Ball Nut & Worm Shaft Assembly

1980 Chevrolet Forward Control 5.7L Eng VIN M, Automatic Trans, Trans Mfr CD 400/M40SECTION Ball Nut & Worm Shaft Assembly

Ball nut disassembly is not necessary unless there is indication of binding or tightness when rotating worm. If disassembly is required, proceed as follows:

  1. This first step is going to let loose about 50 ball bearings; be ready to catch them ALL. Remove clamp that retains ball guides and pull guides from ball nut while catching balls in clean pan. Turn nut over and rotate worm until all balls have fallen into pan. Remove worm from ball nut. Wash parts and inspect worm, nut grooves, and ball bearings for indentations. Check ball guides for damage at ends where they deflect or pick up balls from helical path on worm.
    Fig 1: Removing Worm Shaft Bearing Race on Sector Shaft Gear
    G09318752Courtesy of NOT AVAILABLE
  2. To reassemble ball nut and worm shaft, insert ball nut over worm so that the shallow end of the ball nut teeth are on left side when looking from steering wheel end of worm shaft.
Fig 2: Exploded View of Recirculating Ball Steering Gear (General Motors Model Shown)
G09318753Courtesy of NOT AVAILABLE

Align grooves in worm and nut by sighting through ball guide holes. There are two types of ball guides: ones with holes in middle, and ones with no hole. If ball guides have hole in middle, insert ball guides into holes in ball nut. Divide balls into two equal groups and insert each group into a ball guide while slowly turning worm shaft. If guides have no hole, separate the halves and fill one-half of each set with balls. Cover filled half with other half and plug ends with lubricant so that balls do not fall out. Fill each circuit in ball nut with half of remaining balls in one circuit, and half in the other while slowly turning worm shaft. Insert ball guides. On both types, install ball guide retainer.

Fig 3: Filling Ball Circuits Through Holes in Ball Guides
G09318754Courtesy of NOT AVAILABLE
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.