Re: Looking for the improved TR3 steering box cove
After 60,000 miles, the amount of wear on the sloped sidewalls of the groove in the worm, plus wear on the pin that fits into this groove, will cause this wandering effect. Mine was like that. If you dismantle the steering box, you can rotate the tapered pin by 90 degrees to the point where it is no longer worn on the tapered sides where it sits in the groove of the worm.
About 95% of the steering takes place by small corrections on straight (or almost straight) roads. That's why these wear at the center. Tightening down the original peg to prevent this means that the peg is down too far (hence too tight) near the extreme locks of the turning circle.
After putting in the spring-loaded peg in my steering box, it has been fine for the last 90,000 miles. I had to re-adjust the new peg twice during those 16 years. It tracks like it did when new.
The spring-loaded pin in the improved design is tightened down to the point where it is just tight at the center. This eliminates the wander. At the extreme locks where the original one it gets tighter, the spring compresses and it doesn't get tighter.
No TRA concours judge ever docked me points because they can't see it. It is concealed behind the air deflector panel that surrounds the radiator.