C1 Steering Box Restoration - Restoring The C-1 Steering Gear

Straight Steer From A Vintage Worm-And-Roller Gear!

Moses Ludel Sep 9, 2009 0 Comment(s)
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Chevrolet engineering dominated the chassis and front suspension of the original Corvette while the steering and suspension designs came mostly from Chevrolet passenger cars. For the steering gear, Chevrolet drew on Saginaw Division's worm-and-roller unit, the standard fare for lighter G.M. cars of that period.

In 1940, Saginaw pioneered the revolutionary recirculating ball-and-nut steering gear. Heavyweight, upscale models like Cadillac, Buick, the Oldsmobile '98' and light trucks quickly benefited from the design. Chevrolet, Pontiac and lighter Oldsmobile models, however, continued to use Saginaw worm-and-roller gears. Less sophisticated, with fewer components, worm-and-roller gears were common to many postwar vehicles. Arguably, Chevrolet's first-generation Corvette might have benefited from a smoother, more precise recirculating ball-and-nut gear. A recirculating ball-and-nut gear offers closer tolerances, nimbler steering and a longer service life. Once again, the decision to use a worm-and-roller unit tied the Corvette to Chevrolet's 1953 passenger car models.

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Here is a prime incentive for rebuilding a C-1 steering gear. A previous owner stripped the steering wheel nut and threads on the steering shaft. Threads on the shaft are beyond repair, requiring replacement of the entire steering shaft and worm. Although the gear has only minor wear, a complete restoration is now practical.

By 1955, Chevrolet passenger cars dropped worm-and-roller steering gears, opting for Saginaw's recirculating ball-and-nut design. In defense of the C-1's worm-and-roller gear, the unit did offer greater stamina and better performance than the Gemmer gears used in '55-'57 Thunderbirds. More importantly, vintage racing Corvettes quickly proved their worth, and worm-and-roller steering carried through the C-1 era. Corvette did not acquire a recirculating ball-and-nut gear until 1963, being the last G.M. model to do so.

Design And Wear Points
A Corvette worm-and-roller steering gear has a ball-bearing supported roller gear. This is a plus, as the ball-bearings are rugged and generally outlast the life of the gear. The roller mounts at the inner end of a sector shaft, and the outer end of the shaft supports the pitman arm. A solid steering shaft has a worm gear at its base. The roller gear teeth engage the worm. As the steering wheel rotates the steering shaft and worm, the sector shaft pivots, rotating the pitman arm fore-and-aft.

The worm has tapered roller bearings at the top and bottom. This support is ample and provides many years of service. The upper end of the steering shaft rotates in a column bearing, which supports the steering wheel. An iron gear housing, needle roller bearing support for the sector shaft, and quality bearings on the roller make this gear reliable and rugged. By contrast, the Gemmer worm-and-roller gears use small needle bearings on the roller, and the sector shaft's support is two bronze bushings.

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The tale of damage began with the replacement of the turn signal switch. Use care when removing and installing the steering wheel. Cross threading the steering shaft threads is not only dangerous, it requires complete disassembly of the steering gear to remedy. This shaft has been ruined by careless workmanship.

Assuming a C-1's gear has proper lubrication, wear is predictable. Needle bearings, tapered roller bearings and ball-bearings will wear over time. Rarely is this wear so minimal as to allow for adjustment of the gear. However, adjustment can sometimes remediate minor looseness and provide additional service before the inevitable rebuild. If light adjustment can remove normal wear characteristics, and if the gear moves freely through its range of motion, an adjustment could be warranted.

More often, if you find that the sector or worm bearings require considerable adjustment, the gear definitely needs rebuilding. The roller teeth and worm can wear or pit, chip or corrode. Attempting to adjust out such play is dangerous. Overly tight, the worm-and-sector can bind or even lock up. Upon disassembly, the gear that requires appreciable adjustment will show sufficient wear for a rebuild.

Fortunately, unlike many other steering gears of the '53-'62 era, there are aftermarket rebuild parts available. Corvette America and Corvette Central offer an extraordinary rebuild kit for the C-1 steering gear. The kit is available for models with either '53-'57 or '58-'62 steering shaft lengths. A premium quality steering shaft and worm, a new roller with inner race and bearings, worm bearings, sector needle roller bearings, a sector shaft seal, cover gasket and upper column bearing with new horn wire round out the package.




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