Tightening And Torquing Bolts - JLG 400S Service And Maintenance Manual

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 THE 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 pressur-
ized 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 the o-rings or gaskets meet on the exterior of the unit
and then checking for air bubbles. 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.
3121671
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 cap screws in a bolt
circle.
1. Tighten (but do not torque) bolt A until snug.
BOLT A
Figure 3-36. 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.
BOLT B
3-43