loose from the
gasket. Rock the cylinder back and forth and lift
until it is free. Lift it off the pistons.
4. Use a single edged razor blade, or sharp
putty knife, to remove the old gasket material.
CAUTION
DO NOT ALLOW THE GASKET MATERIAL TO FALL INTO
THE CRANKCASE. DO NOT NICK THE HEAD,
CYLINDER, OR CRANKCASE MATING FACES WHILE
REMOVING THE OLD GASKET. REMOVE ALL OF THE
OLD GASKET MATERIAL TO PROVIDE A SMOOTH,
CLEAN SURFACE FOR THE NEW GASKET. FAILURE
TO FOLLOW THIS PROCEDURE MAY RESULT IN THE
NEED TO RESEAL THE UNIT LATER.
5. Hone the cylinder to break the glaze and to
remove the buildup at the top of the cylinders.
6. Measure the inside diameter of the cylinder for
roundness and excessive wear. The bore should be
2.625" (0.0025" tolerance). If the bore is oversized,
the cylinder must be replaced.
7. With a ring expander, remove the compression
and oil rings.
8. With the ring expander, install the new ring kit.
Make certain that the oil ring is on the bottom and
the beveled inside edge of the compression ring is
toward the top of the piston.
9. Position the cylinder base gasket on the
crankcase. Use a few drops of oil to hold it in
position. Install the cylinder block spacer and gasket
on the crankcase.
10. Rotate the rings so that the gaps of the three
rings are 120° apart. Lightly lubricate the inside of
the cylinder. Rotate the crankshaft so that a piston is
at the top of the stroke. Compress the rings with a
ring compressor, and slide the cylinder over the
piston. Repeat for the other piston.
CAUTION
DO NOT LUBRICATE THE RINGS. USE A LIGHT
LUBRICANT, SUCH AS WD-40 ONLY, ON THE
CYLINDER WALLS. OILING THE RINGS WILL
PREVENT THEM FROM SEATING AND CAUSE
EXCESSIVE OIL CONSUMPTION.
FIGURE E-2. CYLINDER HEAD TORQUE
SEQUENCE
FIGURE E-1. PISTON RING
ORIENTATION