Many times people complain about leaky trucks in one way or another, be it liquid found on the passenger side floor, or water found in the rear. The main thing is it is annoying and we want to fix it. And the hard part is trying to find where it is coming from.

The first step is determining approximately where the leak is, passenger side floor, driver's side floor, rear hatch area, rear seat area etc. Then if you determine that it is the passenger side floor, and it seems to be wet all the time, not just when it rains, then you probably don't have a leak in the body, most likely your heater core has started leaking coolant. To check this, remove the heater core cover (plastic panel below dash on passenger side), the heater core is there and very easy to replace. Check your repair manual for further details.

Here are the common areas:

1. Cowl Area or Windshield conrer

2. A-pillar/roof joint/drip-rail

3. Side-glass seals

4. Rear drip rail

5. Area behind top of rear hatch

1: Cowl vent. This is mainly a problem on the first-generation (84-88) bronco II. Leaves and other debris will clog the drain vents and will cause moisture to sit and create rust holes. Symptoms: Wet front carpet, water in glove box. If caught in time, it is possible to remove the access covers under the hood and spread seam-sealer in the holes, but if its a fairly large hole, the fenders have to come off, the cowl panel has to be removed (lots of spot-weld drilling) and the rusted metal has to be replaced. I should mention this isn't as much of a problem on later (89-90) bronco II's because the cowl was changed from slots to a "mesh" pattern to prevent most debris from entering.

Note that on the inner side of the fire wall, in the passenger compartment where the bottom corners of the windshield is, is a very common area for water to leak in. This area tends to rust and allow lots of water in when it is wet. It usually happens first on the passenger side, then later on the drivers side rusts. In order to access this area the dash must partially be removed. The old sealant will have to be removed, and all rust ground away, then new sealant installed. See photos below:

2: A-pillar/roof joint/drip-rail. This is a VERY common leak on BII's no matter the year. The seam sealer gets brittle with age and either cracks or crumbles away leaving an open seam. It can also be hidden behind the windshield trim. Symptoms are wet floorboard and a drip from the headliner just past the windshield. A temp fix is to smear silicone down in the cracks and joints with your finger. This will stop the leak for a little while until the rest of the seam sealer cracks. Best fix is to dig all of the old seam-sealer out and put new sealer in.

3: Side-glass seals. These are usually easier to spot as most of the time the leak will run down the inside of the glass when it rains. Symptoms are wet cargo-carpet and streaks on the inside of a foggy window. The fix is pretty simple, just time consuming. Basically you have to remove all of the interior trim for that side of the truck, un-bolt the glass, and with an assistant work a screw diver under the glass enough to run a piece of piano wire or some wire thin enough to cut what's left of the seal. DO NOT try to force the glass out or else you will shatter the glass, end up with cuts, have a nice open hole in your BII, and have to drop a good chunk of money for a replacement (and they're not cheap.)

After the glass is out, clean the sealing surfaces as best as you can, and apply some "tar ribbon" around the sealing surface of the glass. You can get the tar ribbon at just about any automotive store or windshield shop. Everything else is reverse of removal.

4: Rear drip rail. Why ford put these on is beyond me, but they too can cause leaks. Basically the same was as number 2. Seam sealer dries, cracks, leaks. Symptoms are wet cargo carpet. The fix is the same as number 2's.

5: Area behind top of rear hatch. Once again, seam sealer is the problem, but this time there is a bunch of it. symptoms are wet rear headliner and wet cargo carpet. There really isn't a good temp fix for this because there is so much seam sealer that you'll spend more time smearing silicone over it than it would take to break all of the seam sealer out and replace it.
 

All of the leaks above can lead to rust that puts the strength of the body in question. Rust around the front and rear body to frame bolts can be a problem, especially in a collision. The best way to fix it is to catch it before it starts.



Tech page written by Ben Hart & Harry Rathien.