MG Car Club of South Australia
TeChnical TopiC
By..Bob Schapel
TC STEERING
TC steering is notorious.
However,
when all components are in good condi-
tion and all adjustments are well set, it
still does the job reasonably well.
The main fault with the standard TC
steering box is that the top plate (with
three bolts, sometimes called Side-plate)
and the rocker shaft (which bears
against it) are both unhardened steel.
As a result, the two metals “pick-up” on
each other, even when properly im-
mersed in oil.
The resultant wear quickly introduces
friction and free-play, which makes the
steering heavy and imprecise. This fault
can easily be rectified by case-
hardening the top plate.
My road TC and race TC have both had
this treatment. Tony Ohlmeyer alerted
me to this solution about 50 years ago.
He told me that such hardening was
standard on pre-war cars. He also sug-
gested having a “flash of hard chrome”
put over the case hardening, because
hard chrome has a lower coefficient of
friction. I really should try that extra
step.
There are other “cures” such as fitting a
Datsun or VW steering box. I have been
told that these two options do make a
TC easier to drive, although they would
not suit a motorkhana situation, where
the extra turns from lock to lock might be
a disadvantage.
I have only ever driven TCs with stan-
dard steering boxes, so I am not quali-
fied to say much about the non-MG op-
tions. Do they make a TC feel unlike a
TC to drive? Is that a good thing or bad
28
thing? We’ll leave that to the philoso-
phers!
Our own Ian Curwen Walker made a
modification to his TC steering box
about 50 years ago. He adapted a roller
taper bearing to the top of the rocker
shaft. This helps centralise the shaft
and removes much of the friction. The
Tomkins kits, work on the same princi-
pal.
I think this style of mod should be ar-
ranged, the same way Curly did his. He
set it up with only a few thou’ clearance
between rocker shaft and plate. This
prevents the rocker shaft from excessive
upward flexing during sudden shock
loads, and should reduce the chances of
it cracking.
Over the years, I have seen several
cracked rocker shafts. Many years ago,
Peter Hage had his break. Fortunately,
he was slowly pulling out of a parking
spot at the time.
It is important to grease TC king-pins
frequently. Steering effort usually feels
noticeably lighter after such greasing.
During the T-Type convoy to the 1972
Melbourne Natmeet, I remember Curly
religiously greasing his king-pins about
half way through the trip.
Driving a TC, with a standard steering
box, involves constant correction. Effort
is applied to the steering wheel until fric-
tion is overcome. When friction is over-
come, the car suddenly responds. How-
ever, once things move, they move too
far …. and the steering wheel has to be
turned back the other way. This results
in the characteristic “see-sawing” motion
of the steering wheel. If there is exces-
sive free-play in the steering, this effect