[xk] More questions about center track rods (xk120)

I just read thru a bunch of older posts about the xk120
front suspension (1954 OTS). My steering is seriously loose
and the problem appears to be a wobbly idler arm shaft
(bushing worn out?), a loose pitman arm on the bottom of the
steering box, and a center track rod with stripped out
threads (female ends are stripped out). My car has the fixed
tie rod ends where you adjust toe-in/out by rotating the
center track rod.

Questions:
Is rebuilding the idler assembly a DIY job? Any idea where I
can get an idler arm bushing? Not XK’s and SNG don’t have it

Any idea where to get a new center trackrod (not XK’s or
SNG). Any reason I can’t have a local shop machine one out
of bar stock?

John Feng–
John
MA, United States
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In reply to a message from John7 sent Tue 26 Jul 2011:

John,

Regarding making a replacement part from barstock, my car is not on
premises here to check but I would expect that the original part
was a forging. If that is the case, making one of ‘‘bar stock’’
should be done with great care - if at all - to be sure that
material properties of whatever you use are an appropriate
replacement for the service.

Karl–
The original message included these comments:

SNG). Any reason I can’t have a local shop machine one out
of bar stock?


karl
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John F;
On rebuilding an Idler Assembly, you ask if it is a DIY Job… It is for
me…
Go to a “local” (Boston) Bearing Supply house, give them the dimentions of
the bushing (ID, OD & Length)… A little long is okay, you can make then
shorter, you just can’t make them longer… Same with the ID… A bit small
is okay as it would need to be reamed to fit the Idler Shaft anyway…
The problem would be if your Idler Shaft is chewed-up… That piece is
hardened steel… You aren’t going to turn one of those on an R&D Lathe.
I bought a pair of Track Rod Ends from Larry Springer (down in Virginia)
several years ago, he might have a good used Track Rod…
This all assumes you’ve tried Bill Bassett… He’s right in your back
yard, has reasonable prices and is a helluva lot more pleasant to deal with
than the left coast outfit.
What about John & Tom Brady… they are just around the corner from
you…
Machining a Track Rod isn’t as easy as it sounds… It’s a “tube”, not a
“rod”… One end has Left-Hand Threads, the other has Right-Hand Threads…
Niney-nine to one says they are a British Thread…
Lastly, unless you like the “one piece” Tie-Rod sections, the MK VII
uses the same set-up except with replaceable Tie-Rod Ends… High initial
cost but a helluva lot cheaper when one Tie-Rod goes bad!
Charles #677556.----- Original Message -----
From: “John7”

I just read thru a bunch of older posts about the xk120
front suspension (1954 OTS). My steering is seriously loose
and the problem appears to be a wobbly idler arm shaft
(bushing worn out?), a loose pitman arm on the bottom of the
steering box, and a center track rod with stripped out
threads (female ends are stripped out). My car has the fixed
tie rod ends where you adjust toe-in/out by rotating the
center track rod.

Questions:
Is rebuilding the idler assembly a DIY job? Any idea where I
can get an idler arm bushing? Not XK’s and SNG don’t have it

Any idea where to get a new center trackrod (not XK’s or
SNG). Any reason I can’t have a local shop machine one out
of bar stock?

John Feng

In reply to a message from John7 sent Tue 26 Jul 2011:

there is one other thing here guys…there IS a problem often hard
to find being the nut which surrounds the steering worm. This gets
stripped on the inside race and wears very badly. One has to
completely dissassemble the steering box to discover this . It is
caused be allowing the steering box to run out of oil and then
repeatedly reefing on the steering wheel without allowing the car
to move forward at the same time.What happens is that ALL the
pressure is on the point of one tiny hardened ball bearing. It
just strips facing right off the nut. My steering was soo bad that
it used to shimmy all over the road when this happened. NO
longer… but I found it very hard to find the nut.–
godfrey
pender island bc, Canada
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Wobbly idler arm shaft is most likely the idler arm itself is moving on the
shaft and wearing out the hole, because the shaft is rusted into the housing
and not turning as it should. The shaft does not just come out with a push
in a hydraulic press. It is threaded at the top end 11/16-11BSW, threaded
into the housing, so you have to unscrew it. The bottom half of the shaft is
straight inside the housing, and the lower end is tapered to fit the idler
arm. Get it off and in a bench vise, put the arm on tight, remove the top
cap, then many cycles of heat and penetrating oil will get it loose.
The track rod is made of ordinary steel tube, and it measures 21/32-16 tpi
on the thread, not sure what that is, but left hand at one end.
Most parts from a Mark V are the same, except the idler housing is at a
different angle and the track rod might be longer.
Rob Reilly - 679187

In reply to a message from R_and_J_Reilly sent Wed 27 Jul 2011:

Ok, my machinist tells me the track rod end thread is
11/16-16 UN, a non-preferred size, but nevertheless listed
in Machinery’s Handbook.–
XK120 FHC, Mark V saloon, XJ12L Series II, S-Type 3.0
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In reply to a message from Bishop13 sent Tue 26 Jul 2011:

Charles,
Thank you.
One thing that puzzles me is why a '54 would have the fixed tie rods+adjective center rod. I thought Jaguar went to the newer style (adjustable tie rod ends) well before 1954. Perhaps this Car was converted backward to yhe older stylewhen it was restored decades ago?..

Doesn’t matter though. If the restoration shop put in a track rod with stripped out ends, there may be more skeletons to be uncovered. I might be better off just putting in a complete, new steering link assembly.–
John
MA, United States
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In reply to a message from John7 sent Wed 27 Jul 2011:

Adjustable center track rod with adjustable tie rod ends (3
adjustments in total) was the initial design created for the
Mark V saloon and also used on the XK120.
The Mark V needed all 3 because the track rod was bent to
clear the starting crank handle and would not normally be
rotated for adjustments.
Deleting the adjustable tie rod ends and just keeping the
adjustable center rod on XK120 was a cost savings since only
one was really needed.
The adjustable tie rod ends would come back with the rack
and pinion steering on XK140, since the center rod was
eliminated, i.e. replaced by the rack.–
XK120 FHC, Mark V saloon, XJ12L Series II, S-Type 3.0
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