Disassembly and Reassembly
52
6. Remove the wrist pin from the piston and rod.
The wrist pin is a float fit so you should be
able to press it out by hand.
7. Remove the piston from the rod.
8. Inspect the piston, piston head, and ring valve
for wear or damage. Replace the complete
piston assembly if the ring valve is worn,
cracked, broken or missing, if excessive
grooves are worn into the ring valve from the
piston grooves, or if the piston grooves are
worn flat from the ring valve.
NOTE: The grooved piston supersedes the
flat top piston. The grooved piston has small
concentric grooves on the top of the piston
under the ring valve. These grooves reduce
the stiction between the top of the piston and
the ring valve. The grooved and flat top
pistons are interchangeable, but the piston
components are not. Do Not Use Flat Top
Pistons.
9. Inspect the wrist pin for wear or damage.
Measure the wrist pin if it shows signs of
wear. If the outside diameter of the wrist pin is
less than 0.6250 in. (15.8750 mm), replace the
piston assembly.
10. Inspect the wrist pin bushing in the small end
of the connecting rod for wear or damage.
Measure the wrist pin bushing. Replace the
wrist pin bushing if its inside diameter is more
than 0.6258 in. (15.8953 mm).
11. Inspect large end of connecting rod for wear
or damage.
NOTE: Thermo King does not recommend
reinstalling used connecting rod bearings.
Use new bearings for inspecting the
connecting rod and the crankshaft.
12. Place the bearing in the rod. It should fit into
the machined radius snugly when pushed with
the thumb. When the bearing is bottomed out,
both ends of the bearing should be flush with
the mating surfaces of the rod. The bearing
should fit into the rod cap in the same manner.
NOTE: Be sure to align the tabs in the
bearings with the notches in the mating
parts.
1.
Piston
4.
Piston Head
2.
Wrist Pin
5.
Ring Valve
3.
Snap Ring
Figure 75: Piston Components
1
4
5
3
ARC014
2
1.
Check Bearing Fit
2.
Check Bolt for Damage
Figure 76: Inspect Connecting Rod
1.
Check Bearing Fit
2.
Check Bolt Holes for Damage
Figure 77: Inspect Connecting Rod Cap
1
2
AGA566
2
1
2
AGA567
