Bendix Commercial Vehicle Systems TU-FLO 750 COMPRESSOR 6/08 - Manual (Page 12)

12
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 at
the end 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 crank-
case. 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
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.
PISTONS AND CONNECTING RODS
If the pistons are to be replaced ensure that the correct
pistons are being installed. Note that the pistons for the
Tu-Flo
® 750 compressor are similar to those of other Bendix
compressor models but may be identifi ed by the piston
diameter and the distance to the center of the wrist pin from
the top of the piston as shown in Figure 13.
PISTON RINGS
Check each ring end gap in a cylinder bore before installa-
tion. Place the ring in the top of the cylinder bore and using
the piston, push the ring to the midpoint of the cylinder
bore and check the ring gap. If the end gaps are incorrect
either the wrong repair size has been purchased or the
compressor is worn beyond specifi cation and should be
replaced.
FIGURE 13 - PISTON COMPARISON
2.78
2.17
1.06
1.25
OTHER BENDIX ®
TU-FLO ® AIR COMPRESSORS
TU-FLO ® 750
AIR COMPRESSOR
PISTON COMPARISON
Install the rings on the pistons per the following instructions
starting at the center of the piston and moving outward.
1. Install the spacer and segment rings as follows. Place
the spacer ring (25) in the piston groove, the ends of
the spacer must butt and not overlap. Install the top
segment (24) by inserting one end above the spacer
in the ring groove, 120 degrees from the spacer ends
and wind the segment into position. Install the bottom
segment in the same manner beneath the spacer,
making sure the gap is staggered 120 degrees from
both the top ring segment and the spacer end gaps.
Before using be sure both painted ends of the spacer
are visible and butted. (Refer to Figure 14.)
FIGURE 14 - PISTON & RINGS
COMPRESSION RING (23)
SEGMENT RING (24)
SPACER RING (25)
SEGMENT RING (24)