Upper Ball Pin Not Fully Seated - Mark V

Pre-XK
1

Hi folks, on the Mark V front upper ball pin C.3031 (VA.4), I’ve fitted new assembly on LH side, that goes snug. On the RH side the upper ball pin goes in and when the retaining nut is snugged up then the nut and ball pin will rotate about ten degrees relative to the RH Stub Axle Carrier C.3009 (VA.1) during full steering rotation of the RH brake assembly.

I’ve tried putting a washer under the nylock nut in hopes of pulling it a little snugger before the nylock opposes torque, same result. I’ve tried breaker bar levering the ball pin assembly downwards while tightening the nut, same result.

The ball pin I pulled off shows evidence of rotation also, it is smooth in the taper and is 0.002" smaller diameter through its taper than the LH old unit. The taper angle (half cone angle) on the old RH unit is 2.74 degrees, the taper angle of the new ball pin is 2.83 degrees, the taper angle inside the carrier is 3.23 degrees.

What to do here? I drive the car about 1,000 miles per year these days. Is there a way to snug that ball pin fully (like the other side did with similar replacement ball pin), should I buy another pair of pins from a different vendor, should I just install and live with small rotation?

And while solving, Rob would you like any photos of the RH brake assembly when I have to pull the drum again to tighten down the wishbone lever after solving this issue?

2

Hi Roger,
It sounds like someone failed to tighten the old nut or failed to put in the split pin (US = cotter pin) or both, and so the hardened pin was turning in there and wore out the tapered hole in the stub axle carrier.
I would look for a replacement stub axle carrier. You can get one from another Mark V or an XK120/140/150, but do not get one from a Mark VII, as the steering angle is different, i.e. the angle that the stub axle makes with a line drawn through the ball pin holes in the carrier.
Be sure to get one from the right side, so you have the two flats on the rear which are used for caster alignment.
It is surprising that they didn’t put the flats on both sides, would have made for one less part number to stock, but I suppose it was Lyons penny pinching.
Jaguar Heaven in Stockton CA had a Mark V when I was there about 20 years ago.
Someone in Australia found a cache of Mark V parts a few years ago.

My brakes are all together, but I would still like to see yours as long as you have it open.