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Rain/water coming in through Firewall.

47K views 192 replies 36 participants last post by  thebroncodude 
#1 ·
OK, I know about the crack issue with the B-Pillar and rain gutter on the Bronco. I've got seam sealer to fix that problem. During the rains today, I noticed that I have water in my floor board. I kinda traced it to behind the covering and the firewall on the drivers side.

Is there a know weak point or some place I need to look specifically to track the entry point? Without tearing apart my entire dash.

Thanks
 
#63 ·
Interesting. After I had to replace the pedal bushings the other day on mine, I noticed that there really didn't appear to be much of any kind of sealant around the brake booster and firewall. There was however, a VERY thin rubber gasket around the clutch cylinder and firewall. I'm thinking that I'll be creating a gasket for those areas again sometime soon after I fix some other minor issues.
 
#64 ·
The gasket between the booster and the firewall was actually one of the first things I addressed. Pulled the booster and put a healthy coating of RTV in place of the dried out gasket. It's possible that area was a problem, but from what I can tell, my current leak is coming from higher up.
 
#65 ·
It looks like its leaking from the clutch plate but you already sealed it. Run a hose on the area and see where it produces a leak.I'm currently chasing a small hard to trace leak from the upper left firewall area.it won't show up if I run a hose over the outside,only under prolonged. Periods of heavy rain.
 
#66 ·
Can't see how mine would still be leaking from the clutch plate, the number of times I've resealed that area would lead me to believe that even if I still had a leak there it wouldn't be in the same exact place and my leak continues to come from the same spot.

I'm going to take a hose and run on the windshield and see what happens.
 
#68 ·
Per this thread where I had my windshield replaced, I thought my leak was fixed..unfortunately, this past week we had some heavy rain and there was the puddle again under the drivers floor mat..

strange thing is this time the padding again the firewall was not wet as it was before, so I'm guessing the water is coming from a different place..just took these pics..

This is where the brake booster comes through the firewall you can see what looks like evidence of water on the backing plate. A while back I had pulled the booster and sealed it up with some RTV. The strange part is it looks like there is rusting metal inside this rubber boot. Wondering if there is a way water could be coming through here...





 
#71 ·
I really don't want to have to tear the dash out..especially for a leak this small..

still betting on window. either hi or low. it can channel all the way.
window or windshield?? I just had my windshield replaced so I would hope that's not the problem.
 
#75 ·
no, it was done by safelite in my driveway while I was at work..I'm making the assumption that the mating surfaces were cleaned thoroughly.

The plunger rod of rebuilt brake boosters doesn't have a special coating so it will rust if exposed to moisture. Can you remove your firewall insulation? doing so will help isolate the problem.
It is possible that the windshield is leaking. Who did the repair and did you watch them? I had my windshield replaced when it cracked and the replacement job was terrible, not only does it look like crap but there are visible gaps in the sealant. At least they're on the bottom so it doesn't leak every time it rains but if I drive in heavy rain I get water dripping from the heater box.
Just because It was replaced doesn't mean it was done right.
Yes I've removed most of the insulation to try and see where it's coming from. Didn't get a chance to check while it was raining since I thought it was fixed from when my windshield was replaced..guess that's was not the case..I did notice there was a copious amount of adhesive used..definitely not pretty from the inside, but there aren't any visible gaps..I really don't think it's the windshield though.


remove the cowl and the body sealer probably pulled up. Mine did that, pulled up like a big funnel.
not sure what you mean..I already pulled my cowl and coated the whole area with a flex seal type product. it didn't do anything.
 
#73 ·
The plunger rod of rebuilt brake boosters doesn't have a special coating so it will rust if exposed to moisture. Can you remove your firewall insulation? doing so will help isolate the problem.
It is possible that the windshield is leaking. Who did the repair and did you watch them? I had my windshield replaced when it cracked and the replacement job was terrible, not only does it look like crap but there are visible gaps in the sealant. At least they're on the bottom so it doesn't leak every time it rains but if I drive in heavy rain I get water dripping from the heater box.
Just because It was replaced doesn't mean it was done right.
 
#77 ·
This is one of those nagging problems that I've been battling with for what seems like forever..

Anyway, I decided to try and get a closer look at things while it was raining and I am pretty sure that I've narrowed down the problem area.

The water is coming in from somewhere between where the steering shaft goes through the firewall and/or another leak from the hole I drilled through the clutch blank to run wires..

This is the pic of how I ran the wires through the firewall. Got a piece of threaded PVC and cut a hole to fit.I was able to fashion a grommet from an old air compressor foot pad.



From what I could tell the water was landing on the threaded part and making it's way drip by drip into the cab..I took some of this putty like substance called duct sealer and ran a bead around the outside of where the threads go through the firewall..It's been raining pretty hard over the last day and a half and it seems to have done the trick..

If you are having the same problem and your clutch blank is still in place, another area to check is the steering shaft plate. I pulled mine just for grins and it didn't look like there was anything sealing between it and the firewall.
 
#79 ·
I give up..:whiteflag floor board was wet again..:banghead

Had pretty steady rain off and on from last night through out the day. Went to check something and noticed the water pooled up again..dripping from here.



you can see the rivulet of water in that notch to the right of where the steering shaft passes through the firewall.

I checked the cowl again, there is no where it could be leaking from there, so the leak has to be coming from higher up..I'm wondering if there is a seam or something in front of the windshield where it meet the bulkhead that the water is dripping through..I can't see it being the windshield itself since it has been leaking in the same spot before and after it was replaced..

I'd like to pull that lower trim piece around the windshield and see what's under there, but I'm afraid I'll destroy it..
 
#80 ·
I give up..:whiteflag floor board was wet again..:banghead

Had pretty steady rain off and on from last night through out the day. Went to check something and noticed the water pooled up again..dripping from here.



you can see the rivulet of water in that notch to the right of where the steering shaft passes through the firewall.

I checked the cowl again, there is no where it could be leaking from there, so the leak has to be coming from higher up..I'm wondering if there is a seam or something in front of the windshield where it meet the bulkhead that the water is dripping through..I can't see it being the windshield itself since it has been leaking in the same spot before and after it was replaced..

I'd like to pull that lower trim piece around the windshield and see what's under there, but I'm afraid I'll destroy it..
Do it. just pry up on it with a small screwdriver or pick wrapped in a rag until you can grab it with your hand. My truck is staying dry for the most part but the carpet on the drivers side by the door jamb still gets a little damp (not soaking wet usually, but damp) when it rains hard alot.
 
#84 ·
Luckily there is no rot in my cowl anywhere..I've seal it pretty good to with the leak sealer..

I wonder if, maybe there's a seam under the fresh air intake and it's maybe mimicking the higher area closer to the windshield. Try having a hard look under that piece first for any cracks that might need to be sealed and even seal over areas that may still look OK.

edit.
OK, never mind. I reread the other post and you'd already looked under the cowl again. It looks like something that's eventually going to require removing the dash for so you get a clean look at the whole firewall.

I'd hate to have to remove the dash for something like this..I have a feeling if I can get the windshield molding off I'll be able to find the problem.
 
#83 · (Edited)
I wonder if, maybe there's a seam under the fresh air intake and it's maybe mimicking the higher area closer to the windshield. Try having a hard look under that piece first for any cracks that might need to be sealed and even seal over areas that may still look OK.

edit.
OK, never mind. I reread the other post and you'd already looked under the cowl again. It looks like something that's eventually going to require removing the dash for so you get a clean look at the whole firewall.
 
#85 ·
This is strange, the leak has stopped again...and it has been raining pretty solid since late yesterday afternoon. I had tried to remove the molding around the windshield to take a look at the seam there, but couldn't get the clips to release, so I gave up rather than breaking them..what I did do was RTV around where the steering shaft plate goes through the firewall. I'm not sure if it was a coincidence or what, but it stopped leaking after I did that.
 
#86 ·
update to this thread..I believe I finally found the source of my leak..doing some rust repair and cleaning up the rain gutters, this is what I found on the drivers side...

There is a crack right in the corner near where the gutter meets the windshield.



here is an up close shot of the crack..



Pfun had suggested the rain was running down the a-pillar and to the firewall..based on what I'm seeing here, I'd say he's probably right. anyway, no way to know for sure until I get it closed up and it rains again, but hopefully this is it..
 
#87 ·
so it rained all day yesterday...and just as I feared, the leak is still there. I was able to lay down on the floor board and watch the water trickle in..So, it was definitely not the crack in the seam at rain gutter because that's been completely sealed ...



and, it was not this, which I thought might be a problem, because it looked like there was a gap which is sealed up as well...





while I was down there I sprayed a decent amount of that flex seal stuff in a can along all those seams..maybe that will help.

frustrating because I feel like I'm back at square one..It has to be coming from somewhere near the base of the windshield..Going to pop the bottom trim off and hit it with some butyl sealer to see if that will do the trick..otherwise, I'm out of guesses at this point..

this was a good thread on the FTE site with some suggestions of other areas to look at..I think my problem could be that lower drain hole...

http://www.ford-trucks.com/forums/901941-cowl-water-leak.html


 
#88 ·
have you tried pulling the cowl off and checking the sealer in there?

oops... Just saw the previous posts. I guess you have. I have one that's almost identical to what you have. I had one on both sides and was able to fix the passenger side by resealing the cowl area. I still can't figure out the drivers side and we haven't had much rain here to figure it out. I'm hoping you find it!
 
#90 ·
update, so it rained again yesterday pretty much most of the day although not as bad as it did over the weekend. Anyway, I wanted to see if the leak was there or not, and miraculously it wasn't....now I'm not sure if the rain wasn't hard enough to cause it to leak, or if the sealer I sprayed from the inside worked..either way, I'm going to pull the cowl again put a better coating of the sealer in there.
 
#91 ·
We had more rain, and guess what? The leak was still there...So, I pulled the cowl off again and inspected the trough...I'm assuming the seam where the water is leaking from is on the right hand side, but I couldn't see any visible cracks..clearly the first application that I did with the flex seal wasn't sufficient...



This time, I made sure to apply a generous coating of the material...



For grins, I pulled the windshield trim and found this small hole, which I'm pretty sure is there to drain water into the trough .it was a little clogged up with debris, so I cleared it out, and while I was there, I also put a bead of silicone in that lower gap between the windshield and the body.



fast forward to yesterday...it poured rain, almost 2 inches..when I got home I checked, expecting to find a puddle of water again, nothing from the firewall...unfortunately, I had left the wing window open and it had a puddle around the window seal and down at the base of the b-pillar...not a big deal since I had the drain holes open there..seems like I may have finally fixed this problem...
 
#94 ·
guess it was wishful thinking..we had a pretty good storm earlier this week..



and this was the floor board...it was completely soaked...



I'm having a windshield company come out and replace and reseal the windshield again. this time I'll be there when they do it to make sure the old material is removed.
 
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