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6-82
DOORS
the engine compartment and is connected to the
engine manifold by a hose (Fig. 6-107). A check
valve at the tank connector maintains the vacuum in
the tank. The storage tank supplies vacuum at all
times to the remote valve and door lock control
valve. The tank should provide a minimum of three
complete cycles of operation (lock and unlock) im-
mediately after the engine has been shut off.
VACUUM DOOR LOCK TROUBLE
DIAGNOSIS PROCEDURE
When an external air leak in the vacuum locking
system is not severe enough to be heard, the leak-
down testing device shown in Figure 6-111 will aid
in determining which part is leaking. This device
can be easily constructed from common items that
are normally available. The following chart lists
the necessary components. The item numbers are
referenced to Figure 6-111.
Although several transparent glass containers may
be satisfactory for use as a testing device, a quart
jar
with a metal cap that can be sealed i s
recommended.
2. Raise hood and remove storage tank to remote
control valve hose (red) from storage tank
check valve.
3. Install hose from testing device (hose without
port) to bottom of check valve on storage tank.
4. Install other hose (with attached port) on test-
ing device to hose leading to remote control
valve.
5. Set testing device in an upright position.
b. Recharging Vacuum Storage Tank
Vacuum will usually have been depleted after four
or five cycles of lock operation, or after testing
device has been installed. To recharge storage
tank to normal vacuum (22-24 inches of mercury),
proceed as follows:
1. Turn testing device on its side until glass tube
is out of water.
2. Start
engine and run for approximately 1
minute.
Item
1
2
3
4
5
6
7
8
Description
Quart Glass
Container
Metal Cap
Cap Sealing
Ring
Cap Ports
Hose Port
Hose
Hose
Glass Tube
ID
3/16"
3/16"
7/32"
5/32"
1/8"
OD
1/4"
1/4"
3/8"
5/16"
Length <
2 1/2"
2 1/2"
2 "
1"
5/16" to 3/8"
4"
1
1
1
2
1
2
1
1
Install ports in cap by drilling 2 holes and inserting
ports half-way through cap. Solder ports to cap to
make an air-tight seal.
NOTE:
There cannot be any air leaks in leak-
down testing device to check a vacuum system.
The lower end of the glass tube in the jar should
be cut on a 45° angle. If glass tubing is not
available, plastic tubing may be substituted pro-
vided it has the specified inside diameter.
a. Installation of Testing Device Into
Vacuum System:
The testing device is installed between the vacuum
storage tank and the remote control valve. To in-
stall testing device, proceed as follows:
1. Add water to jar until level is approximately
1" above lower end of tube.
3. Turn engine off and return testing device to a
normal upright position.
NOTE:
If water rises in glass tube, quickly
pinch-off hose leading from testing device to
remote control valve. If hose is not pinched,
and then disconnected, water rising up tube will
enter vacuum lock system components. Condi-
tion is the result of a defective storage tank
which must be replaced, provided hose con-
nections check out satisfactory.
4. Allow 15 to 30 seconds for water in testing
device to stop bubbling. The waiting period is
necessary due to different pressures in the
system on both sides of testing device. The
bubbling is the result of these pressures trying
to equalize themselves. The storage tank may
be recharged as often as required when check-
ing vacuum system for an external air leak.
CAUTION:
Be certain to turn testing device
on its side each time system is recharged. If
this is not done, water in jar may be drawn up
into vacuum system components.
c. Determining Size of Air Leak from Bubbles
in Testing Device:
If bubbles appear in water at a rate of approxi-
mately one every fifteen seconds or faster, an air
leak is present at either the remote control valve
or door selector valve. This assumes, of course,
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