Except for the changes described below, the rear axle assembly and drive line for 1958 re­ main the same as the 1957 after jobs.

A longer radius rod is used in 1958 to give better control over rear end motion, and the radius rod bracket on the rear axle housing has been relocated farther outboard. Provision is made for lubrication of the rear propeller shaft rear coupling. Two rear axle housings are used, one for coil spring and the other for air ride suspension. They are basically the same except for brackets.

NOTE: An economy axle ratio of 3.07 will be offered as optional equipment on cars equipped with Dynaflow transmission.




  1. Jack up car at center of axle housing and place floor stands under frame side rails.
  2. Lower jack and allow axle assembly to lower close to a full rebound position.
  3. Disconnect height control valve links at the height control valve levers using YI 6″ wrench.
  4. To prevent damage to air spring assemblies, carefully and slowly loosen air lines at spring domes. This will exhaust all air from rear air springs.
  5. Remove two bolts retaining plunger bearing plate to rear axle housing and pull plunger down and away from diaphragm plug. Remove plunger and bearing plate assembly.
  6. Disconnect radius rod at axle end using 3/4″ wrench and 9/16″ deep socket.

CAUTION: Never disconnect radius rod or torque tube unless all air is exhausted from rear air springs.

  1. Disconnect lower ends of rear shock absorbers using 5/8″ wrench.
  2. Disconnect parking brake cable at rear cable sheave and at bracket on torque tube. Disconnect brake hose from pipe at frame X member and retaining clip yoke. Cover hose and pipe to prevent entrance of dirt. Loosen torque ball bolts.
  3. Remove two opposite torque tube flange bolts, replacing them with two 3″ guide pins. Remove remaining torque tube flange bolts using 9/16″ socket.
  4. Lower axle assembly and push rearward to clear torque ball.
  5. Roll rear axle assembly out from under car.


  1. Roll rear axle assembly under car and align as close as possible.
  2. Place floor jack under center of housing and raise to required height.
  3. With 3″ guide pins in place, align and connect torque tube to torque ball, making certain that blank splines on propeller shaft line up with those in rear yoke of universal joint. Remove guide pins and install remaining two bolts.
  4. Install parking brake cable. Connect brake hose to pipe and secure with yoke at frame X member. Bleed rear brakes and adjust parking brake cable.
  5. Loosely connect radius rod and shock absorbers.
  6. Connect air lines to rear air spring domes.
  7. Insert plungers into air springs, and in­ stall bearing plate to axle housing. Carefully pull down on height control valve lever to partially inflate air spring assembly and retain plunger.
  8. CAUTION: Never move rear height control valve levers manually more than 1″ in either direction from a neutral position, measured at end of lever as internal damage could result which would affect the riding qualities of the car.
  9. Connect height control valve links to height control valve levers.
  10. Tighten shock absorber bolts and radius rod bolts.
  11. Raise car with jack, tighten radius rod and shock absorber mountings, and remove floor stands under frame side rails. Lower car to floor.
    NOTE : Shock absorber to bracket bolts must be torqued to 60-80 ft. lb.



Provision has been made to lubricate the rear coupling of the rear propeller shaft where it joins the shaft to the pinion shaft. To lubricate this fitting, proceed as follows:

  1. With car on hoist, transmission in Neutral and parking brake released, remove plug located near bottom of rear torque tube, just for­ ward of large section of tube.
  2. Hold one parking brake cable and rotate opposite rear wheel until lubrication fitting appears in hole in torque tube.
  3. Lubricate fitting with % to 1 oz. of chassis l u be (one quick shot with lube gun).
  4. Install plug and lower car.

NOTE : Fitting should be lubricated every 1,000 miles during regular Lubricare.