J
jfriese
Guest
The Problem: Damage to cowl area around windshield wiper pivot.
We had a lot of fun at the meet last weekend and many rides were
given.
The car did suffer a bit of nasty collateral damage though. When I
bought
this Amphicar, the paint around the right windshield wiper pivot was
damaged and
some bending of the metal around there was evident. It appeared that
it had been repainted before
and showed signs of repeated stress. I didn't know what
caused it, especially since the wipers seemed to work normally. Hugh
thought it
might be that the pivot had seized at some time and had been replaced.
I replaced both pivots, just to be safe, and snapped the linkages back
where they were. It turns out that those linkages were not adjusted
to the correct length and I put them back just the same way. When a
wave hit the wipers, the right
hand wiper over rotated, past the pivot line, and jammed
against the underside of the cowl. This stalled the wiper motor, but
not
before the motor put enough force against the pivot to bend the sheet
metal again and re-crack the paint and a marginal patch that had been
done to the metal.
Bummer. Another patch job for the body shop and I don't know how much
it will entail to make
the blemish go away. I already re-aligned the
linkages and I doubt it will happen again but I wish I had figured
this
out before now. It may be a freaky problem but the consequences are
rather grim. I would check whatever Amphi's you work on for this
weakness. The body shop owner said that modern cars have reinforced
metal
around these areas to prevent such problems. Amphi's don't.
Question, if wipers are working properly. How do you know they are not
adjusted properly?
What you have to do is stop the wipers at the furthest point in their
sweep, by
simply turning off the ignition, and checking the position of the
right hand
"underside" arm. You want to be sure that a little bit of additional
force
(representing a wave or wiper inertia), pushing the right hand wiper
to the
outside, is not able to over rotate that lower arm past the line of
the pivot.
The fix is to simply lengthen the linkage from the arm to the motor.
Remove the
wiper arms, before you restart the system, since fooling with these
linkages
changes the positions of the arms on the pivots. While you're working
under there, you want to
check to see that the two lower arms are coordinated. This is simply
making sure that the
connecting link between the pivots is adjusted to the same distance as
the distance that separates
the pivots. Sounds complicated, but it's simple. With the motor
linkage disconnected adjust the
position of one of those lower arms to be perpendicular to the edge of
the trunk compartment. I
simply held a popsicle stick along the side of the lower arm, with the
end sticking out so that I
could see it's position. Then check the angle of the other lower arm.
If it's not also perpendicular
to the edge of the trunk, adjust the length of the connecting link to
make it so.
I believe that the motor drive rod length to the right hand pivot is
the most
critical adjustment. It's the right pivot that's most likely to over
rotate, though the left arm could do
it too. You simply have to be sure that the motor drive arm length is
long enough that any
reasonable amount of additional rotating force is not able to force
the pivot arm to over rotate and
jam and, if you've done that "perpendicular" adjustment, the left
lower arm should also be in the
correct position. Once those lower arms and linkages are correct,
then reinstall the wiper arms.
John Friese
67 White
67 Red
We had a lot of fun at the meet last weekend and many rides were
given.
The car did suffer a bit of nasty collateral damage though. When I
bought
this Amphicar, the paint around the right windshield wiper pivot was
damaged and
some bending of the metal around there was evident. It appeared that
it had been repainted before
and showed signs of repeated stress. I didn't know what
caused it, especially since the wipers seemed to work normally. Hugh
thought it
might be that the pivot had seized at some time and had been replaced.
I replaced both pivots, just to be safe, and snapped the linkages back
where they were. It turns out that those linkages were not adjusted
to the correct length and I put them back just the same way. When a
wave hit the wipers, the right
hand wiper over rotated, past the pivot line, and jammed
against the underside of the cowl. This stalled the wiper motor, but
not
before the motor put enough force against the pivot to bend the sheet
metal again and re-crack the paint and a marginal patch that had been
done to the metal.
Bummer. Another patch job for the body shop and I don't know how much
it will entail to make
the blemish go away. I already re-aligned the
linkages and I doubt it will happen again but I wish I had figured
this
out before now. It may be a freaky problem but the consequences are
rather grim. I would check whatever Amphi's you work on for this
weakness. The body shop owner said that modern cars have reinforced
metal
around these areas to prevent such problems. Amphi's don't.
Question, if wipers are working properly. How do you know they are not
adjusted properly?
What you have to do is stop the wipers at the furthest point in their
sweep, by
simply turning off the ignition, and checking the position of the
right hand
"underside" arm. You want to be sure that a little bit of additional
force
(representing a wave or wiper inertia), pushing the right hand wiper
to the
outside, is not able to over rotate that lower arm past the line of
the pivot.
The fix is to simply lengthen the linkage from the arm to the motor.
Remove the
wiper arms, before you restart the system, since fooling with these
linkages
changes the positions of the arms on the pivots. While you're working
under there, you want to
check to see that the two lower arms are coordinated. This is simply
making sure that the
connecting link between the pivots is adjusted to the same distance as
the distance that separates
the pivots. Sounds complicated, but it's simple. With the motor
linkage disconnected adjust the
position of one of those lower arms to be perpendicular to the edge of
the trunk compartment. I
simply held a popsicle stick along the side of the lower arm, with the
end sticking out so that I
could see it's position. Then check the angle of the other lower arm.
If it's not also perpendicular
to the edge of the trunk, adjust the length of the connecting link to
make it so.
I believe that the motor drive rod length to the right hand pivot is
the most
critical adjustment. It's the right pivot that's most likely to over
rotate, though the left arm could do
it too. You simply have to be sure that the motor drive arm length is
long enough that any
reasonable amount of additional rotating force is not able to force
the pivot arm to over rotate and
jam and, if you've done that "perpendicular" adjustment, the left
lower arm should also be in the
correct position. Once those lower arms and linkages are correct,
then reinstall the wiper arms.
John Friese
67 White
67 Red
