Being electrical in background, I had to laugh at your solution (enjoyable laugh).Well finally installed a small vent in filler cap. I hope this will work. It is a oil filler from an old electric motor. I drilled through the filler cap and then enlarged the top of hole to accept the shaft and cap that is 1/4” . It is not to high out of the cap but will allow air to escape the front axle. Will see how it works in the summer. Maybe I will be changing it out to some of the other ideas from this forum. Time will tell.
so was able to put the vent I wanted to try into the filler plug on the front axle of my bx1860. It is a oil filler from an old electric motor. I driller completely through the filler cap on an angle to allow an air passage vent then drilled the cap to 1/4” to push the vent into cap. Has a foam inside the tube in case of any dust. Will see this summer how it works. Should allow a free movement of air to keep the pressure down.
Not sure you would even need any foam inside since there is a spring loaded cap on the top (I assume held closed by a spring). Suggest you make sure the foam is open cell and will pass air through it. Closed cell foam would not pass air and act like a plug.