Chevrolet Light Duty Truck 1973, Руководство по обслуживанию

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9 -1 6 STEERING
POW ER STEERING PUM P
PUMP DESCRIPTION
The housing and internal parts of the pump are inside
the reservoir so that the pump parts operate submerged
in oil. The reservoir is sealed against the pump housing,
leaving the housing face and the shaft hub exposed. The
reservoir has a filler neck fitted with a cap. A shaft
bushing and seal are pressed into the housing from the
front. The drive shaft is inserted through this seal and
bushing. A large hole in the rear of the housing contains
the functional parts; namely ring, rotor, vanes and
plates. A smaller hole contains the control valve
assembly and spring (Fig. 22).
The thrust plate (Fig. 23) is located on the inner face of
the housing by two dowel pins. This plate has four
central blind cavities for undervane oil pressure. The two
outer blind cavities direct discharge oil through the two
cross-over holes in the pump ring (Fig. 23), through the
pressure plate, and into cavity l (Figs. 25, 26 and 27).
The two outside indentations in the thrust plate are for
intake of the oil from the suction part of the pump.
The pump ring (Fig. 23) is a plate having the mating
surfaces ground flat and parallel. The center hole is a
two lobed cam in which the rotor and vanes operate. The
ring is placed next to the thrust plate, and located with
the same dowel pins.
The pressure plate is fitted against the ring and located
with the same two dowel pins. This plate has six through
ports. The four central through ports connect from cavity
l (Figs. 25, 26 and 27) to supply undervane oil pressure.
The two outer ports pass oil under discharge pressure to
cavity 1. The two identations are for oil intake from the
suction part of the pump, cavity 7 (Figs. 25, 26 and 27)
into the rotor.
The reservoir is for oil storage. It receives and directs the
return oil back to the make-up passage of the pump.
The drive shaft is fitted with a pulley and is belt driven
from the crankshaft. The rotor is loosely splined to the
drive shaft and secured with a retaining ring. It is
located centrally within the ring and between the thrust
and pressure plates. The ten vanes are mounted in radial
slots in the rotor (Fig. 23).
PUMP OPERATION (Fig. 24)
The mode of operation of the power steering pump is
based upon the demand of the power steering gear. The
various major modes of operation are: Slow cornering,
moderate to high speed straight ahead driving, and
cornering against the wheel stop. The pump is designed
to recognize these conditions as required by the steering
gear valve and compensates for them internally.
As the drive shaft turns the rotor, the vane tips follow
L-6 AND
SMALL V-8
MARK V-8
18 19 20
(JSr-Q rm
1 2 3
4 6 7 8 9 10
tu p 0 o
1 1
1 12 13 14 15 16 17 21 22 23
1. Union
2. Union " 0 " Ring Seal
3. Mounting Studs
4. Reservoir Mark Engine & Truck
4A. Reservoir L-6 and Small V-8 Only
5. Dip Stick and Cover
6. Element (Corvette only)
7. F ilter Assembly (Corvette only)
8. End Plate Retaining Ring
9. End Plate
10. Spring
11. Pressure Plate
12. Pump Ring
13. Vanes
14. Drive Shaft Retaining Ring
15. Rotor
16. Thrust Plate
17. Dowel Pins
18. End Plate " 0 " Ring
19. Pressure Plate " 0 '''R in g
t
25 26 27
20. Mounting Stud Square Ring
Seals
21. Flow Control Valve
22. Flow C ontrol Valve Spring
23. Flow Control Valve Square
Ring Seal
24. Pump Housing
25. Reservoir ''O '' Ring Seal
26. Shaft Seal
27. Shaft
Fig. 22—Power Steering Pump—Explode
LIGHT DUTY TRUCK SERVICE MANUAL