Hissing Noise In Steering Gear - Jeep J-10 Series 1982 Technical & Service Manual

2L-6 POWER STEERING GEAR AND PUMP
Variable Ratio Power Steering
A variable ratio power steering gear is used on Chero
kee, Wagoneer and Truck models. CJ and Scrambler
modelsare equipped with a constant ratio steering gear.
The ratio of a steering gear is the relationship of
steering wheel movement to that of the front wheels. It
is described in terms of the number of degrees of steer
ing wheel rotation required to turn the front wheels one
degree.
Variable ratio steering is accomplished by using a
pitman shaft sector that has one long center tooth
flanked by two short sector teeth. This is opposed to a
constant ratio gear where all sector teeth are of equal
length (fig. 2L-5). Because the variable ratio gear has
unequal length sector teeth, companion changes are also
made in the rack piston teeth (fig. 2L-5).
CONSTANT RATIO
VARIABLE RATIO
AJ41064
Fig. 2L-5 Rack and Sector Comparison
Since the sector is basically a series of levers, any
movement of the rack piston causes the sector to swing
the pitman arm in the same ratio. In other words, it
turns the pitman arm the same number of degrees with
each sector tooth.
To increase or decrease steering ratio, it is only neces
sary to change the length of the sector teeth. A low
numerical ratio (smaller radius sector with shorter
teeth) produces greater pitman arm movement than
would a high ratio sector with longer teeth and greater
leverage.
On this basis, the variable ratio sector is in reality one
long, high ratio lever at the center, flanked by two lower
ratio levers for left and right turns.
In the straight-ahead position, only the tip of the long
center tooth is in contact with the rack piston. As a
result, initial movement of the rack piston in either
direction produces a relatively small response of the
sector and pitman arm. This is due to the high ratio
produced by a long lever relationship.
Because of this relationship, the steering ratio re
mains a nearly constant 16:1 for the first 40 degrees of
steering wheel movement in either direction from
center.
Turning the steering wheel further reduces the length
of the lever. This moves the point of contact down the
side of the center tooth decreasing the radius and pro
viding a steering ratio of 13:1 at full lock.
SERVICE DIAGNOSIS
When diagnosing suspected power steering system
malfunctions, refer to the Service Diagnosis Charts in
this section for probable causes and indicated repair
procedures.
To avoid ineffective or unneccessary repair, do no:
attempt to correct a malfunction until an accurate diag
nosis has been made. Utilize the diagnosis charts, hy
draulic pressure test and leak diagnosis procedures
before servicing the gear or pump.
Service Diagnosis—Steering Gear and Pump
Condition
Possible Cause
Correction
HISSING NOISE IN (1)
There is some noise in all power
(1)
Slight hiss is normal and does
STEERING GEAR
steering systems. One of the
most common is a hissing sound
most evident at standstill park
ing. There is no relationship
between this noise and per
formance of the steering. Hiss
may be expected when steer
ing wheel is at end of travel
or when slowly turning at
standstill.
not affect steering.
RATTLE OR CHUCKLE (1)
Gear loose on frame. (1)
Tighten gear-to-frame mounting
NOISE IN STEERING
bolts.
GEAR
60702A