1979 W123 steering wheel in 1983 model?

[MagicBus]

Hello, all

I'm deep into my long-term (2.5 years and counting) 1983 240D build. I'm expending a lot more effort on this car than I ever thought I would.

Long story short, I'm fixing up a previously beat (looking more respectable by the day) 1983 240D. Last year, I bought and stripped a '79 240D for parts.

The 1983 steering wheel is pretty worn. My big concern is that the foam is separating from the core material. The simplest solution is to replace the steering wheel.

I saved the very nice earlier-style '79 wheel and was going to use that. I finally got around to trying to install it this week and made a discovery (well, a discovery for me, anyway). The '79 wheel mounts to the steering column with a large (22 mm?) nut. The '83 wheel uses a large bolt with a tapered head.

The '79 wheel sits on the steering column just fine. The splines are the same. However, I can't use the original '79 mounting nut, and although the '83 bolt does thread in, there's no provision for the '83 bolt to grab the '79 steering wheel (the '83 wheel had a dished indentation in which the tapered head bolt would sit).

For now, I re-mounted the old '83 wheel. Would it be safe for me to locate a new bolt (proper grade and size, but with a flat head) and use that to mount the '79 wheel in the car?

I could always locate a 3rd steering wheel, but the '79 one I have is nice, and I'd like to use it if it can be done simply and safely.