TST-020 PT-AIR
– REV. 2017-246
Page 9 of 14
5) Observe the vacuum gauge.
If the vacuum level of the lifter’s vacuum gauge holds steady and does not drop: The leak is
located in one or more of the vacuum pads.
Re-attach one pad at a time to determine which vacuum pads are leaking. Repair or
replace as needed.
If the vacuum
level of the lifter’s vacuum gauge starts and continues to drop: Either a leak
exists between the pad fittings and the filter
or
if the lifter has shut-off valves to all the pads
and
step 2
determined that the lifter does not leak up to the shut-off valves, then the leak is
located between the pad fittings and the shut-off valves.
Proceed to step 6.
6) The ball valve with gauge and/or cap plugs can be used to test individual lines, sections, fittings
or parts.
In
FIGURE 8
, caps are used to cap individual sections where, in the first two views, a tee fitting
and a shut-off valve are shown capped-off. Vacuum is then applied so the line up to the
capped off section will be tested. If the leak is no longer present, it indicates that the leak is in
the section past the capped-off part
or
, if the leak continues, that the leak is between the
capped-off part and the filter.
In the right view, caps were used to seal off four pad lines at the manifold.
7) Check individual fittings and parts by attaching the
ball valve to any active vacuum line (see
FIGURE 9
,
where a tee fitting has been removed from its line and
attached directly to the ball valve.) After vacuum is
applied, the ball valve is closed so the only part being
tested is the tee fitting itself. A drop in vacuum on the
ball valve’s vacuum gauge indicates that the tee
fitting leaks. If the vacuum level holds steady and
does not drop the tee fitting does not leak.
This process can be used to test any individual
part, assembly, or section.
Once all leaks have been identified and repaired, proceed to System Confirmation and retest the
vacuum system.
FIGURE 8
FIGURE 9
