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THE LEAK TEST
The purpose of a leak test is to make sure the unit is airtight. To
perform a leak test, use the leak test fixture from the table
below. If the tool is not available, the gearbox must be sealed
to perform the test. This can be accomplished by assembling
the sealed input device onto the gearbox at the input end and
replace one of the oil plugs with an air chuck.
DO NOT EXCEED 10 PSI PRESSURE DURING LEAK TEST.
Higher pressure will create a false sealing effect in assemblies
with lip-seals. The unit has a leak if the pressure gauge reading
on your leak check fitting starts to fall after the gearbox has
been pressurized and allowed to equalize.
Leaks will most likely occur at the pipe plugs, the main seal or
wherever O-rings or gaskets are located. The exact location of
a leak can usually be detected by brushing a soap and water
solution around the main seal and where O-rings or gaskets
meet on the exterior of the unit and then checking for air bub-
bles.
If a leak is detected in a seal, O-ring, or gasket, the part must
be replaced and the unit rechecked. Leak test at 10 psi for 20
minutes.
31215019
SECTION 3 - CHASSIS & TURNTABLE
Tightening and Torquing Bolts
If an air impact wrench is used to tighten bolts, extreme care
should be taken to ensure the bolts are not tightened beyond
their specified torque. The following steps describe how to
tighten and torque bolts or socket head capscrews in a bolt
circle.
1.
Tighten (but do not torque) bolt A until snug.
Figure 3-25. Bolt Tightening Sequence
2. Go to the opposite side of the bolt circle and tighten
bolt B until equally snug.
3. Crisscross around the bolt circle and tighten the remain-
ing bolts.
4. Use a torque wrench to apply the specified torque to
bolt A.
5. Using the same sequence, crisscross around the bolt cir-
cle and apply an equal torque to the remaining bolts.
3-11
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