XK 120 front suspension question

Starting the process of assembling the front suspension on my XK120 and noticed the lower a-arm attachment studs are not parallel to the mounting surfaces. I never noticed this before. Can someone clue me into which way the mount should be attached, and is this feature meant to affect the caster of the front suspension, or does the frame shape have something to do with it?
Thanks for your help
Jim

They are made so that they are in a straight line, concentric, with the torsion bars.

Yes, good thing you noticed that before getting it all back together.
The lower wishbone shafts have a taper front and rear.
When installed correctly, it should line up more or less with the line of the torsion bar. Co-linear.

Also note that half the bolts are of a special close tolerance shouldered type.

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And they fit into certain close tolerance holes in the chassis.

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You should consider getting the book Jaguar XK120 explored. It gives very detailed drawings on most of the important assembly parts.

There are four holes on each side, total 8.
On each set of 4, the front inboard and rear outboard are the holes that are specially reamed 13/32" +/- .0005" for fitting the C.3653 special shoulder bolt.
These ensure that the lower shafts are perfectly aligned with respect to the chassis centerline.
The two lower shafts are the same, not left and right, but there is a correct front and rear as we said.

The factory WSM gives you all this, worth having.

Thanks for the info. I’m just happy that I was able to identify the special bolts and find the proper holes for them. I’ve now got it attached. While I have all the experts available I do have another front suspension question. I have the Autobook owners workshop manual, and it mentions that there should be no grease put on the rubber a-arm bushings. That makes sense as I’ve always assumed the bushings torque but not slip in the suspension. The question I have is that I purchased these bushings from Moss and they had a tube of grease included. Just wondering if there is something different with current bushings as compared to the original, or do I need to keep the bushings clean?
Jim

The bushings you purchased are likely urethane plastic. Those require lubrication, or they squeak. They also slightly soften the spring rate. The original Metalastic bushings contained the rubber between two steel sleeves. The shear stiffness of the rubber contributed to the spring stiffness provided by the torsion bars.

Tall end of the shaft goes towards the front.

On the other hand, if they are not urethane, but as original rubber molded over a metal sleeve, there are two other possibilities.

  1. Moss wants you to put some grease on the steel shaft before sliding the Metalistik bushing onto them. That would be good, otherwise in 30 years somebody will be chipping them off with a hammer and chisel like I had to.
  2. The Moss employee doesn’t know that you don’t use grease on rubber bushings.

I used dish soap on mine, which disappeared soon afterwards.

Thanks again for the help. I looked at the bushings and I think they are the urethane as they only have a slip in steel bushing, nothing on the outside. I’ll go ahead and add the grease when I install them.
Jim

In this context we should have also mentioned that the torsion bars are specifically made for left and right, pre-stressed to twist in one direction only, so be sure to get them on the correct sides. They are stamped on the end with the part number and NS for nearside (left) or OS for offside (right).

Hi Rob,
Ref your comment above.
When I was trying to adjust my front ride height which seemed to be way out, I searched for your previously mentioned NS / OS stamping and could find none.
However what I did find was that the torsion bar ends had been painted red / green - maybe by someone with more nautical interests?? The colours do fit with nautical norms ie port / starboard.
Presumably these must be replacement torsion bars. Anyone observed such markings before?
Pics below.


NS/OS and Jaguar C for chassis part numbers on the rear ends.
I don’t know the meaning of ESC.

Rob,

ESC stands for English Steel Corporation Ltd. of Sheffield.

Bob K.

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Great ads; thank you for posting therm!

Eric

As usual, thanks to Graces Guide: a wonderful source of information on British Industry of the past.

Bob K