Xk 120 steering issues

Chaps I’m still commissioning my 120 FHC following a total rebuild. I am experiencing a steering issue whereby if i f lift off the accelerator at speeds over 60 MPH the car become unstable, with me having to correct the straight line running. Its noticeable and quite scary.
The car is standard apart from fitting telescopic rear dampers with the correct (XK150) mountings top and bottom. The front alignment is all within spec although the castor is currently being increased to 5 degrees from the current 2. Tyres are blockley 185x 16inch Standard configuration wire wheels
Any similar experiences and solutions greatfull received.
Best regards.
Phil D

does it wobble, weave, or is it toward one side only (which) kinda evenly…
does it correct under power again? and then repeat when you lift, did you have this car driving before the rebuild and new parts? if so did it do any of this then?
meanwhile…I think I would follow the chassis / frame check procedure in the Manual…frame on even height blocks on a nice flat floor…drop some plumb line measurements to floor, mark, and measure carefully including the diagonals, to be sure chassis frame is straight, also that rear wheels are are straight aligned with the straight ahead (that the axle assembly is not somehow off square). just shots in dark…but a not too difficult check to eliminate those issues. Nick

Thanks Nick. Those checks are ongoing at this moment. Will report back

07714 759198

Hello Philip, you will remember I had a similar problem with my 120FHC.
Every time I lifted off the throttle at high acceleration the car veered sharply to the left. I found out it was the back end steering because there was a very small crack in the rear axle shaft cover outside but near the diff.
The back axle was moving at the crack. CKL welded it up, then put it on their axle measuring equipment and also found a huge amount of shims in the front steering suspension. They showed me the amount and said they had never seen so many !

Hello Philip, also still waiting for you to come up to Purley to see the new Man Cave !

Haven’t forgotten John. We are keen to come over. Let me get back to you soon

07714 759198

I had something like this on a Land Rover . It was loose U bolts on rear springs to axle .
Jim

as others said…maybe, something in the rear end loose that moves under forces.and back when rear wheels are not “pushing”: and while you are at the measurements/alignments do a check that the ride height is close to spec, but mainly the same side to side at front side frames, via torsion bar adjustments. Nick

update from today. i have used poly bushes on almlost all of the front suspension. on the front where the lower wishbone connects to the torsion bar the tube inside the polybush is not the correct length.so not letting the joint compress fully (bad description) under load that joint is moving around. This is soo much easier to see up on a 4 post lift as opposed to me rolling around on my garage floor!. the garage will get everything back together for a road test on Monday. i have also asked for them to check the TB settings using corner weights. the rear all looks fine.
I’m hoping things will be ok and i can get the car back early next week. ill post some photos when i get them from the garage guys.
Best regards
Phil D.

latest update following the front bush issue is…the rear axle. one of the tubes (diff to wheel) is loose. the plug weld has failed. unfortunately i cannot upload the video. should be back together tomorrow so we shall see if its all now fixed.