Power Steering Gear And Pump - Jeep 1979 CJ-5 Technical & Service Manual

S E C T I O N I N D E X
Page
Paga
General Information 2L-1
Power Steering Purap
Power Steering Gear 2L-19 Tools 23.-44
G E N E R A L I N F O R M A T I O N
Page
Description and Operation
2L-1
General
2L-1
Hydraulic Pressure Test 21-1S
Leak Diagnosis 2L-10
GENERAL
The power steering system consists of a power steer-
ing gear, hydraulic pump, and interconnecting hoses.
The system fluid supply is contained in a reservoir
mounted on the pump. Fluid from the pump is supplied
to the gear through the interconnecting pressure and
return hoses. The pump is operated by a drive belt
mounted on pulleys attached to the pump shaft and
engine crankshaft.
Two different ratio steering gear units are used. CJ
models use a constant ratio gear with a 17.5:1 steering
ratio. Cherokee, Wagoneer and Truck models use a vari-
able ratio gear with a 16:1 ratio on center and 13:1 ratio
at full lock.
Although the steering ratios of the two units differ,
exterior appearance and service procedures for both
units are the same. However, the internal components of
the two gears are not interchangeable.
A vane-type power steering pump with a combination
flow control/relief valve is used on all models. Two valve
calibrations are used. On CJ models, the valve is cali-
brated to open at 1100 psi (7 584 kPa). On Cherokee,
Wagoneer, and Truck models, the valve is calibrated to
open at 1500 psi (10 342 kPa).
The power steering gear is designed to operate man-
ually if a system malfunction should ever occur. This
feature provides the driver with continued steering con-
trol of the vehicle. In this condition, the gear operates
like a manual steering gear; hydraulic fluid is bypassed
through the gear valve body to allow manual operation.
Pap
Periodic Maintenance 21-15
Service Diagnosis
21-5
SpieifiBiiioifs
2L-'3?
N O T E : The power steering gear and pump form a
closed system,. Contaminants or foreign material must
not be allowed to enter the system at any point. If either
the gear or pump become contaminated, or incur dam-
age extensive enough to produce debris, both com-
ponents must be disassembled, cleaned, and serviced.
DESCRIPTION AND OPERATION
Steering Gear
The power steering gear is a recirculating ball-type
unit (fig. 2L-1). Steel ball bearings act as a rolling thread
between the steering gear wormshaft and rack piston.
Two different ratio gears are used. CJ models use a
constant ratio gear with 17.5:1 steering ratio. Cherokee,
Wagoneer and Truck models use a variable ratio gear
with 16:1 steering ratio on center and 13:1 at full lock.
Although the two gears have different steering ratios,
exterior appearance, diagnosis, and service procedures
are the same for both.
Steering gear wormshaft fore and aft thrust is con-
trolled by a bearing and two races at the lower end, and
a bearing assembly in the adjuster plug at the upper
end. The lower bearing races are conical in shape. This
design maintains constant preload on the wormshaft to
prevent loss of thrust bearing preload. The adjuster plug
provides initial worm bearing preload and service
adjustment.