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Hi fellow Model T'ers!
Let's spend a little time talking about one of the most neglected areas of
our Model T.
The front axle and wheel bearings... As long as the front wheels turn and
the steering
isn't too bad, many of us tend to just assume all is well up front. Maybe
so, but do you
realize that you expend more energy steering your T than in doing anything
else while
driving? Murray Fahnestock used to say that you might as well run your tires
flat if you
didn't have the front end in alignment because you'd certainly grind off
more rubber
with incorrect toe-in!
The three settings we want set correctly are Toe-in (called
"gather" in the Model T
days), Caster (called rake) and Camber. Ford recommended 3/16 inch toe-in.
As
mentioned above, incorrect toe-in can wear out a brand new tire in a couple
of hundred
miles!
Caster is the backward slant (bottom being further forward than top) of the
axle and, in
the T, was controlled by a built-in slant in the spring perches. This brings
up an
important point… It's not uncommon for spring perches to be installed on
the wrong
ends of the axle thus giving a negative caster! Early spring perches (with
the radius rod
ABOVE the axle had the rear of the perch rounded facing the rear. This was
to give
clearance and eliminate the need for a sharp angle on the radius rod that
could
fracture. The later spring perches (radius rod below the axle) had the boss
or lathe
center facing the rear. The correct caster is 5 1/2 degrees. Reversing the
perches will
cause a negative caster and make the car very unpredictable. Remember how a
bicycle
acts when you try to back up?
Camber is what gives our T's the "bow-legged" look. It is designed
to get the contact
point, where the tire touches the road, as close as possible to directly
under the pivot
point of the axle and spindle. This makes turning much easier. The correct
camber is 3
degrees. Measure between the two front wheels at the top of the wheel and
again at
the bottom and there should be a difference of about 3 inches. Camber is
controlled by
the angle of the front wheel spindles.
One quick note… a loose front radius rod ball joint can cause front wheel
shimmy! Front
radius rod joints should always be safety wired and the ball should be a
good fit with
very little play in the socket.
Front wheel bearings should be inspected and greased at regular intervals.
Ford
suggested every 500 miles but once a year should be fine for most of us. If
you're
going to tour the US, you will want to do it more often. When replacing the
outer
bearing, screw it up SNUG and then back off 1/4 to 1/2 turn. A correctly
tightened
bearing will allow the valve stem to turn the wheel to the bottom but there
will be no
play in the bearing when you press in and out on the top of the wheel. Be
careful that
any play you see is actually bearing play and NOT king pin play. You can
eliminate king
pin play by driving a chisel between the axle and spindle to take up any
king pin
movement. Folks with balanced wheels may not see the valve stem move the
wheel but
the bearing should be loose enough to allow that kind of free turning. It's
better to
have a bearing a little too loose than to have it too tight!
Worn out king pins and bushings can also contribute to front wheel shimmy.
To check
for king pin play, jack up a front wheel and then see how much in/out
movement you
have when alternately pressing in and out at the top and bottom of the
wheel. Be
careful that you are not seeing play in the wheel bearings! Frequent oiling
of king pins,
tie rods and drag link balls will help to extend the life of these joints.
Since they are
lubricated with oil, they need to be lubricated much more frequently that
joints which
have grease.
We've covered the high spots of the front-end. Until our next column, I'll
See you down the road....
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