5
Disassembly
1. Disconnect the air tool from the air system.
2. Loosen the back head bolt nuts, remove the lock washer, and back head bolt nuts.
3. Remove the back head from the cylinder and remove the throttle valve, throttle valve spring, plunger,
and plunger spring.
4. Remove the valve guide, valve, valve chest, valve seat, valve chest dowel pin, and piston.
5. Remove the cylinder, tappet seat, and tappet.
6. Disassemble the front head:
•
Loosen the steel retainer bolt nut.
•
Remove the steel retainer bolts, the steel retainer, and the retainer bolt bushings.
•
Remove the steel retainer plunger and the retainer spring.
•
Remove the front head bushing from the front head by pressing it out from the backside using
a 15-ton press.
7. Disassemble the back head:
•
Remove the two throttle lever pins and release the throttle lever.
•
Using a press and a 0.37” (9.4mm) pin, remove the throttle valve stem guide from the back
head.
•
Remove the 5/8” oil control plug from the back head and take out the oil control felt.
8. Disassemble the air inlet:
•
Loosen the air inlet swivel nut and remove it from the cylinder.
•
Remove the air inlet swivel.
•
Remove the air inlet screen from the cylinder.
•
Remove the O-ring(s) from the air inlet swivel nut and air inlet swivel.
Repair Notes
Air Leakage:
•
If air is leaking from the air inlet swivel nut or air inlet swivel, change the O-rings and check for
loosening of the air inlet swivel nut.
•
If air is leaking from the throttle valve area, check for wear of the throttle valve stem guide.
•
If air is leaking from the back head and cylinder, check the plug carefully and change the O-ring on
the throttle valve. Also check for foreign matter, which may have entered during assembly.
Low Impact or Loss of Blows per Minute:
•
Check the clearance between the pistons and the cylinder. The maximum clearance should be 0.005
in. (.13 mm). Check that the piston moves freely and is not seized.
•
Check for valve seizure.
Tool continues to operate after releasing throttle lever:
•
Check the throttle valve seat surface for damage. Also check for foreign material in the valve area.
Chisel is loose:
•
Change the front head bushing.
Steel retainer latch does not catch
•
Check for excessive steel retainer wear.
•
Check for excessive steel retainer plunger and spring wear.
