I will assume it is very similar to the 123/126...IE no rack and pinion. There is a large 19mm nut on top which locks down the adjuster which is a 6 or 8mm allen. Spray them with penetrating oil, then crack loose the large nut and carefully work the allen bolt loose from the large nut. Turn the allen counterclockwise until you begin to feel resistance in turning the steering wheel off dead center, then back it off a bit and lock it down with the large nut. Try the car and tighten or loosen to your taste. Its pretty simple but take your time with the allen and lock nuts as they can be fairly tight.

The steering boxes can be adjusted successfully with well over 300K on the chassis.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.