Bendix Commercial Vehicle Systems TU-FLO 501 AIR COMPRESSOR 9/04 - Manual (Page 10)

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If the compressor uses a ball type main bearing, press the
ball bearing onto the correct end of the crankshaft. Position
the ball bearing and the crankshaft in the crankcase, making
sure the drive end of the crankshaft is positioned in the
crankcase as marked before disassembly. Carefully press
the crankshaft and ball bearing into the crankcase using an
arbor press.
In the case of compressors with a front ball bearing, place
two small seal rings in the counter-sunk holes at the front of
the crankcase, as well as an end cover gasket. Install the
front end cover in the proper position as marked before
disassembly, taking care not to damage the new oil seal.
In the case of compressors with a rear ball bearing, place
two small seal rings in the counter-bore at the rear of the
crankcase. In one case a gasket is used and in another a
large o-ring is placed in the counterbore at the rear of the
crankcase. These are in addition to the seal rings. Install
the rear end cover in the proper position as marked before
disassembly. Since June, 1978, the two small seal rings
have been increased slightly in cross section and a retaining
ring added, as shown in Figure 15.
Secure the flange adapter, front or rear end cover to the
crankcase by tightening the four cap screws. See note below
for torque.
Note: For cast iron flange adapters, torque the four 7/16
in. cap screws to 38-45 foot pounds. For die cast
aluminum end covers, torque the four 7/16 in. cap
screws to 25-30 foot pounds. All end covers using
5/16 in. cap screws or stud and nuts are torqued
to 15-18 foot pounds. For through drive compressors
with a cast iron end cover, torque the four 7/16 in.
cap screws to 25-30 foot pounds.
Pistons and Connecting Rods
If new wrist pin bushings are to be used, they should be
pressed into the connecting rods so that the oil hole in the
bushing lines up with the one in the rod. The new bushings
should then be reamed or honed to provide between .0001
in. (.00254 mm) and .0006 in. (.01524 mm) clearance on
the wrist pin. Position the connecting rod in the piston and
press in the wrist pin.
Pistons installed in compressors manufactured prior to
November, 1976, will have the wrist pin secured in the piston
by a lock wire extending through matching holes in wrist pin
and piston boss, anchored in a hole in the side wall of the
piston. If the original pistons are used the wrist pin must be
pressed in so the hole in the wrist pin aligns with that of the
piston and secure same by inserting the new lockwire
through the hole in piston and wrist pin and lock the wire by
snapping the short 90° section into the lockwire hole in the
bottom of the piston.
Compressors built after November, 1976, will have the wrist
pin secured by Teflon buttons in either end of the wrist pin,
allowing the wrist pin to float. The Teflon buttons pc. no.
292392 may be used with either new or old wrist pins. The
later design pistons have two rings above the wrist pin and
one below. Install the piston rings in the correct location
with the ring pipmarks up. Stagger the position of the ring
gaps. Pre-lubricate the piston, piston rings, wrist pins and
connecting rod.
Unloader
A new unloader kit should used when rebuilding. (Figure
14). (Piece Number 279615). The unloader pistons in the kit
are pre-lubricated with a special lubricant piece number
239379 and need no additional lubrication. Install the unloader
pistons in their bores being careful not to cut the o-rings.
Position the unloader plungers in their guides and slip them
in and over the tops of the pistons. Install the unloader spring
seat in the crankcase inlet cavity; a small hole is drilled in
the crankcase for this purpose. Position the saddle between
the unloader piston guides, so its forks are centered on the
guides. Install the unloader spring, making sure it seats
over the spring seats both in the crankcase and on the saddle.
FIGURE 15
SEAL RING
SEAL RING
O-RING RETAINER
OLD
NEW
In the case of compressors with a sleeve bearing either front
or rear, place the two small seal rings in the counter-sunk
holes in the crankcase. Caution: An end cover gasket must
not be used. Place the o-ring seal in the groove around the
flange adapter or the end cover, and affix the thrust washer.
Install the flange adapter or end cover in the proper position
as marked before disassembly, taking care not to damage
the sleeve bearing.