GMC 4000 Series Service Manual page 66

V e n t W in d o w G la ss
N y lo n Friction
Figure 2 3 — Door Vent W in d o w Installed
rubber filler. Lightly tap channel with rubber ham­
mer to firmly seat channel over glass and filler.
6. Install assembled window into door in re­
verse order of "Removal" procedures.
NOTE: When inserting glass assembly into
door run channels, be careful not scratch or place
undue stress on glass. After installation, raise
and lower window to check for binding. If binding
occurs, adjust appropriate run channels by loosen­
ing applicable channel attaching screws.
DOOR W IN D O W GLASS HORIZONTAL
SEALS REPLACEMENT
1. Remove access panel from bottom of door.
This will remove window stop attached to access
panel and allow top of window to be lowered to a
point below horizontal weatherstrips.
2. Using a flat-blade screwdriver, pry wea­
therstrips from door (fig. 22).
3. Install weatherstrips to door, making sure
retaining clips are fully engaged.
4. Raise window, then install access panel to
bottom of door.
DOOR W IN D O W RUN
CHANNEL REPLACEMENT
1. Remove door window as explained previ­
ously under "Door Window Glass Replacement."
2. Remove applicable screw s which attach
either division channel or run channel to door
framing (fig. 16) and lower channel(s) through
access opening at bottom of door.
3. Install channel(s) in reverse order of re­
moval procedures.
G M C S E R V I C E M A N U A L
P ivot Scre w
D iv is io n
V e n t W i n d o w Top
C h a n n e l
R e ta in in g Sc re w s
Scre w
A C C E S S H O L E T O P IV O T S C R E W
V e nt W in d o w Outer
Fram e a n d Rubber Seal
D ivision C hann el
Fram e To D o o r Screw
Fram e To D ivisiona l
C h a n n e l Screw
Friction
C la m p
JffT T H f.J_
Figure 2 4 — Rem oving Vent W indow
4. Install and adjust window glass as explained
previously under "Door Window Glass Replace­
ment."
DOOR VENT W IN D O W TENSION
ADJUSTMENT
Cab vent windows are of friction type having
a positive theft-resistant latch. Friction mechan­
ism consists of a bushing attached at lower end of
vent shaft which rotates in a stationary friction
clamp.
If friction mechanism is adjusted too tight, it
will be difficult to open or close vent. Too loose an
adjustment will result in a fluttering vent or one
having a tendency to close with wind pressure.
If necessary to change vent friction, perform
procedures as follows:
1. Remove access trim panel attached to door
just below vent window with five screws. Figure 23
shows access opening to friction components.
2. Using screwdriver, turn clamp screw (fig.
23) to obtain two to four pounds torque while mov­
ing vent window from a ten-degree open position to
a full-open position. Use either a push or pull-type
spring scale positioned at rear edge of glass.
Sec. 1
Page 59
TILT CAB