This is my first post, so I apologize if I've broken some kind of etiquette or rule for new guys. I am not a mechanic; nor am I particularly experienced or skilled at fixing stuff. Nonetheless, I recently had an awful experience locating and fixing a few water leaks, and I was able to use this forum (and others) to learn very helpful information from others' experiences. This post is an attempt to "give back." I hope that someone else may benefit from my experience in the event that they have to track down their own water leaks.

Here we go...

I got a new-to-me 2008 F150 King Ranch in November of last year. Shortly after getting the truck, I began to hear the sound of moving water during acceleration or deceleration. It was always from the passenger side floor board. It didn't happen every day. The timing seemed very inconsistent. I never saw any evidence of water intrusion, so I didn't worry about it.

By complete coincidence, my third brake light started leaking around the end of December. (There are plenty of threads addressing that issue, so I won't get into that fix.) I immediately fixed the third brake light and set to drying out the water that had leaked into the truck.

In the process of drying out the truck, I removed the plastic trim pieces / plates at the bottom of the door frames. I don't know the technical name of the pieces, but your foot would step on top of these plates when getting into or out of the truck. Under these plastic plates, on both the driver side and passenger side, there is a channel that runs the length of the cab, front-to-back. A thick bundle of wires is housed inside each of these channels.

When I opened these channels, the driver side was only slightly wet. The passenger side was completely full!!! This explains the sound of flowing water! I pulled the rubber grommets (drain plugs) in the channels and dried everything out.

After the next rain, I saw water gathering in the passenger side wire channel. The water was pooling at the front, first. I confirmed that the third brake light was fixed. Now, I set to finding the second leak.

I removed the kick plates and exposed the base of the A-pillar and the junction box. All of the carpet and padding was soaking wet. (Because of the floor mats, I had never noticed the carpet was wet.) I pulled back all of the passenger side carpeting and padding, and I propped up as much as I could to promote airflow. (This is important! Assuming it's not too late, you must completely dry out the carpet and padding as soon as possible! The padding will not dry out unless it is raised off of the floor.)

With the next rain, I saw water slowly dripping into the front of the wire channel from behind / under the junction box. At the base of the A-pillar, there is a large rubber boot that plugs a hole in the A-pillar. I removed that rubber boot, exposing the inside of the bottom of the A-pillar.

The A-pillar was filled with standing water!!! Somehow, water was leaking into the inside of the A-pillar. When the water level reached the rubber boot, it would pour over into the cab, eventually pooling in the wiring channel.

I checked a variety of possible leaks.
1) I don't have a sunroof, so sunroof drains can be ruled out.
2) The satellite antenna was properly installed and showed no signs of wear. I also removed the A-pillar column trim (also known as the "oh schlit handle"). There were no signs of water intrusion.
3) The windshield showed no signs of improper installation, and I was fairly confident that the windshield, itself, was not the source of the leak.
4) I confirmed that the third brake light was still fixed.
5) Through a water test (starting at the bottom), I confirmed that I did not have any noticeable leaks through body seams in or around the fender - firewall area.

[Pro tip: don't try to perform any kind of water test when the temperatures are near freezing. Even if the air temp gets above freezing, several surfaces on the truck will not get above freezing. If you forget this tip, don't worry; you will quickly draw the same conclusion on your own.]

And finally, number 6): windshield stop. This was the source of the leak.

This is a picture of the windshield stop before the fix.


This piece is a piece! It is very fragile and is easily damaged. The foam gasket on the bottom is laughable. I can't imagine the confluence of pure stupidity that allowed this piece to be a part of this truck.

From what I can tell, the windshield stop is intended to be used as a spacer to properly install the windshield. This piece is way too flimsy to support the weight of a windshield. I can assure you, if your windshield was properly installed, this piece serves no useful purpose other than 1) receiving the pin for the wiper cowlings, and 2) preventing (or allowing) a water leak into your A-pillar.

If this piece is loose, it's the source of your leak. If you had the windshield replaced and they didn't use a new windshield stop, this is the source of your leak. If you yanked on the wiper cowling pin too hard, this is the source of your leak. Even if the thing looks perfectly normal, it's probably the source of your leak.

If this is your situation, remove it immediately! As long as you don't displace the windshield, just pull it out as best as you can. Parts of the windshield stop will be wedged under the windshield. That's ok. Just remove it slowly and deliberately.

Don't worry about trying to remove it without damaging the piece. It is impossible to remove the windshield stop without permanently damaging the clip on the bottom. It's also impossible to fix it without taking it off. Just get it off. After you remove it, clean all the surfaces and carefully place a 2"x2" piece of duct tape over the hole. Now, you can take your time getting the replacement pieces. (Alternatively, if you still have leak after placing the duct tape, you should probably find the source of your second serious leak!)

A new windshield stop from Ford costs about $7.


How to install the new windshield stop....

Remember, these parts are usually installed before installing the windshield. Assuming that you don't want to replace the entire windshield, you will likely have to modify the new part.

IMPORTANT: WHEN FITTING THE PIECE, DO NOT PRESS ALL THE WAY DOWN UNTIL YOU ARE READY FOR FINAL INSTALLATION. Once this piece is pressed into the hole, it WILL NOT come back out without breaking the clip on the bottom.

1) Cut as much as needed for the new windshield stop to clear the windshield for installation.

This is a picture of a new windshield stop without modification.


Remember, this piece doesn't support the windshield anymore. Cut as much as needed. At a minimum, you will likely have to cut the four "folding tabs" (two on each side). You will also likely need to cut the middle "stem" that sticks straight up from the top/middle.

In addition to cutting the middle stem, I found it necessary to file down and sand the plastic lip under the stem.

Cut or file off as much you need. Just check your progress as you go. I would cut a little bit, then check for clearance. Lather, rinse, and repeat.

Remember: when you are fitting the piece at this stage, DO NOT press it all the way into the hole.

2) Once you have cut enough to fit the piece past the windshield, break out the RTV. I used basic clear RTV silicone. (Because of the angles, I used a bendy drinking straw duct taped to the end of the silicone nozzle for better access.)

First, I put a small bead at the base of the windshield. Remember the tabs and stem that we cut off of the new windshield stop. The bead at the base of the windshield is to seal where the tabs and stem would have gone (had they not been removed).

Second, I put a small bead over and around the hole where the windshield stop will be inserted. It's a small hole, so even if you're trying to just do the edges, you will likely cover the entire thing.

Third, while the first two beads were setting up, I forced RTV into and around the gasket on the bottom of the new windshield stop.

This is a picture of the bottom of the windshield stop. Note the crappy foam gasket.


Fourth, once you have enough RTV in the nooks and crannies of the bottom of the new windshield stop, now it's time to place it. Watch your clearance. Just remember, you only get one shot at placing this thing. You might hear a very faint *click* as it snaps into place. If you don't, don't worry about it. You can only press it so far.

Fifth, give the RTV a little time to set up before putting the final beads of RTV. For me, I probably went way overboard. Honestly, I could give a damn. I was ready for this process to be finished. There was no way I was going to be short on RTV.

This is a picture of the new windshield stop after RTV. It's not pretty, but it's not leaking, either!




The good news: this was the source and fix for the most serious leak.

The bad news: While verifying that I fixed this leak, I found two more extremely minor water leaks (also in the A-pillar). I will write another post tomorrow explaining how I found and (mostly) fixed the other two minor water leaks.


A couple of notes:
--Believe it or not, this is an abridged version of the bigger story. I wasted a lot of time trying to find the source of the leak.
--To do this job correctly, you need to replace the windshield stop with a new piece. I took the truck to a "water leak specialist." They tried to glob RTV all over the windshield stop in hopes of just choking off access to that hole. No such luck. It took all of 7 days for water to find a way back through the hole. That was the point when I had to completely remove the windshield stop, out from under a lot of cured and un-cured RTV!
--I didn't cover the process for removing the wiper cowlings. This is necessary, but there are plenty of threads on this process.
--If you're going through the process for one side, I would suggest doing the other side at the same time. The new windshield stop only costs $7. Buy enough to do both sides. You might also want to buy an extra one for when you accidentally press it in before you're ready. (Ask me how I know!)
--Go ahead and remove the glove box.
--Remove the other rubber boots that block the access holes to the A-pillar. Sometimes you have to get a flashlight in there at a different angle, and those access holes become necessary.
--If you have clumsy potato hands like me, the A-pillar is not a friendly environment. I had some limited success with placing flashlights inside the A-pillar and then maneuvering a mirror at the bottom, looking up. Even then, I had a hell of a time.


Like I said, I will try to write another post tomorrow explaining the other two minor water leaks that I found after this one.

In the mean time, I hope someone may benefit from my experience.

More to follow...

 

nice write up. my drivers side floor gets wet sometimes and I cannot figure out the leak. I am going to be checking this out. thanks

 

This was also posted on the original thread in the 04-08 forum.

Thanks for the comments.

Sorry for the delay in posting the remainder of my story. I will try to make this installment more concise.

Part II ...

As I said, in the process of fixing the serious leak, I discovered two other minor leaks.

1) Door hinge mounting plate. (I have no idea if that is the correct technical term for the part.) As I alluded to above, I spent a great deal of time with mirrors and flashlights looking around the inside of the A-pillar. In doing so, I noticed a drop of water that had collected on the bottom of the interior door hinge mounting plate.

On the outside of the A-pillar, it is easy to see the door hinges (top and bottom). The part of the hinge that attaches to the A-pillar is a mostly-flat plate / bracket. This is what I am calling the exterior mounting bracket. That exterior mounting bracket is attached to the A-pillar by three or four bolts. On the inside of the A-pillar, the bolts are threaded through another similarly sized plate / bracket. This is what I am calling the interior mounting plate. I noticed the drop of water on the bottom side of the interior mounting plate, on the inside of the A-pillar.

If you look on the outside of the A-pillar, at the exterior mounting bracket, you will notice the edges are flared out and away from the A-pillar. On the top of the bracket, this forms a small gap that collects dirt and water very easily. Most importantly, any water that lands on this gap is channelled TOWARDS the A-pillar, in between the A-pillar and the exterior mounting bracket.

In my case, over the years, water and small particulate had accumulated in this gap. My working theory is that the water had eventually corroded just enough of the surfaces of the exterior mounting bracket and the A-pillar. The water finally found its way to the mounting bolts, and then it seeped through the bolt holes. Once through the bolt holes, it slowly seeped between the A-pillar and the interior mounting plate. Thus, water drops on the bottom of the interior mounting plate.

The fix...

In a perfect world, you remove the hinges, clean the surfaces, remount the hinges, seam seal the gap between the exterior mounting bracket and the A-pillar, and re-hang the door; all with perfect alignment and no out-of-pocket costs because you're a badass.

In my less-than-perfect world, I cleaned the gap as best as I could with water and a toothbrush. I cleaned the surfaces with rubbing alcohol and let dry completely. I then busted out the clear RTV silicone, duct taped the bendy straw to the end, and set to putting a bead on the top of the exterior mounting bracket.

I put a healthy bead of RTV on both the top and bottom hinge brackets. You will notice that exterior mounting bracket extends all the way under the front fender. (It's not much, but it's in there.) The bendy straw was necessary to reach all the way to the front of the bracket.

With the RTV in place, water and dirt can no longer collect in the gap, and everything is channelled away from the A-pillar, rather than in between the bracket and A-pillar.

I haven't yet done the same procedure on my driver's side, but I will very soon.

If I had to guess, the vast majority of trucks will have this same very minor water leak, but I doubt many people will ever notice it. It is unlikely that this leak would ever allow water to collect at the bottom of the A-pillar. In fact, the leak is so minor that it would probably be imperceptible, unless you were specifically examining the inside of the A-pillar (something most people will never do).


Note: when I first saw the water under the interior mounting plate, I thought it was just condensation from the cold water hose running on the outside. If you use a water hose to check for leaks, you will most likely have condensation form from the temperature difference. In my case, the tell-tale water drop was visibly distinct from the surrounding condensation.



Sorry for being long-winded.

I will try to post the last installment soon...

 

Last installment...

After fixing the windshield stop and "sealing" the door hinge mounts, I still had a slight problem. After an automatic car wash, I noticed a small amount of water in the bottom of the A-pillar. This was a very small amount of water. It was equivalent to approximately 3 drops of water from an eye dropper. Nonetheless, I still had a leak.

I was pretty sure the door check assembly was the culprit, but I needed confirmation. More importantly, I needed to know that my other two "fixes" were actually fixed! After a little more internet research, I came up with a detection method. (I really wish I had thought of this sooner.)

I bought a small UV light from the parts store. It was a low-powered pen light because I needed it to fit inside the A-pillar. A brighter light would have been much more helpful. Then, I bought two normal size yellow highlighters. I filled a 5-gallon bucket with water, and I cut open the highlighters and dumped the ink cartridges in the water. (I completely opened the ink cartridges, exposing all of the little fibers.) I let the bucket sit over night, but I'm sure less time would suffice.

The next night, after dark, I used an empty water bottle to slowly pour the water all over the A-pillar. One bottle at a time. High and low. I made sure to slosh some of the water between the fender and the door. I made sure not to open the passenger side door, even after I finished pouring. From the driver's side, I crawled into the passenger side floor board. (If any of my neighbors saw this spectacle, it must have been quite the sight.)

Using the mirrors and my UV pen light, I saw that the green/yellow water had dripped down from the door check assembly.

Thus, the second minor water leak...

2) Door check assembly. The door checks on the front doors are poorly designed. On every other door I have seen (not an exhaustive survey), the door check arm is permanently affixed to the A-pillar, and it moves freely into and out of the door, itself, as the door is opened or closed. Because of the design and function of a door check, it impossible to completely seal off the hole through which the door check arm moves. If hole is in the door, itself, any water intrusion is easily channeled out through the bottom (the same as any water that enters through the window). Doors are built to handle water intrusion. A-pillars are not.

On my truck, the front door check arm is permanently affixed to the door (not the A-pillar), and the door check arm moves into and out of a hole in the A-pillar (not the door). When the door is completely closed, there is a flimsy rubber gasket (almost shaped like a small cup) that is designed to seat around the hole.

Two problems: 1) even if this flimsy rubber gasket is brand new and properly seated, it is not a quality seal; 2) the gasket distorts and dries with age.

And another problem: the door check assembly (the part that gives resistance when you open your door) is located on the inside of the A-pillar. What kind of "gasket" is between the door check assembly and the metal of the A-pillar? That's a good question. It's the same low quality foam material that is found under the offending windshield stop (also around the infamous third brake light).

I think it is likely that the vast majority of trucks will exhibit similar water intrusion through the door check assembly. And, just like the door hinge mounting plates, no one will ever notice it because the amount of water is so small.

I almost replaced the door check assembly, but it would not have changed the inherently flawed design. Eventually, the same problem would develop again.

I also had to consider what would be an "acceptable" amount of water intrusion. To put things in perspective, the amount of water that was leaking through the door check assembly was very, very minor. I think of it this way: if I open my door during a light rain, I will necessarily have more than a few drops of rain enter the cab of the truck. The same thing when I get in with wet boots. This happens all the time. It's never an issue because it will evaporate quickly due to the relatively small amounts.

Rather than replace the entire door check assembly, I decided to "discourage" water intrusion as best as possible. I took some generic silicone grease (not RTV) and completely coated the door check arm, the flimsy rubber gasket, and packed it into the little hole in the A-pillar. (At the same time, I coated rubber boot that houses the wiring from the door (just below the door check arm).)

I am sure that some water will still make its way through, but I am reasonably confident that the volume of water will remain inconsequential.


As I stated earlier, I am not a mechanic, nor am I particularly skilled or experienced at fixing stuff. This is just my experience and what eventually worked for me. I hope it might save someone else some of the frustration that I experienced.