Looking for some "expert" advice on steering boxes...or some new ideas

What would be the symptoms of bad bearings in the steeering box?

Here is the question-I have an annoying left to right shake in the steering column at 40-50MPH only, mostly at 45MPH- really more of a wobble and shake then a true vibration...

At speeds below fine and speeds above, rides dead straight-no wobble or shake. Crusing at 65-70MPG car rides awesome, smooth and straight. I have tried all the typical culprits...all new front end, new idler arm pitman arm, rebalanced the driveshaft (new u-joints installed), new shocks, new tires. Tires rebalanced several times, even on new Road force machine,under load. car is convertible with 327 engine with PG trans. Normal steering from left to right (turning) is smooth and easy(no rough spots or tightness)

Some one said that perhaps the bearings in the steering box are bad and at that one speed range is causing the left to right wobble feeling in the column?

I should note that the steering box and rag joint were not replaced when the new front end was done (both seemed ok-if doing over again would have just replaced both). Should also note, that if I put the car in neutral when cruising down from 65MPH - when the car passes through 45 mph to 40mph wobble present in column, then goes away below 40mph? I would think that eliminates bad, trans, rear, or driveshaft?

Any ideas?

If anyone knows anyone who rebuilds steering boxes please let me know...

thanks!
JL

Bearings are in the front and rear of the box. You have a worm type gear with a set of bearings in roller cage. I believe these fit into the driven pitman shaft. Those are the ones that could be causing problems. You have replaced everything else including replacing some tie rod ends? You did not state this. As for the rag joint, that pretty simple , its either tight or not , this can visible. This almost sounds like an old Ford issue where the king pins were worn out but you dont have those. These ps and manual gear boxes are available as rebuilt items thru most parts stores. You did not indicate how much play was in the steering box, ie dead still, left to right. If matching numbers is not an issue here, perhaps you should look into these. If you find an old shop manual or Chiltons manual, you can look this up and see how they are made and what I am referring to. I am not an expert. You may even do a search at David Pozzi's site or this site.

Yes all new tie rods and adjusting sleeves...were used with front end overhaul.

Sorry to hear about your vehicle vibration. To diagnose the problem it would be helpful to know a bit more about the car.

What I am getting from your description is that the vibration is felt in the steering wheel and not so much in the seat of the pants. Also that it is a lower frequency vibration than would be expected from a driveshaft. In the event that it was a driveline vibration, you would feel it more in the seat and it would be a very predictable high frequency vibration at a certain speed. Direction, road variation and steering input would not change it. You would not get a steering wheel shimmy in this case.

Assuming it is a steering wheel shimmy issue, it would be good to know what changes the vibration to understand where it is coming from. For instance, can you eliminate it be stabbing the brakes? Will road variation make it better or worse? Does it diminish when going around a curve? Have you substituted a known good set of tires from a buddy's car on the front end to rule out tire issues?

I am wondering about the looseness you describe in the steering. there is a pre-load adjustment that should be performed if you have excessive looseness in the steering gear. It is controlled by the locknut and screw on the faceplate of the steering box. Careful not to make it too tight, so an experienced technician would be best to make this adjustment.

I am also wondering about any looseness in the front end. If you were to raise the front wheels and grasp the tires and try to wiggle them back and forth, would you notice any movement or loseness in any of the joints such as the idler arm.

Another thing to check is the radial (straight out from the center axis) and lateral (perpendicular) run-out of the wheel hubs, wheels and tires.

Lastly, the alignment specs. Too little caster will cause the front end to wander while driving and be less stable. Too much toe-in will also make the steering less stable, toe-out will stabilize the steering, but careful- this is a tire wearing angle.

Just a few thoughts. Let me know how things come out.