Description - Chevrolet 1988 Light Duty Truck Repair Manual

DA-V5 AIR CONDITIONING COMPRESSOR
SUBJECT
D escrip tion ......................................................................................................................................................} ................................ 1B 4- 1
Theory of O p e r a tio n ..................................................................................................................................................................1B 4-
Minor Repair to the C o m p re s s o r...............................................................................................................................................1 B 4- 4
Clutch Plate and Hub Assembly R e p la c e m e n t................................................................................................................ 1B 4- 4
Pulley and Bearing Assembly R e p la c e m e n t.................................................................................. .................................. 1B 4- 5
Clutch Coil R eplacem en t.......................................................................................................................................................... 1B 4- 7
Pressure Relief Valve R e p la c e m e n t..................................................................................................................................... 1B 4-
High-Side Pressure and High-Side Low Pressure Cutoff Switches R ep la c e m e n t...............................................1B 4- 9
Control Valve R eplacem ent......................................................................................................................................................1B 4- 9
Major Repair to the C o m p re s s o r...............................................................................................................................................1B 4 - 9
Shaft Seal R e p la c e m e n t...........................................................................................................................................................1B 4- 9
Rear Head, Head Gasket, Rear Valve Plate, Suction Reed Plate and
Cylinder to Rear Head Seal R e p la c e m e n t..................................................................................................................... 1B4-11
Leak T e s t in g .................................................................................................................................................................................... 1B 4-12
S p e c ific a tio n s .................................................................................................................................................................................. 1B 4 -13
Special T o o ls ................................................................................................................................................. j ................................ 1B 4-14
W hen servicing the Harrison DA-V5 compressor, keep
dirt and foreign material from getting on or into the com ­
pressor parts and system. Clean tools and a clean work
area are im portant for proper service. The com pressor
connections and the outside of the com pressor should be
cleaned before any " on vehicle" repairs, or before re­
moval of the compressor. The parts must be kept clean at
all tim es and any parts to be reassem bled should be
cleaned with Trichloroethane, naptha, Stoddard solvant,
kerosene or equivalent solvent and dried with dry air. Use
only lint free cloths to wipe parts.
Drain the com pressor and measure the am ount of oil.
Replace with new 525 viscosity refrigerant oil. Refer to
" S pecifications" (figures 1, 2, 3 and 4).
NOTICE: R em ove th e o il d ra in p lu g to m ake sure
the c o m p re s s o r is d ra in e d c o m p le te ly o f o il (fig ­
ure 1).
THEORY OF OPERATION
The DA-V5 is a variable displacem ent com pressor that
can match the autom otive air conditioning demand under
all conditions w ithout cycling. The basic com pressor
mechanism is a variable angle w obble-plate with five
axially oriented cylinders. The center of control of the
com pressor displacem ent is a bellows actuated control
valve located in the rear head of the com pressor that
senses com pressor suction pressure. The wobble-plate
angle and com pressor displacem ent are controlled by the
crankcase-suction pressure differential. When the AC
SECTION 1B4
CONTENTS

DESCRIPTION

A.
capacity demand is high, the suction pressure will be
above the control point; the valve will maintain a bleed
from crankcase to suction; no crankcase-suction pressure
differential; and the com pressor will have m axim um
displacem ent. W hen the AC capacity demand is lower
and the suction pressure reaches the control point, the
valve will bleed discharge gas into the crankcase and
close off a passage from the crankcase to the suction
plenum. The angle of the wobble-plate is controlled by a
force balance on the five pistons. A slight elevation of the
crankcase-suction pressure differential creates a total
force on the pistons resulting in a m ovem ent about the
wobble-plate pivot pin that reduces the plate angle.
The crankcase-suction bleed is routed through the
rotating wobble-plate for lubrication of the w obble-plate
Figure 1- Mounting View
1B4-1
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