A trick to find a windshield leak

My father's business was making operator's cabs for the construction industry and this obviously involved fitting glass. This is how he tested for leaks.

He designed the system in the 1950's of using locking strip in a rubber section to hold the glass, the system used by Honda on our cars. One of his points of design was that the glass could not be pushed in easily, but could be pushed out easily to escape in the event of doors being jammed, (been there in a rally car, it works, put your foot in a corner and push).

ANYWAY, to the leak....

Take a bottle of water and start at a lower corner of the rubber to body join and work upwards to the top corner, then to the centre of the screen. If this does not show the leak, then repeat on the other side. The lower edge rarely leaks. 

Also, look for staining on the rubber inside the car, as it can occasionally enter between the glass and the rubber.

The outside leak point and the inside drip point are rarely opposite each other, there is a gap between the glass and rubber and another between rubber and body that allows water to lead us a merry dance as these gaps act like a tube. The usual outer leak point is the top corner of a screen and this will show inside by running out of the rubber where two panels are joined, usually at the bottom of the screen. Rubbers can shrink with age and this will reveal the recess into which the seals sit, always at the top as the glass will always settle downwards with the expansion and contraction of the shell over the years.

Once you have found the leak, it can very often be cured by pushing the rubber up at the top corners by using wood on the glass to avoid scratches.

I have had leaks on 6 of my firstgens. and have cured all of them without resorting to glues or fillers, however I am aware that some of you may suffer seal degradation due to sunlight and other climatic conditions. One car dripped water on my foot when driving, its entry point was found to be at the top on the passenger's side, so it traveled halfway around my windshield.

Always have a look and see if your rubbers have moved, you will usually see a change in color or a line left by the rubber before it moved.

A long missive, but it is cheaper to check first than having some "expert" tell you that the screen has to come out and a new seal and glass is required (especially if it is a laminated windshield).

Thor