I've just changed both kingpins on my red 2cv. After I changed the second one, I noticed that the steering wheel was in a different place when the car was going straight ahead. It hadn't changed after I did the first kingpin, and I've not adjusted the tracking at all. Everything went back together just fine, the wheels seem to be in line with each other and the car is driving perfectly (much much better than before - as the old pins were really bad).

Why has this happened?

when you say a different place....

Seems quite straightforward that the second kingpin had enough play in it that it was effecting the tracking on that wheel. Although the difference isn't visible by eye, I suspect that if you had measured the toe in/out before and after you'd be able to see the difference.

your MOT man is "good" Jono! lol...

Not sure why changing the pins would result in the go straight being in a different position? odd!
Was the entire front end in the air when doing the pins or just a side at a time? is everything else tight and as it should be? TRE's, steering column bottom U clamp, axel/arm bearings?
I take it from your FB comment you left the arms and steering on and complete when doing the swap and only changed the king pins?
check your tracking with string, sticks and biscuit tins and see if there is anything that looks off, i cant imagine that the pins were so worn you didnt notice the tracking wandering a mile out!

isnt there a roll forward, roll backwards test you can do to see if the wheels toe in and out correctly? (Ken?)

Jono,
I'd reckon that Joolz is on the right track, so to speak.

If you let us know which side was replaced most recently and also in which direction the steering wheel has moved?

Must have been plenty of play in that kingpin, btw...

ken

On second thoughts the difference in tracking might not be evident when stationary. Perhaps it's only when driving that the 'slack' in the kingpin is taken up, and the tracking effected.

Yeah, that's what I was thinking/hoping it would be. The old pins really were bad - my MOT man let them go as long as I changed them soon. He's good like that

I changed the left one first, (which made no difference to the steering wheel's position), and today I did the right one, and the straight ahead position on the steering wheel then moved from 6 o'clock to about 5 o'clock.

b#gg@r,
that's another theory out of the window...

Suggesting that play in the righthand side pin was allowing the wheel to toe in when driving, which is what I would expect in a fwd car, am I not right?