Bendix Commercial Vehicle Systems BX2150 AIR COMP (BW1424) - Manual (Page 12)

12
CONNECTING RODS
The BX-2150 ™ compressor connecting rod does not
incorporate replaceable crankshaft journal bearing inserts
and must be replaced if excessively worn. Clearance between
the crankshaft journal and the connecting rod bearing must
not be less than .001 inch or more than .0025 inches.
REPAIRS
It is generally recommended that genuine Bendix service
parts and maintenance kits be used whenever the
compressor is disassembled. A listing of the most common
kits and their contents can be found in the back of this
manual.
ASSEMBLY
TORQUES
All torques specified in this manual are assembly torques
and can be expected to fall off after assembly is
accomplished. Do not retorque after initial assembly
torques fall.
To convert pound inches of torque to pound feet of torque,
divide inch pounds by 12.
pound inches = pound feet
12
To convert pound feet of torque to pound inch of torque,
multiply pound feet by 12.
pound feet x 12 = pound inches
CYLINDER HEAD ASSEMBLY
1. If the discharge valve stop was removed and must be
replaced, a sealant such as “LOCKTITE RETAINING
COMPOUND #75”, must be applied to the stop and its
corresponding bore in the cylinder head. Before applying
the sealant, make certain that the press fit between the
discharge valve stop outside diameter and the valve stop
bore in the cylinder head is a minimum of .0013 inches
and a maximum of .0028 inches. If this fit cannot be
maintained, a new cylinder head body must be used.
Be sure to completely support the outside top of the
cylinder head casting, while pressing in the replacement
stops.
IMPORTANT: The cylinder head must be supported in a
fashion that allows the machined head surface to be
parallel to the arbor press bed and perpendicular to the
press ram. This is necessary to permit the discharge
valve stop to be installed squarely in its bore and to
minimize the possibility of “cocking”.
2. Install the discharge valve spring, discharge valve and
valve seat. Using a 9/16” Allen wrench torque the
discharge valve seat to 70-90 pound feet.
3. Test for leakage by the discharge valve. Apply 100 psi of
air pressure through the cylinder head discharge port
and apply a soap solution to the discharge valve and
seat. A slight 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 fiber or hardwood
dowel and a hammer, tap the discharge valve off its seat
several times. This will help the valve 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 exposed on the top of
the cylinder head casting. No leakage is permitted.
4. If the unloader piston bushing was removed, press in a
new bushing following the same pressing procedures
given in Step 1. The inside diameter of the unloader piston
bushing must be between .7497 inches and .7460 inches
after pressing.
5. Using a 3/8" Allen wrench install the unloader piston
stop and o-ring in the head. Torque to 175-225 pound
inches.
6. Install the unloader piston and o-ring in the head so that
the short stem of the piston rests on the unloader stop.
7. Install the unloader piston spring, small end first, on the
stem of the unloader piston. Install the metal (copper)
inlet valve gasket so that it rests on the shoulder of the
inlet valve cavity. Install the inlet valve seat on top of the
inlet valve gasket with its beveled side visible. Make
certain the large coils of the piston spring rest within the
recess of the inlet valve seat on the side opposite the
bevel. Install the inlet valve so that it rests on the beveled
side of the valve seat.
8. Install the inlet valve spring on the inlet valve stop and
install the stop in the head. Using a spanner wrench,
torque the inlet valve stop to between 70-90 pound feet.
9. Apply 100 psi air pressure to the unloader port of the
governor mounting pad and note the inlet valve is driven
away from its seat. Using a soap solution, test for air
leakage at the unloader piston stop. No leakage is
permitted.
CRANKCASE & CRANKSHAFT ASSEMBLY
1. If the compressor requires a drive end crankshaft oil seal,
press it into the crankcase until it is flush with the
crankcase casting. Using clean oil lubricate the sealing
lips of the seal.
2. 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. NOTE: In the case of compressors with a
rear main ball bearing, make certain to install the thrust
bearing in the crankcase before pressing the crankshaft