Every time it rains the back hatch of my 95 Honda Odyssey fills with water. I can drain most of it through the key latch, but there are several gallons of water in there. What do I need to do? Please don’t tell me that the entire back hatch has to be replaced.
The first thing you need to do is figure out how it’s getting in. Check the hatch seals, window, wiper area, anything back there. Climb inside and have a spouse/friend use a hose and spray it down. have you friend focus the spray on the likely areas.
Getting the water out merely requires a shop-vac, and some time. Pick a sunny day and leave it open to air when you’ve got it as dry as you van get it.
Take off the inside trim panel on the van. Go to a carwash and have a friend shoot it with high pressure water. This will hopefully help you figure it out. I would suspect the rubber body seal around the hatch or the one on the body needs to be replaced.
Regardless of the good suggestions, you’ll have to go to a competent auto glass replacement business to get it dealt with. At that age, the worse case could be a rusting frame. Are there any telltale rust bubbles around the rear window frame/gasket junction ? If so, the entire hatch may need to be fixed by body shop or replaced by a junk yard serviceable one.
Best case problem IMO is a door/hatch frame and not window gasket which may be all that needs to be dealt with.