Discharge Valves, Valve Stops And Seats; Inlet Valves And Seats; Installing Crankshaft; Piston Comparison - BENDIX TU-FLO 550 COMPRESSOR Manual

with a special lubricant piece number 239379 and need
no additional lubrication. Install the springs and unloader
pistons in their bores being careful not to cut the o-rings.
Install the unloader cover gasket and unloader cover and
secure the cover cap screws. Tighten the cap screws to
175-225 in. lbs. in a crossing pattern after fi rst snugging
all screws.
DISCHARGE VALVES, VALVE STOPS AND
SEATS
If the discharge valve seats merely show signs of slight
wear, they can be dressed by using a lapping stone,
grinding compound and grinding tool, however, it is
recommended that a cylinder head maintenance kit be
used. Install new discharge valve springs and valves.
Screw in the discharge valve seats, and tighten to 70-90
ft.-lbs. Discharge valve travel should be between .030 in. to
.046 in. To test for leakage by the discharge valves, apply
100 psi to the cylinder head discharge port and apply a
soap solution to the discharge valve and seats. Leakage
in the form of soap bubbles is permissible. If excessive
leakage is found, leave the air pressure applied and with
the use of a fi ber or hardwood dowel and a hammer, tap
the discharge valves off their seats several times. This will
help the valves to seat and should reduce the leakage.
With the air pressure still applied at the discharge port of
the cylinder head, check for leakage around the discharge
valve stop on the top of the cylinder head casting. No
leakage is permitted.

INLET VALVES AND SEATS

Inlet valves and springs should be replaced. However, if
the inlet valve seats show signs of slight nicks or scratches,
they can be redressed with a fi ne piece of emery cloth or
by lapping with a lapping stone, grinding compound and
grinding tool. If the seats are damaged to the extent that
they cannot be reclaimed, they must be replaced.
ASSEMBLY
General Note: All torques specifi ed in this manual are
assembly torques and typically can be expected to fall off
after assembly is accomplished. Do not retorque after
initial assembly torques fall unless instructed otherwise.
A compiled listing of torque specifi cations is presented on
page 13 of this manual.
To convert inch pounds of torque to foot pounds of torque,
divide inch pounds by 12.
inch pounds ÷ 12 = foot pounds
To convert foot pounds of torque to inch pounds of torque,
multiply foot pounds by 12.
foot pounds x 12 = inch pounds

INSTALLING CRANKSHAFT

Press new sleeve bearings in the end cover and crankcase.
Ensure that the slot in the bearings line up with the oil
passages in the end cover or crankcase. If you have a
model with no oil passage present in the crankcase, press
the sleeve bearing into the crankcase with the slot located
90 degrees from vertical.
Install the front thrust washer with the tang inserted in

PISTON COMPARISON

2.78
1.25
TU-FLO 550
®
AIR COMPRESSOR
FIGURE 13 - PISTON COMPARISON
the slot toward the fl ange. Insert the crankshaft and the
rear thrust washer with the tang toward the rear of the
compressor.
Place the oil seal ring on the boss of the rear end cover and
install the end cover making sure not to pinch the seal ring.
Ensure the tang of the thrust washer is inserted in the slot
of the end cover. Fasten the end cover to the crankcase
with the four cover cap screws. Torque the cap screws to
175-225 inch pounds in a cross pattern.
FIGURE 14 - PISTON & RINGS
1.06
OTHER BENDIX
®
TU-FLO AIR COMPRESSORS
®
COMPRESSION RING (23)
SEGMENT RING (24)
SPACER RING (25)
SEGMENT RING
(24)
2.17