Servicing E.c .S; Canister(S); Canister Filter; Hoses And Lines - GMC 1976 ZEO 6083 Maintenance Manual

CANISTER(S)
The plastic canister is filled with charcoal which
adsorbs and stores fuel vapors . When fuel is drawn
from the tank during engine operation, a fuel cap
tank relief valve opens allowing air to be drawn into
the tank . When the engine is running, air is drawn
in through the bottom of the canister . This air picks
up vapors which are being held in the charcoal and
carries them through the carburetor into the engine
where they are burned .
REMOVAL
1 . Vehicle may be raised if desired .
2. If vehicle is equipped with one canister loosen
clamp screw and lift canister up and out.
3. If vehicle is equipped with two canisters
remove the lower canister clamp from bracket and
slide canister and clamp out . See Figure 1 .
4. Disconnect hoses from canister(s) .
5 . If vehicle is equipped with a second canister
loosen clamp and lower canister enough to discon-
nect hoses so it may be removed .
INSTALLATION
1 . If the vehicle is equipped with two canisters
connect hoses to the upper canister and install.
Tighten clamp.
2. Connect hoses to remaining canister and in-
stall. Tighten clamp as required .
CANISTER FILTER
REMOVAL
1 . Remove canister . Refer to "Canister-Re-
moval" earlier in this section.
2. Filter is located in the bottom of the canister .
If vehicle is equipped with two canisters the filter is
in the lower canister .
3 . Remove filter .
INSTALLATION
1 . Install filter . See Figure 2.
2. Install canister . Refer to "Canister-Installa-
tion" earlier in this section .
SERVICING E .C .S .
Conventional steel tubing, vapor resistant hose
and hose clamps are used to connect the various
components of the system . It is extremely important
that all pipes and hoses are not kinked, are properly
connected, and that all connections are tight. This is
necessary to assure a vent through the system for the
fuel tank to prevent restriction of vapors to the canis-
ter. Thorough visual inspection is and will remain
one of the most important checks of the system .
IMPORTANT :
Use only hose marked "EVAP" or
"GM 6107M" if necessary to replace an E.C .S .
hose . Gasoline vapors will deteriorate other
types of hoses.
LIQUID/VAPOR SEPARATOR
DESCRIPTION
An external liquid-vapor separator is mounted to
left rear wheel opening liner. It's purpose is to stop
fuel that has drained out of tanks when the vehicle
is parked off level. Once a level position is assumed
the fuel in the separator will drain back into the tank .
Any vapors collected in the separator are routed
to the canister by a hose . The separator can not be
serviced . If damaged it must be replaced .
REMOVAL
FUEL TANK AND EXHAUST 8- 3
Figure 2-Replacing Canister Filter
HOSES AND LINES
1 . Clean threads of dirt and remove attaching
nuts .