There is a corollary to Murphy’s Law that goes: ‘If everything is going well you have obviously overlooked something”.  Well, just when I thought I was doing really great and my hubris was at an all-time high, the corollary kicked in and brought me back to earth with a thud.

I was just starting to build a template for the upper firewall, so I temporarily clamped the defroster vent, the master cylinder, and the wiper mechanism into place, when I noticed something odd.  The wiper motor assembly wouldn’t fit below the windshield without fouling the cross-beam that I had so carefully welded beneath the windshield. But it had fit on previous mock-up attempts.  After staring at the wiper mechanism in disbelief for the best part of an hour, it finally dawned on me that the motor crank was interfering with the cross-beam by an astonishing 5/8 “.  How could this be when it had fit perfectly so many times before?   Then it occurred to me that in all previous fittings that the wiper motor arm was pointing upwards. It was now pointing downwards.  I had forgotten to take into account that the wiper motor arm did not oscillate back and forth like the wiper arms, but instead the motor arm rotated a full 360 degrees,. I had forgotten to allow clearance for this. Doh!

Here is the clearance for the wiper mechanism before modification.

beamdistance

Here is what happened to the clearance when the wiper arm is rotated downward.

WiperInterference

After looking at unworkable solutions like extending the wiper spindles and modifying the wiper linkage, I realized that there was only one practical solution and that was to notch the cross-beam to clear the wiper linkage and sister up a piece of cross-beam below the notch to restore the integrity of the cross-beam.

Here is the new beam sistered in:

sistered beam

 

 

 

 

 

 

 

 

 

 

 

 

There was a snag (isn’t there always?),  the pedal mount was welded to the cross beam right where the notch had  to be cut.  That meant that the pedal mount had to come out.   This was my second attempt at a pedal mount so this consequence really hurt my ego.

But there is often a bright side to having to do something so dire.  Removing the old pedal mount gave me an opportunity redesign the pedal mount so it does not protrude into the footwell and to simplify the sheet metal of the firewall and make it easier to build.

For reference, here is the original (second version) of the pedal mount:

assembly1a
Now here are front and rear views of the new pedal mount with the modified cross-beam.

pedal mount frotn view 3:4

pedal mount rear view

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