If your trying to align the top bolt try a medium Philips screwdriver down from above and turn stub slowly from lock to lock. You can feel the kingpin and drilled threaded hole. Slight movements of the stub will align it. Sometimes, as you found, they go straight in and sometimes they need a tweak.
I used to use a long threaded bolt and nut through the top to remove and refit to compress the spring and I machined a tapered lead on it and this had the combined effect of not only making it easy to start the thread but it also centralise the pin, just a long tapered lead kind of thing.
If your struggling and close to Solihull it’s in my toolbox if you want to borrow it?
BR
Colin
