Bendix Commercial Vehicle Systems TU-FLO 600 AIR COMPRESSOR 9/04 - Manual (Page 10)

10
CYLINDER BLOCK
Check for cracks or broken lugs on cylinder block. Also
check unloader bore bushings to be sure they are not worn,
rusted or damaged. If these bushings are to be replaced,
they can be removed by running a 1/8 in. pipe thread tap
inside the bushing, then inserting a 1/8 in. pipe threaded
rod and pulling the bushing straight up and out. Do not use
an easy-out for removing these bushings.
INLET VALVES AND SEATS
If inlet valves are grooved or worn where they contact the
seat, they should be replaced. If the inlet valve seats are
worn or damaged so they cannot be reclaimed by facing,
they should be replaced.
CYLINDER BORES
Cylinder bores which are scored or out of round by more
than .002 in. (.051 mm) or tapered more than .003 in. (.076
mm) should be rebored or honed oversize. Oversize pistons
are available in .010 in., .020 in., and .030 in. oversizes (Fig.
16).
Cylinder bores must be smooth, straight, and round.
Clearance between cast iron pistons and cylinder bores
should be between .002 in. (.051 mm) minimum and .004
in. (.102 mm) maximum (Fig. 16).
PISTONS
Any of three different piston designs may be found in Tu-Flo ®
600 compressors as follows: three ring cast iron, three ring
aluminum or five ring cast iron. If either of the three ring
designs are found, it is recommended that the unit be updated
to the current five ring design. Piece numbers of five ring
piston, wrist pin maintenance kits and piston ring sets are
shown in Fig. 17.
If the compressor has five ring pistons which are to be reused,
they should be checked for scores, cracks or enlarged ring
grooves; replace pistons if any of these conditions are found.
Measure each piston with a micrometer in relation to the
cylinder bore diameter to be sure the clearance is between
.002 in. (.051 mm) minimum and .004 in. (.102 mm)
maximum.
Check fit of wrist pins in pistons. Wrist pin clearance should
be from .0000 in. to .0006 in. (.015 mm). Check fit of wrist
pin in connecting rod bushing. This clearance should not
exceed .0007 in. (.018 mm). Replace wrist pin bushings if
excessive clearance is found. Wrist pin bushings should be
reamed after being pressed into connecting rods. Replace
used wrist pin lock wires. Compressors manufactured after
December, 1977, will have Teflon plugs in each end of the
wrist pins instead of the lockwire. The Teflon plugs (piece
number 292392) may be used instead of the lockwires on
all compressors (see Fig. 3).
PISTON RINGS
Check fit of piston rings in piston ring grooves. Check ring
gap with rings installed in cylinder bores. Refer to Fig. 18 for
correct gap and groove clearance.
All rings must be located in their proper ring grooves as
shown. The rings can be identified by the width and should
be installed with the bevel or the pip mark (if any) toward the
top of the piston as shown.
FIGURE 16 - CHECKING CYLINDER BORE
FIGURE 17
5 Ring Wrist Ring *Piston Pin
Size Piston Pin Set Maint. Kit
Standard 292529 292530 282525 289891
.010”
Oversize 292547 292530 282526 289892
.020”
Oversize 292548 292530 282527 289893
.030”
Oversize 292549 292530 282528 289894
* Includes 1 piston, 1 wrist pin, and 2 pin buttons.