Power Steering Strength Adjustment
 

I have two W123 300D turbos and they both have very different steering characteristics. One, 1984, has a heavy wheel with a little free play where the other one, 1983, is really easy to turn and also has too much free play. They both have good steering dampers because I've replaced both in the last couple thousand miles.

Is there a way to adjust the power steering assist on these cars? I don't like the '83 because it is sloppy and too easy to turn the wheel. I need to adjust the play on the box, but would that also tone down the assist strength?

Thanks,

There is an adjustment screw (with locknut) on the top of the gear box. CW loosens, CCW tightens.

adjusting requires two people.. you.. and a helper

Adjusting slack is one thing, power assist is not adjustable.

That's absolutely correct. You are actually changing the power required, not the power available.

I don't know the reason, but there is a big difference between my two 84's. Steering on the 300D is a bit heavier than what I would consider ideal. Steering on the 240D is very light, much more pleasant to steer.

Probably the 100lbs difference over the front end.

Might be a difference in caster as well but I don't know if a couple of degrees difference would be a dramatic change in steering effort.

There is quite a noticable difference. I don't think 100 pounds would account for it.

There may be some alignment issues with the 240D. The 300D was aligned a while back, and the alignment seems good. No unusual tire wear or anything. The 240D front end is close to needing a rebuild, although the steering play is practically zero.

I have noticed that tire size, tire pressure, and alignment do make a noticeable difference in feel. My 240D (with 175 tires) does feel "lighter" than my 300D with 205 tires.

Same Michelins at the same pressure on both cars. But I know what you mean though. The previous tires on the 300D were Bridgestones, and they had a heavier feel, as if the pressure was low.

Tire difference.
 

When I switched from Dunlops to Michelins, the SDL became a lot easier to turn. It was like the front end was lighter. And, I had 33 lbs in both sets of tires.

I had an indie shop do the alignments on both cars within the last year. I should go through the records and see if he changed the caster.

Is there constant pressure in the power steering supply line from the pump, or does the pressure vary with an increase when the wheel is turned and the box requires power?