I seem to be getting water leaks from the air inlets in front of the windshield. What should I look for? Is there any way to repair the air boxes or air plenums?
Editor:
The semi-clear air boxes or plenums serve multiple purposes. On planes having multiple air routes, they act as ‘splitters’ for the airflow. They also serve as the water separator. They are very frequently clogged up with years of sediment (sanding dust, paint overspray, windshield sealant debris, airborne dirt, etc.) that has fallen, washed, or blown into the screened air inlets, and the drain outlet nipples are quite small. I have also often found that the plenums have been improperly positioned during other work; and that the water drains are no longer the low point in the box, facing down. That makes matters even worse, for debris accumulation that clogs the outlet.
If you do need to work on them to clear them, be very careful with them, as they will be extremely fragile. Try to position them properly without rough handling; and try to clear them by running heavy wire up from below (through the drain tube). If you do have to remove them, I recommend that you reinforce them all over with extremely thin fiberglass cloth from a hobby shop, and some resin that tests as safe on the plastic (does not dissolve it). White Marine-Tex epoxy has worked well for me, but I have used it primarily to make repairs on them, as opposed to reinforcing unbroken plenums. A thinner mix would be easier to work with, along with the ultra-thin fiberglass cloth. You can paint on a thin coat of the resin, then tap the cloth into it, and wet out the cloth. It will make for a very neat and inconspicuous repair. Replacement plenums are rare, so take good care of what you have.