With this type installation, the radius rods relieve the rear springs of the axle housing torque reactions on acceleration and braking. With the springs now virtually free of axle housing torque, rear axle steering movements will be free of torque influence.

Steering

PASSENGER CAR

Standard Steering

The steering system is modified to decrease steering effort and to provide geometry consistent with the increased wheelbase and increased vehicle weight.

Regular production models use a 24-to-1 ration steering gear, which when combined with changes in the linkage provides an overall steering ration of approximately 28-to-1.

Another feature of the steering system is the addition of a fabric-type universal joint in the steering shaft just above the steering gear (Fig. 4). The universal joint used in 1958 is still used near the dash panel.

The new universal joint is of the yoke and trunnion type, and never requires lubrication. The trunnion is a molded assembly of fabric laminations impregnated with rubber, so that angular deflection of the universal joint is provided by flexing the trunnion. Since steering torque is transmitted through the flexible trunnion, road vibrations and shocks are better isolated from the steering wheel.

Each of the three separated steering mainshafts is marked for steering gear high-point, and all of these marks must be place din alignment during service operations involving removal or replacement of these components.

Steering service operations are unaffected by these changes with the exception that the steering gear assembly is easier to remove for service operations.

Power Steering

The 20-to-1 steering gear ratio is retained for use with optional power-steering. Changes in the hydraulic system improve wheel return and provide smoother transition from manual to power assist.

A lip-type seal is used between the steering shaft and the steering gear housing, replacing the former garter-spring seal.

In the power cylinder, a synthetic composition piston ring replaced the cast iron rings previously used, resulting in a more efficient seal.

TRUCK

Power Steering

Power steering available on Series 70 and 80 models with 348 cubic inch engine, is the same system used on Series 90 and 100 models. Higher pump flow rate and increased power cylinder diameter reduces steering effort considerably.

Rear Axle

PASSENGER CAR

A new rear axle ratio of 3.08-to-1 is used with the 348 cubic inch engine with either Powerglide or Turboglide automatic transmission. The 3.36-to-1 rear axle ratio is continued for automatic transmissions used with either the 6-cyclinder engine or 283 cubic inch V-8's. The 3.36-to-1 axle is also used when 348 cubic inch V-8's are teamed with 3 and 4 speed transmissions.

The rear axle shafts are increased in length due to the increase in tread and the new brake construction.

With the exception of new axle shafts, axle shaft bearings retainers, axle housing and the new ratio hypoid gear set, most other rear axle part are interchangeable with the past models. Service procedures remain unchanged. Drive line angle specifications are revised to conform to the other chassis changes. A special shim is used under the propeller shaft mid-ship bearing support on air-suspension models.

TRUCK

15,000 Lb. Rear Axles

All 15,000 pound capacity rear axles provide better oil sealing and greater durability.

Both right and left handed differential side bearings for single speed axles, and left hand bearings for 2-speed axles have wider inner bearing races. The increased width provides larger contact area on the differential case, thereby preventing inner race rotation. Two-speed axles have induction hardened bearing seats on the left hand side of the differential support case.

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