Re: TC King Pins

[Mark Jablonski]

Dear Listers

The axle eyes on my TC are worn to about 0.755" in the middle and about
0.765" at the bottom ends. It seems to me that whilst I am overhauling
the front end I should do something about this. I intend reaming out
the eyes to 0.015" oversize and fitting oversize pins. Does anyone
know of a supplier of oversize kingpins? Alternatively, does anyone
have a recommendation for the steel to use for making new pins? The
only reference I have been able to find is in Wheatly & Morgan (a
restorer's "bible" of many years ago) where it recommends a 3% nickel
case hardening steel. They suggest KE169 a Kaiser & Ellison steel (for
which I don't have the composition). A data sheet for BS970 EN33,
which is a 3% Ni case hardening steel, states this steel to be suitable
for kingpins. Does anyone have any other suggestions for the repair or
should I not worry about the amount of play? (The car will not be used
in competition.) With the cotter pins in there was no detectable play
with the car jacked up but I suspect that cornering forces will cause
the pins to pivot around the cotters and further wear the eyes.

Mark Jablonski
TC6022

[CFritz7001@aol.com]

For what it's worth, I think I'd be inclined to stay with standard pins, and
leave the axle eyes as they are. Reaming them out is going to make them
weaker than they are right now. If there is no perceptible with the cotters
installed, there's probably (IMHO) nothing to be concerned about. They
weren't a snug fit when I replaced Betsy's for the first time back in 1955,
when she was only 7 years old! What you're considering to be wear may well
be mostly designed-in clearance.
However, if the wear REALLY bothers you, POSSIBLY the axle eyes could be
built up by welding, then reamed out to fit standard size kingpins, but I
don't know what the heat will do to the Axle.
Regards,
Carl Fritz
TC #6756

[Frank O_ The Mountain]

In a message dated 12/8/99 7:15:25 PM Pacific Standard Time,
m.jablonski@mei.unimelb.edu.au writes:

>

I have this same problem with my TA. I can bang the cotters in and tighten
up the pins but eventually they get loose again. I have been advised to have
the axle "smithed" back to its former glory by a blacksmith. Not an easy
thing to do here in San Francisco these days. A fellow TA owner reamed his
and put in a sleeve, staying with standard pins, I am lothe to do this given
the small amount of meat in the axle eyes.....so I'll be interested in the
list advise on this problem. It must affect a lot of our cars now after 60
years of service!

It is however somewhat dangerous to allow this condition to persist as I have
seen pictures in MMM publications where the king pin had about cracked in two
by the forces involved.

Terry

[Michael Card]

Mark, Terry TC9477 [under rebuild] has the same beam axle worn-eye problem. I prefer to stick with the standard size king pins, and to seek a solution with the axle. I am told that some axles here have been sleeved, without problems or failures. Have just about tracked down the machinist who did the work, and I am leaning towards this solution rather than reworking the eyes. However like you both, I would like to hear of opinions of other listers on this matter, before I go ahead. Mike Card UK TC8233

----- Original Message ----- From: TATERRY@aol.com To: m.jablonski@mei.unimelb.edu.au ; mg-tabc@egroups.com Sent: Thursday, December 09, 1999 3:26 PM Subject: [mg-tabc] Re: TC King Pins
In a message dated 12/8/99 7:15:25 PM Pacific Standard Time,
m.jablonski@mei.unimelb.edu.au writes:

>

I have this same problem with my TA .... A fellow TA owner reamed his
and put in a sleeve, staying with standard pins, I am lothe to do this given
the small amount of meat in the axle eyes..... Terry

[Peter Pleitner]

Hi Michael and Terry and Mark, I'm very interested in going the O/S king pin route for the following reasons: 1. If the wear factor is on the order of ten to twenty thousand the reduction in strength at the eye of the beam I believe is well within the design limit and surely the metallurgical variability of the axle. 2. Sleeving would require even more removal of metal. The sleeve does not contribute to strength, rather it could only add to the stress if pressed in. 3. A slightly O/S kin pin would be handy for some because they could simultaneously obtain some more life from slightly worn bushings. So those are my three cents worth of opinions, which of course are subject to change when someone offers more coinage for thought. Cheers, Peter

-----Original Message-----
From: Michael Card [mailto:mike.card@mcmg.freeserve.co.uk]
Sent: Thursday, December 09, 1999 11:25 AM
To: TATERRY@aol.com; m.jablonski@mei.unimelb.edu.au; mg-tabc@egroups.com
Subject: [mg-tabc] Re: TC King Pins

Mark, Terry TC9477 [under rebuild] has the same beam axle worn-eye problem. I prefer to stick with the standard size king pins, and to seek a solution with the axle. I am told that some axles here have been sleeved, without problems or failures. Have just about tracked down the machinist who did the work, and I am leaning towards this solution rather than reworking the eyes. However like you both, I would like to hear of opinions of other listers on this matter, before I go ahead. Mike Card UK TC8233 ----- Original Message ----- From: TATERRY@aol.com To: m.jablonski@mei.unimelb.edu.au ; mg-tabc@egroups.com Sent: Thursday, December 09, 1999 3:26 PM Subject: [mg-tabc] Re: TC King Pins
In a message dated 12/8/99 7:15:25 PM Pacific Standard Time,
m.jablonski@mei.unimelb.edu.au writes:

>

I have this same problem with my TA .... A fellow TA owner reamed his
and put in a sleeve, staying with standard pins, I am lothe to do this given
the small amount of meat in the axle eyes..... Terry

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[PMS GB Ltd]

Message text written by "Michael Card"

>TC9477 [under rebuild] has the same beam axle worn-eye problem. I prefer

to stick with the standard size king pins, and to seek a solution with the
axle. I am told that some axles here have been sleeved, without problems
or failures. Have just about tracked down the machinist who did the work,
and I am leaning towards this solution rather than reworking the eyes.
However like you both, I would like to hear of opinions of other listers on
this matter, before I go ahead.<

I once (many years ago now) did the king pins on a TC which had axle eyes
which were fitted with pressed in, thin ( about 0.020 inch thick) stainless
steel sleeves. The king pins were well worn on the steering stub axle
bearing surfaces, but the axle pin area was perfect and showed no sign of
movement. New standard pins were fitted and the pin was a good sliding push
fit before tightening up with the cotter.

This might be an option.

Clive Sherriff

[Michael Card]

Peter, Clive, and all Peter, I agree with your logic at points [1] and [2], but you might accept that minimum metal removal is likely to be more important than the additional hoop stresses in the axle eye resulting from a shrunk-in or pressed-in sleeve. I understand your point [3, oversize pins], but keeping with standard pins makes life easier for those like me who do not have a lathe or milling machine to make up special items and have to pay for all machining. Clive's story of what he did some time ago with the stainless steel sleeves sounds similar to the solution I have heard elsewhere. Clive, did you [a] cool the sleeve / heat the eye, or was it a slight interference pressed fit, or [c] just a firm sliding fit? I assume that you reamed the sleeve to size afterwards if it were {a] or ? If I could make a similar repair as Clive has described, with a 0.020" thickness [on radius] sleeve, I think that I would be happy .... .... but I'm still waiting to hear Peter's and Clive's further thoughts and the ideas of others. Mike Card PS Some months ago, while thinking about this problem, I made a rough check on the stress levels in the axle at the king pin hole, making some assumptions about shock loading etc. I only checked for bending moment and resultant stresses under heavy braking and assuming that a wheel hits a pot-hole at the same time. I think that this might be close to maximum load conditions, except for abnormal events like say hitting a kerb sideways etc. Rather rough calcs, but they led me to conclude that the loads and stresses at the axle eye are HIGH. The culprit is of course the short [vertical] length of the eye in the axle. Hence the concern that Peter has about removing as little metal as possible.

----- Original Message ----- From: pleitner@dundee.net To: mike.card@mcmg.freeserve.co.uk ; TATERRY@aol.com ; m.jablonski@mei.unimelb.edu.au ; mg-tabc@egroups.com Sent: Thursday, December 09, 1999 6:07 PM Subject: RE: [mg-tabc] Re: TC King Pins
Hi Michael and Terry and Mark, I'm very interested in going the O/S king pin route for the following reasons: 1. If the wear factor is on the order of ten to twenty thousand the reduction in strength at the eye of the beam I believe is well within the design limit and surely the metallurgical variability of the axle. 2. Sleeving would require even more removal of metal. The sleeve does not contribute to strength, rather it could only add to the stress if pressed in. 3. A slightly O/S kin pin would be handy for some because they could simultaneously obtain some more life from slightly worn bushings. So those are my three cents worth of opinions, which of course are subject to change when someone offers more coinage for thought. Cheers,

[Mark Jablonski]

Dear Mike Card and others

I would be concerned about removing .040" (on diameter) from the axle
eyes.

Someone was concerned about oversize pins requiring material removal
from the knuckles. I don't think this would be necessary - I think the
standard bushes should suffice and even the oil grooves would still
remain. At 0.015" oversize there would only be 0.0075" removed from
the wall of the bush and hence from the depth of the oil grooves. They
are a lot deeper than this.

Mike in answer to your questions re the fitting of a sleeve to the axle
eye, (should it be possible) I think that it would only need to be a
light interference fit, something you could easily drive in with a "G"
clamp. the pin is stationary and is held there by the cotter pin, once
installed nothing should move. It would only need enough to hold it in
place as you drilled and reamed it after pressing in. As I said above
though, I'm not convinced that it would be safe to remove enough
material to make room for a bush.

I take your point about making it easier to maintain with standard
pins. In the case of king pins I think that they would have to be
centreless ground as they would be case hardened so they would be
beyond the workshops of all but the most well-healed.

Bob Grunau has suggested hard chrome plating the pins. This would make
replacing the pins a little easier than making them from scratch but
would still necessitate grinding after plating. I still have to
investigate the relative costs and difficulties. I will let the list
know what I find out and which way I decide to jump.

Mark Jablonski

[john.lynch62]

Hi Fellow Listers

We have had the custody of TC0532 for two years.
There is no apparent wear in the king pins and they move freely but I
have simply been unable to get any grease in them.
I have a new set of John James' king pins but do not really want to
fit them until next winter, particularly as those fitted show no sign
of excessive wear.
On inspection, the top bushes of those fitted are different form the
new set. Approximately 1/4 inch of bush protrudes above the stub
axle and the outside diameter of this protruding part appears to be
significantly greater than the replacement bushes. Has a set of
early TA bushes been fitted and does this explain anything?
The nipples are not blocked and curiously, when the king pin caps and
bolts are removed, grease is easily pumped into the top nipples but
comes out of the threaded hole. When the caps and bolts are in place
it is impossible to get any grease in them.
Can anyone explain the existing king pin set up and advise on how I
can grease them? I am concerned about not being able properly
maintain part of the steering system.
Also, the bolt heads on the back of the stub axles forming part of
the steering stops are not tightened right in. Why is this, is it
part of the steering adjustment and, if so, what is the criteria on
where they should be positioned?

Thanks in anticipation.

John Lynch
Amersham, England

[E.Worpe@surrey.ac.uk]

Hi John,
Some king pin sets were intended to be greased through a nipple
screwed into the top of the king pin. A blind hole drilled along the
axis of the king pin then acted as a manifold to two radial drilled
holes feeding the bushes. It would seem that you have just such a
king pin allowing grease pumped through the stub axle nipple to
exude through the blind hole.
If early TA type bushes have been fitted they would have to be
fitted with their flanges on the outside, fitting them with the flanges
on the inside would block the beam axle eye as TB/TC stub axles had
thicker sections supporting the bushes.
I wonder if your grease gun is powerful enough to pump grease
along the groove machined in the bushes. The groove is open at one
end of the bush to allow grease to reach the thrust washers adjacent
to the beam axle eye. With TA bushes inserted the wrong way, grease
would exude uselessly from either end of the king pin. It would be
worth fitting John James bushes as these have been specially made
to the original specification and allow grease to lubricate the thrust
washers ( if they are fitted the correct way ).
As TA type bushes seem to have been used, a further problem may
occur in that the grease holes in the bushes may not line up with
the nipples screwed into the stub axle. You may be able to extend
the life of the bushes by greasing them through a nipple screwed in
to the top of the king pin, but in any case a more powerful pump
action grease gun may be needed such as a Wanner. The holes in the
king pins are usually tapped 1/4 BSF. Do phone if you need any further
help.
Hope this helps in the meantime, Eric.


-----Original Message-----
From: mg-tabc@yahoogroups.com on behalf of john.lynch62


We have had the custody of TC0532 for two years.
There is no apparent wear in the king pins and they move freely but I
have simply been unable to get any grease in them.
I have a new set of John James' king pins but do not really want to
fit them until next winter, particularly as those fitted show no sign
of excessive wear.
On inspection, the top bushes of those fitted are different form the
new set. Approximately 1/4 inch of bush protrudes above the stub
axle and the outside diameter of this protruding part appears to be
significantly greater than the replacement bushes. Has a set of
early TA bushes been fitted and does this explain anything?
The nipples are not blocked and curiously, when the king pin caps and
bolts are removed, grease is easily pumped into the top nipples but
comes out of the threaded hole. When the caps and bolts are in place
it is impossible to get any grease in them.
Can anyone explain the existing king pin set up and advise on how I
can grease them? I am concerned about not being able properly
maintain part of the steering system.

John Lynch










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