James, it appears that a previous owner may have assembled the kingpin top bolt incorrectly. Since it needs to be removed anyway to add brake reaction bars (BRB) can I suggest you slightly loosen both top and bottom kingpin fixings before removing this top bolt completely, noting the position of the matching pair of concave and convex washers that fit within each other immediately underneath. Hopefully you will prove this is not cross threaded.

Given the year of your car it will have factory adjustable camber whereby the curved upper end of kingpin sits in a cup formed in the underneath of top support arm and a laterally sliding lug controlled by threaded stud and locknuts at the lower kingpin mount allows pivoting of same to achieve camber change. I mention this because it's relevant to the top kingpin bolt angle hence the dual washers which fit within each other to accomodate this angle dependant on camber setting when tightening down kingpin bolt. Suggest you also loosen the nut/bolt that secures the wing mount to the upper shock absorber plate. This should allow some movement of same which hopefully may ease the fitting affecting the addition of BRB. Worst case remove wing bracket and file corner off although this is not normally necessary.

When each BRB is in position with chassis end loosely tightened and kingpin end resting on upper shock plate the kingpin bolt can be fitted with washer pair located through same, BRB, shock plate, upper suspension mount hole and finally hand started to engage with threads within kingpin below - beware of cross threading! Note the washer pair are formed by convex and concave sides fitting within each other, former at the top and flat sides facing outwards - important they fit immediately below bolt and are well greased. If difficulty found in hand engaging bolt into kingpin threads, loosening lower kingpin nut and even the camber plate will help in allowing kingpin to pivot to a better angle. In the latter case reset camber to noted position on threaded studs before re-tightening everything that was loosened, kingpin bolt first. Note also alignment of grease nipples within bolt. I usually have them facing forwards and slightly outwards for easiest grease gun attachment. If this is seemingly not possible to achieve the whole kingpin can be twisted with lower nut slightly loosened.

When assembled correctly it should look like this, noting the ends of my wing brackets are rounded ex factory.

[Linked Image]


Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone