Steering Boxes

Excerpt from Basic Auto Repair Manual No.3, published by Motor Trend/Petersen Publishing Co., 1971:

• STEERING BOXES
• WORM AND SECTOR, WORM AND WHEEL DESIGN
• ROSS STEERING
• WORM AND ROLLER
• RECIRCULATING-BALL STEERING GEAR
• RACK AND PINION STEERING
• MAINTENANCE
• GEMMER WORM AND ROLLER
• RECIRCULATING-BALL ADJUSTMENTS
• REMOVING THE STEERING BOX AND COLUMN
• STEERING WHEEL REMOVAL
• POWER STEERING HYDRAULIC PUMPS
• POWER STEERING REPAIR

Steering Boxes

With cross-shaft cover removed, the sector and worm in this Saginaw steering box are exposed.


This Corvette steering box is similar to other Chevy boxes, but the adjuster plug is at the opposite end of the box.

Think back, if you can, to your first hot rod, not you'd first car, but the "soap box" racer you built from scrap wood and some "borrowed" baby carriage wheels. Steering was no problem. Right? you made the 2x4 front axle pivot on a bolt at the front of the “frame” and steering was just a matter of putting your feet on the ends of the axles; or if you wanted to keep your feet in, you shortened your mother's clothesline and used the rope to steer. It seemed logical enough at the time; after all, didn't all those wagons in the cowboy movies steer something like that? Thankfully, steering gear design has progressed steadily since those wagons went out of favor and “the horseless contraption” was invented.

Faster cars required better handling for those poor roads. And when "balloon" tires and front-wheel brakes were introduced, steering became even harder, and led to the development of the steering box. Essentially, the driver steered a wheel at one end of a shaft, at the other end of which was a set of gears that transferred the motion, through arms and rods, to the wheels.

WORM AND SECTOR, WORM AND WHEEL DESIGN

The worm and wheel was one of the first automotive steering gear designs. It proved to be inefficient, however, as all the friction was concentrated in the mesh area.

 

A variation of the worm and wheel is the worm and sector which was cheaper and could be built as a more compact unit.

The worm gear was, and still is, almost universal in its use on the steering column shaft. In the worm and wheel design, as the name implies, a toothed wheel meshed with the teeth on the worm, and a shaft connected this wheel with the pitman arm. The worm and sector was simply the same system, but instead of using a wheel, just a piece-of-pipe portion of the wheel was used, since within the turning limits of the front wheels most of the wheel-gear could not be utilized.

Friction proved to be the common enemy of all steering designs, and these early types were no exceptions. Most of the loads in the box were concentrated on the gears at their mesh points, and constant lubrication was a necessary drawback. They also required frequent adjustment, and proper alignment became difficult at the mesh point because it was found that the gears wore unevenly. That is, they most often wore out in the straight-ahead position, where they received the most use.

Once the gears were worn, you could adjust them only so much before the gears would bind. The worm and wheel type did at least have the advantage that the wheel could be removed and reinstalled with fresh teeth at the mesh point.

ROSS STEERING

This is the type in the SPL-311 before serial #25001 and the SRL-311 before serial #09001.

The introduction in 1923 of the Ross cam and lever steering gear was a solid step forward in terms of reduced friction and wear. One long groove (the cam) spiraled around the end of the steering shaft and a lever on the pitman shrift had a peg on it that fit this groove. As the steering wheel was turned, the peg was forced to ride up or down the shaft in the groove, and this action turned the pitman shaft and arm.

The Ross steering was a very good compromise; it was almost irreversible. It was difficult for motion to be passed from the wheels back up through the steering wheel, but enough was felt at the wheel to give the driver that important "feel of the road" which gives him confidence in his control.

WORM AND ROLLER

Originally introduced in 1926, the worm and roller configuration has proved so efficient that it is still being used today.

Friction was still a factor to be reckoned with, though, as cars got heavier, tires got bigger and tire pressures became lower for a better ride. It wasn't just that it was becoming harder to steer the car, but friction and wear within the gearbox was increasing again with these greater loads. So the people over at the Saginaw Steering Division of General Motors started making worm and roller steering in 1926 for the heavy Cadillacs. Basically, the worm on the steering shaft was hourglass shaped; it was thicker at the ends than in the middle. Instead of a curved sector meshing with it, there was a roller, like a single large gear tooth, which was perpendicular to the steering shaft. It was mounted in roller bearings in a yoke that was part of the pitman arm shaft. These bearings took much of the load and the big roller distributed the wear more evenly. The design was so efficient that it is still used today.

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RECIRCULATING-BALL STEERING GEAR

This is the type in the SPL-311 after serial #25001 and the SRL-311 after serial #09001.

By far the most widely used steering gear today it the recirculating-ball type, introduced on the 1940 Cadillac. Another development by Saginaw, it was basically an improvement of the screw-and-nut design that had been around for many years. A long worm gear was on the bottom of the steering shaft, on which a large, coarse-threaded nut was fitted. The nut was inside a collar or sleeve that could slide back and forth inside the box, and this sleeve had teeth on one side that meshed with a sector gear on the pitman shaft. As the steering shaft was turned, the nut moved up and down the worm gear threads and pushed the sleeve up and down with it, so that the teeth on the sleeve moved the sector and turned the pitman arm.

Actually, it was a let less complicated than it sounds, and had a number of features that have appealed to later engineers. One of the best features was its irreversibility; only enough road feel came back through the steering for good control. And it considerably reduced the driver effort involved in steering even such boat anchors as the 16-cylinder Cadillacs on which it was used.

That old specter of friction is the area modern engineers have so improved on this basically good design, which is where the recirculating balls come in. The grooves in the worm and inside the nut were machined for ball bearings, so that, in a sense, the balls performed the function of threads and absorbed the steering gear loads and friction. As the car was steered to the right, the balls would circulate in one direction, and in the opposite direction during a left-hand turn. Two tubes connected four holes in the nut sleeve unit so that the balls could circulate over and over again and distribute the wear evenly among all of them.

Friction was reduced so much that steering was made much easier without having to slow down the gear ratio, which as we have said results in more lock-to-lock turns for the driver. Except for power steering, this represents the furthest advancement of steering gear design thus far, at least on domestic cars.

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RACK AND PINION STEERING

Rack and Pinion Steering

Across the Atlantic "river," car manufacturers through the years have utilized some of the same steering systems as we have, though the light weight and smaller size of their cars have permitted the use of generally faster steering ratios. Perhaps the most interesting and different design is the rack and pinion type, seldom found on American cars, but common on most foreign cars and many different kinds of racecars.

In this case the gear on the steering column is similar to the pinion gear in a differential-cut on an angle, and meshed with a steer bar (the rack) toothed on one side. The rack is mounted parallel to the front axle, and as the steering wheel is turned, it operates directly on the steering linkage without the use if a pitman arm or draglink. It's fast, simple to work on, and lightweight because it eliminates some of the usual linkage, which are the reasons it has been such a favorite on racecars and sports cars. Its one drawback is that it has very little inherent reversibility, but in a racing machine the driver isn't worried about comfort or parking ability and is usually interested in more feedback or road feel than the average driver. Rack and pinion steering is thus a natural. Its quick action has made it the standard system on most imported sports cars, which acre small and light, but hasn't found much favor with Detroit because it would require too much driver effort on our bigger and heavier cars. For passenger car installations a compromise is often made by using a shock absorber-type damper on the linkage to reduce the reversibility. Since the damper's action is proportional to the amount of force put on it, small road shocks (desirable road feel) can be felt throughout the steering, but fast, hard, driver-jerking bumps are dampened.

Currently, however, manual steering gears are made in three basic types. The Gemmer worm and Roller Gear was used on Chrysler Corp. cars until the end of 1961, and on American Ramblers to date. General Motors passenger cars and Rambler, except American, use the Saginaw Recirculating Ball. Chrysler Corp. cars, 1962 and up, have a recirculating-ball type, and so do Ford products. A seldom-used type is the Ross Cam and Lever, used on Jeep and pre-'61 Studebakers.

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MAINTENANCE

Removing Pitman Arm

In most cases, you won't have too many complaints about the steering gear on your car, mainly because modern steering systems are well designed and relatively trouble-free, and besides, you'll probably be spending all of your attention on good stuff like the engine and suspension. Taking care of your steering amounts to no more than checking periodically, keeping it full of grease or 90W oil, and making adjustments when necessary. Rarely will you ever want to rebuild a steering box. It would prove to be a pain in the bippy. Most guys are content to misfit their friendly/unfriendly neighborhood junkyard for a replacement unit if something goes seriously wrong with it. You could buy a good used steering box and column for what it would cost to replace even one of the gears in your present box with: a new factory unit. But, as with anything you buy used or from a wrecking yard, you have to be careful or you'll wind up spending good bucks for an item that later reveals itself to be pure mung.

This steering pitman arm was evidently shortened and welded. It is definitely not recommended that this practice be undertaken, but if it is deemed the only way out for you, make sure the welding is performed by no one but a highly skilled, certified welder.

If you do buy steering in a junkyard, check it over as carefully as you would select a used transmission, even to taking off the box cover and washing it with solvent so you can inspect the teeth on the gears. Inspect the box for defects, cracks, welds, etc., and if bit's still in a car, try it out to see if it binds or has any play in it. If you're getting one from another model or year than your own car, see how many turns it is from lock to lock so you can determine if it has the ratio you want.
Before you start thinking about throwing out your steering and replacing it, check into it thoroughly, and even before attacking your steering box, try to determine first if it isn't something else which may be affecting the handling or steering. Things like poor shocks, unbalanced wheels, a misaligned front end, bad wheel bearings, or improper tire pressure can produce the same symptoms as defective steering gear.

If everything else checks out, then inspect your tie-rod ends and idler arm's. As trouble-free and long lasting as these parts are, they wear out long before your steering box. Jack up the front end or put the car on a hoist and push up and down on the idler arm. If it's loose, pull it off and inspect it. Usually there is a bushing in the end that should be replaced. Tie-rod maintenance involves pushing up and down on the end of the tie-rod, checking for play just as with the idler arm. To remove them you may have to borrow a mechanic's "tuning fork" or "pickle fork," which is a heavy steel bar forked at the end. It's machined at an angle, like a wedge, so that you can put the fork between the tie-rod end and the steering arm. Hitting the end of the bar with a hammer forces the stud of the tie-rod end out of its socket in the steering arm. Above all, the most important thing to remember when doing any work on the front suspension or steering is to never leave out the cotter pins. The life you save definitely will be your own.

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GEMMER WORM AND ROLLER

The worm is in integral part of the steering shaft, being hour-glass shape, or concave in the middle. It is supported at both ends by tapered roller bearings. The cross-shaft has a triple roller (instead of a sector gear) which fits into the teeth of the worm. An adjustment screw in the cover permits cross-shaft end-play adjustment which determines play between roller and worm. The pitman arm is fastened with a master spline to the roller shaft by means of a large end nut.

Worm bearing adjustment: If adjustment is necessary, first disconnect the steering linkage from the pitman arm. To eliminate end-play in the steering shaft, loosen the four end cover plate screws, then loosen the cover plate and separate the shims with a knife (be careful not to damage the shims). Remove one shim at a time, retighten the screws, and check for end-play by turning the steering wheel full right and left. Repeat this procedure until there is no end-play and no noticeable tightness in the wheel movement to full right and left. Retighten all four screws. Then check bearing pre-load with a spring scale on the rim of the steering wheel. If the pull is less than 1 1/2 pounds, remove another shim and repeat operation. If the pull is more than 1 1/2 pounds, add shims to decrease pre-load until satisfactory. Be sure all screws are tight when testing with the spring scale.

Cross-shaft adjustment: Loosen the cross-shaft adjusting screw lock nut in the cover. With the steering wheel in center position, tighten the adjustment screw slightly. Check amount of endplay by grasping the pitman arm. When end-play has been removed, use spring scale again on the steering wheel rim; if there is more than a 1-pound pull above the first scale reading, loosen the adjustment screw slightly. Caution: Do not overtighten. The steering wheel should turn freely from one extreme to the other without binding or stiffness. When satisfied, tighten lock nut on adjusting screw. Recheck with scale.

Then fill the steering wheel box with proper lubricant. Reconnect the pitman arm to steering linkage, and recheck front wheel toe-in; adjust if necessary.

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RECIRCULATING-BALL ADJUSTMENTS

 

This end view of a steering box shows the adjuster screw (on the right) with lock nut that allows lash adjustment of the pitman shaft. When repairing a ball bearing-type steering gear, keep all parts free of any dirt.	Chevrolet steering boxes all feature recirculating steel balls which offer a low friction drive between the worm and nut.

Adjustments for the Roadster steering box are slightly different than shown here. The side view diagram shows an adjuster plug with lock nut, which our steering boxes do not have. They are adjusted by means of a series of shims with varying thickness placed under the rear housing cover (next to the steering rod u-joint). You can tell if you need shims by the way it feels. With the steering box unlinked from the steering gear you should be able to easily turn the steering shaft with your fingers (where the u-joint connects). If you can't or it seems to catch at points or doesn't turn freely a shim or two is probably in order. Slightly loosen the three bolts which hold on the rear cover and see if that helps. If it does, get some shims. The adjusting screw on the top of the steering box works just the same as shown here though.

I recently got three of the shims (out of four sizes) in for my steering box. Here are the Nissan part numbers:

For the late-model crowd, here's the "skinny" on adjusting the recirculating-ball steering. Here you have only two adjustments to make for end-play on each of the shafts. You won't have to worry about worm/nut mesh because the use of the steel balls between the teeth eliminates wear in most cases. Jerking up the car and disconnecting the pitman arm from the linkage is still the first step. Remember, when working on this type of steering system when the linkage is off, don't turn the steering wheel hard over to either extreme or you may damage the steel balls. If you suspect that the car may have been in a front-end collision at one time, then loosen the steering column support mount that is under or behind the dashboard to eliminate this possibility of a misaligned shaft during the adjustments. If your car has flexible U-joints in the steering shaft, you don't have to worry about this.

With the steering about one turn from the full left or full right, back off the locknut on the pitman shaft (opposite side of box from pitman arm) and loosen the adjustor a few turns counterclockwise to take the mesh load off the gears. Now pull up and down on the steering wheel to check for endplay in the steering shaft. Play can be taken out by another locknut/adjuster combination found at the bottom end of the steering box. The large locknut can be loosened by tapping it with a hammer and punch, in the notches provided, if you don't have a wrench that big. Always check for lost motion again after tightening the locknut following an adjustment.

Now you can adjust the end-play in the Pitman shaft and at the same time take care of lash where the sector gear meshes with the teeth on the underside of the ball-nut mechanism. Since the gears are cut at an angle, end-play adjustment of the postman shaft controls the mesh between them, too. Turning the adjuster clockwise will take up the lash, but make sure you don't over tighten it. These adjustments of late-model steering gears will only rarely be needed, but by all rights they should be made with the use of a pounds-pressure gauge on the steering wheel to measure drag or bind. Assuming that you don't have such a gauge, though, you can do it yourself a as outlined above, or have it done at your dealer's garage.

Lubrication for the steering box (about SAE 90W) can be purchased at most parts stores or you can have it a put in at a garage, since you don't need very much. Some steering boxes use chassis grease. If there is no filler plug on the box, or if it has a grease gun type lube fitting, it probably should have chassis grease. Using 90W in a box designed for chassis grease will result in a big mess because the 90W will probably leak out profusely.

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REMOVING THE STEERING BOX AND COLUMN

Dodge Collapsible Steering

If all of the above has failed to correct any problems you suspect are combing from the box, then you haven't much choice but to replace the unfit. It may look like it's going to be a beast of a job (it really isn't), but keep telling yourself that you need the exercise, or consider it as a challenge. Naturally, you first have to take that steering wheel off, and for this you're going to need a steering wheel puller or gear puller because it's on there pretty tight. You'll need it to pull the pitman arm from its shaft for the same reason. Before starting, determine if the gear and column can be removed from the top - by raising it up through the dash over the driver's seat - or by dropping it down through the floor or dash, beside the engine and out from below the car. If necessary to drop it out through the bottom, arrangements must be male to jack up the front end of the of to permit the removal of the gear and column assembly.

Once the removal route has been determined, here are the steps you should follow:

1. Place protective cover over the front seat.
2. Disconnect battery cables.
3. Disconnect wires at bottom of the steering column, one at a time and tag each wire carefully.
4. Disconnect steering linkage from pitman arm.
5. Remove jacket tube clamps at steering gear housing (if any).
6. Disengage steering shaft flange from flexible housing. Note: Some late cars have a flex connection between gear shaft and steering wheel shaft. This will make it unnecessary to disturb the steering column and wheel.
7. Remove support clamp at instrument panel.
8. Remove horn and signal wires from steering column below instrument panel.
9. Remove horn ring and steering wheel-a wheel puller is needed.
10. Remove dust shield at firewall.
11. Remove floor opening panel (if any exist).
12. If car has manual shift lever on steering column, disconnect gear shift rods at the bottom of the steering column.
13. Disconnect neutral safety switch wire at bottom of column and tag it.
14. Unfasten steering gear from the frame (attached with three or four bolts).
15. If car has automatic transmission, disconnect gear indicator from the dash dial.

After disconnecting the electrical and shift linkage connections from the mast jacket - which is the column or tube covering the steering shaft - you can unbolt the box from the frame, the mast jacket from the dash bracket, and pull the mast jacket into the inside of the car and off. The shift arms on it can be worked through the flexible sealing around the steering column at the firewalls Now the box itself and the steering shaft can be removed from the frame.

Because safety is so important, the collapsible steering column has become a standard item on new cars. Some have a steel mesh section in the middle that folds up in a crash, while later versions utilize two sections held together with plastic pins that shear under impact, telescoping the two sections. When working with such a column, be careful not to collapse it by accident (no pun intended). Don't yank on it too hard, and don't use a hammer on the shaft to loosen the steering wheel when removing it.

VW Collapsible Steering

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STEERING WHEEL REMOVAL

Removing Steering Wheel

To avoid breaking the finish on your steering wheel, always use a steering wheel puller should you have to pull the wheel.

The removal of the horn sounding ring or button can sometimes be more difficult and perplexing than the removal of the steering wheel. One of the cardinal rules of the good mechanic is: Never use force to remove units or parts, unless you know how. Forcing in the wrong place can lead to damage or breakage, and can cost embarrassment, time, and money.

To remove the horn switch or steering wheel, first disconnect the battery to prevent the horn from sounding. In all cases a wheel puller should be used to remove the steering wheel. Before removing the wheel, make a scribe mark on the end of the steering wheel shaft and own the wheel hub, so the wheel can be reinstalled correctly. Some cars have a blind spline for this purpose.

 

POWER STEERING HYDRAULIC PUMPS

This view is of a Saginaw power steering gear box. The light gray areas are filler with fluid, and since the unit is shown under straight-ahead operation, the oil pressure in the box is low.

As with most power steering pumps, maintenance and service of such units is touchy and should be left to highly qualified personnel.

This roller-type power steering pump is commonly seen on the products of Chrysler Corp.

Many modern cars are equipped with power steering, which includes two basic units: the hydraulic oil pump and the steering unit. The hydraulic pump is engine driven and supplies oil pressure as needed to the steering unfit. It is usually belt driven and mounted at the front of the engine.

All power steering pumps are constant-displacement type, delivering from 650 to 1300 pounds pressure, depending upon the type and make of the system and the car. Special power steering fluid or Type "A" automatic transmission fluid is used. This fluid is stored in a reservoir attached to the pump with a filter in the reservoir to prevent foreign matters from entering the system. The pressure relief valve located in the pump prevents the fluid pressure from exceeding the predetermined maximum pressure of the system. Flexible hoses carry the fluid to the control valve of the steering unit. The smallest or high-pressure hose carries the fluid to the control valve of the steering unit. The larger of the two hoses is the return, or low-pressure hose. A flow control valve is combined with the pressure relief valve located inside the pump.

When the fluid circulation reaches about 2 gallons per minute, the flow control valve is forced to open a passage between the inlet and outlet sides of the pump, and all excess oil is sent back to the intake side of the pump and recirculates through the pump. When oil pressure exceeds the fixed pressure limit, the relief valve opens and allows fluid to flow back to the inlet side and recirculate in the pump without raising the pressure in the rest of the system.

There are five types of pumps in use: vane, rotor, roller, sleeve, and slipper. Detailed information for the pump concerned can be found in the shop service manual of the particular car make and model.

Before any major service operations are started, the following items should be checked and corrected.

Low fluid level is a source of many power steering ills, including poor power assist, excess pump noise.	Follow instructions. The dipstick on this power steering unit states clearly that you should check the level of its reservoir only when the oil is hot.

Fluid level: Check level at regular intervals. Wipe the cover before opening to prevent dirt getting into the system. Maintain fluid level 1 inch below the top. If fluid is very low, check system for leaks. If only a small amount of fluid is needed, automatic transmission fluid can be used. When using larger amounts or changing fluid it is advisable to use special power steering fluid. Oil should be at operating temperature, wheels in a straight ahead position, and the engine stopped when you check or add power steering fluid.

Testing Belt Tension

Belt tension and condition: Belt tension should be maintained between 60 and 90 pounds (for a new belt). If a belt tension gauge is not available, the deflecting of approximately 1 inch in the middle of the the belt pulleys, with a medium pressure of the hand, is too loose, and the tension should be tightened. Caution: the use of a pry bar can damage the pump or reservoir. Check the belt for evidence of age and wear. Frayed edges, separation of the layers of the fabric (look at the side of the belt), and cracks on the inside of the belt indicate age and brittleness. The application of a good belt dressing will reduce slipping and noise.

Proper lubrication and condition of steering linkage and front suspension: The steering gear, linkage, and front end should be serviced, lubricated, and alignment checked before any major work is attempted on the pump. Check tires for correct air pressure. Steering effort can be checked with a spring scale, with engine idling and front wheels on a smooth floor or driveway. Attach a spring scale to the rim of the steering wheel; as you turn the wheels from one extreme to the other, the pull should not exceed 10 pounds at any point.

Oil flow and relief valve operation: You can check these valves by turning steering wheel full right or left, with the engine idling. if these valves are working, a slight buzzing noise can be heard. Caution: Do not hold the wheel in this extreme position for more than 2 or 3 seconds. If the relief valve is not working the high pressure might damage the system. If no buzzing noise can be heard, a sticking or malfunctioning valve is suspected. The use of power steering additive, found at most auto supply stores, will clear up many of your power steering problems.

 

POWER STEERING REPAIR

Because the modern power steering unit is a precise piece of engineering, and due to the requirement of a number of special tools, we cannot recommend that the beginning mechanic tackle this job outside of a completely equipped shop with the help of qualified professionals. If any of the faults mentioned above occur and the indicated repair consists of more than linkage replacement, belt tightening, or the use of an additive, take the vehicle to a qualified professional. Do not attempt to do it yourself. On some earlier models of the mid-1950 period, the power steering unit is an "assist" or linkage type and can not be replaced without removing the entire assembly. On others the unit is coaxial (Chrysler) or otherwise integral with the gearbox. In every case than simple external mechanical adjustments, take the car a professional since most power repairs are beyond the scope of the corner gas station or the home garage.

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