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Tom Sotomayor
Why does my MGB lean to
one side? This is a question that many people have brought up. Using
these methods you can figure out exactly where the problem is. Lean can
be caused by any of the following:
1. The springs are
worn/worn out. Worn out shocks will lead to worn out springs.
2. Poor quality replacement springs.
3. Mismatched tires or tire pressure.
4. The mounting points on the body are not correct.
- The factory put them in the wrong spot.
- An accident upset the frame geometry.
- Corrosion upset the frame geometry.
- The rubber bushes and/or mounting pads are worn, missing or
distorted.
- The suspension has been rebuilt and the nuts/bolts were tightened
with the suspension at “full droop” or before it was “bounced” and
any “set” has been removed.
Before doing any serious
measuring of the lean, you should make sure that your tires all match
and they have the same air pressure! Also bounce the car to remove any
suspension "set". It is very important to find out if the garage floor
is in fact level. This may at first sound like we’re doing it backward,
but bare with me. Measure from the same relative points on the car –
most people do it from the floor to the stainless belt line directly
above the wheel centers. Do this for all 4 wheels. Mark on the concrete
(with chalk) the contact patches for all 4 tires, plus the exact points
you measured from the floor to the belt line. Move the car. Use a
carpentry level to see how much height difference there is between the
contact patch and the measurement point (typically over a few inches it
should be within 1/8 of an inch or so). Now you’ll need to use a "water
level". A water level can be easily made from a long piece of clear
tubing filled with water. Over any reasonable distance the water will
find the same level at each end. Of course the ends of the tube must be
above the level of the water! For this task a piece of ½ inch ID (inside
diameter) flexible clear tubing about 20 feet long will work well.
You'll need two (or four) markers that are exactly the same height,
about 4-12" high works well. They can be anything - blocks of wood, jack
stands, bricks, etc. Place your markers on the contact patches and using
the water level, see how far each one is off from the others. Adjust
your previous measurements accordingly.
To be more accurate, you
could "shim" the floor to bring the contact patches back into level,
move the car back into position and then re-measure. This is about as
close as you can get without having VERY expensive equipment.
You should also measure
the length of each coil spring and the arch height of each leaf spring
under static load. If you measure a front spring from the inside top of
the cross member (just under the shock) to the bottom of the spring pan,
it will give you a comparative length of the coil springs. Do the same
for the leaf springs - measure from the top of the axle to the rear
frame arch. This leaf spring test WON'T tell you if any differences from
side to side are a bad spring or a "bent" frame. You will be able to
tell which if you stretch a string from the front leaf spring eye to the
lower rear shackle pivot and get a measurement from the axle/spring to
the string. Or you can measure from the front and rear spring eyes to
the floor, as well as from the axle tube to the floor. You'll need to
find the level of the floor in those three spots as outlined above. This
will give you the comparative arch of each spring.
With this information in
hand, it will be easy to determine where the problem(s) are located.
From there you can affect repairs. |