Video... Front Ball Joint inspection

(Jim XK140 FHC) #1

A bit more taking apart

( #2

To all,
This is great time to ask this question about the top of the lower ball joint contact area, in the stub axle carrier. Without shims, the ball rattles around in its socket with probably 3/32" slop. Some may think this doesn’t matter since the ball is generally sitting in the cup and very infrequently will contact the top of the socket. I think it matters, that’s why the shims are installed. Has anyone made an insert to correct this situation?

Tom Brady
Brockton, MA
52 XK-120 FHC

(Robin O'Connor) #3

To my mind any shims are going to increase the slop, with the older ball joints there is a ring pressed into the upright which is removed when people replace the old style B/j with the newer sealed for life units. Could this be what has happened and you are now going back to the old style?

(Rob Reilly) #4

Tom is correct. Check inside the lower spherical socket of the axle carrier for worn spots. Put a ball in there and feel for lumpiness. Its supposed to be a truncation of a perfect sphere. Normally there is not much load there but rust and road grit can do their mischief.

It looks like you may not have bronze after all, maybe its Ferrobestos or phenolic macarta.
Glad to see you already have the grease fittings.

As I said before, first assemble it without any shims, and it will be (or should be) too tight, and you will see a gap between the carrier and cap. Measure the gap, then you can calculate the approximate amount of shim needed. Trial and error install shims until it is just loose, but not enough to feel rattling. The original spec with bronze insert cups was .010" and there have been subsequent revisions of this spec in various sources, I suppose as the cup material changed. In my XJ manual it is .004 to .006, and they tell you to put in too many, then remove one by one until it is tight, then put 004 to 006 back in.

I’ve seen others mention using sealed XJ ball joints, but the bolt pattern on my 74 XJ is different and it would not fit. I don’t understand, must be missing something here.

(Robin O'Connor) #5

There are instances where the aftermarket B/Js have not been drilled correctly. I have fitted the sealed units to my ‘65’ ‘S’ type.

(wardell) #6

Correct me if I’m wrong, but I think the sealed type can only be fitted to the MK2 range. The XK s and 7, 8 and 9 range is completely different in all respects and uses a smaller ball.

(Roger King) #7

To bring this back to Jim’s video, I would replace those balljoints without even thinking about it, Jim. Any signs of pitting, flats, scoring or wear of any kind indicates that replacement is needed. The damage caused by the removal tool is also good reason.
I would use either a ‘pickle fork’ or a conventional ball joint press as a last resort. Usually hitting the side of the casting containing the taper, with the nut loosened, is enough to shock the taper free and does less damage, although given what you’re coming up against in this car, who knows?
Keep up the good work


(Jim XK140 FHC) #8

So when it comes to reassembly , new bushes , ball joints , what is the starting point for rough camber/ castor shimming ? Do you put it back to how it was or take them all out and start from nothing ?

(Rob Reilly) #9

The bolt pattern on our XK lower caps is a rectangle. The bolt pattern on my XJ is an isosceles trapezoid.
Glad to see you are noting left and right hand parts. It can get confusing when they are all painted and ready to go back on. Especially torsion bars, NEVER put them on the wrong sides. Lower wishbone shafts and stub axle carriers as well.
Presuming you have the manual, it is possible to set up the castor and camber on a bare frame with careful measurement on a flat floor. You have to simulate it into the normal riding height with no tension on the torsion bars. But perhaps easier on the mathematics to wait until it is fully assembled. Putting it back how it was is as good a starting place as any.

(Jim XK140 FHC) #10

Thanks to All for the tips

(Roger King) #11

I would reassemble with any shims as they were when you dismantled it, then check it carefully.
Problems might arise if it had an alignment done after the rot had set in to the chassis. Changes in shape might have affected that - although frankly I very much doubt it has, as a car that’s been allowed to get as rough as that one was is unlikely to have been treated to a full alignment. Most people only bother with toe-in on the steering, and it’s only relatively recently that workshops who can measure castor and camber have become more numerous. Well, here, anyway - don’t know about the US.