I was wondering that same thing at one time, brake booster, but the foam on the firewall does not feel wet up that high to me. I have snapped a photo of mine for comparison, hopefully you can see the seal that does appear to be there, although it does seem aged.



I also finally got the cowl off and made sure it was clean under there which it was fairly clean. I took a hose and let it run in there and never saw any signs of a leak inside.

Still investigating although I am getting annoyed at this.

I may get some talc and go that method and see if it works...but my truck is white.

 

ACarbone624, if your seatbelt is wet after hard rains, it probably is the door gasket seal. It may not be that it is bad though. You might try adjusting the pin for the door catch (part mounted on cab not door). You can adjust this in out up down. If you decide you want to adjust it, just loosen it slightly and tap it inwards a hair. I did that on mine along time ago.

RedRocket, thanks for the picture. Mine just looks like it doesn't really even have a seal on it anymore. Maybe it shrank or something. I too have had the cowel off when I replaced all of the wiper arms and linkages etc. I did clean out a little bit of crap down where it drains out on the driver side, but it wasn't bad. I really don't think its the cowel thats leaking. Someond did mention that there could be a seam in the sheet metal under there that was prone to leaking on the older trucks, but I don't think it applies to ours (92-96). I have run the hose in the cowel and didn't see evidence of a leak inside, but maybe its only when I go to the high pressure car wash or an extremely heavy down pour or rain occurs. I don't know, but I sure don't want my floor pan to rust out. As of right now it looks fine under there. If it keeps getting wet, it will evently cause damage.

I am probably going to go ahead and replace the door seals, since I already have them.

 

My 89 F250 had the same leak, what I did was pull the cowl off and cleaned the area out and used bed liner paint to seal the area up. That did the trick. that seam has a sealer which is kinda like foam, that stuff will wick water all over the place once the factory paint was cracked off. I took the whole dash assy out as I though I had a rust hole in that seam. Kinda intresting watching how the water was wicked from the passenger side area to drivers side before dripping over the break pedel. The years of dust showed the water trail really good.

 

That is a great idea and I am going to do this to see if that fixes my leak. Even though I did not see "fresh" water inside the cab when I did my cowl leak test, it may just do the trick. At least if it doesn't fix it, then I know I will need to be looking elsewhere. But, I fear my leak may be traveling as you have mentioned above and maybe my leak test was not sufficient. I know TexasGuy said 92 - 96 is not prone to the same kind of leak from the flex in the cowl area but I am getting desperate to get this fixed. I still have carpet and if this continues to stay wet, mildew and mold will be next.

Other things I tried was to remove the wheel well liner and see if there was any signs of water getting in. I did not seem to find anything that looked suspect. I have not tried the talc test yet but it almost seems as it wouldn't work inside the cab because of all the foam that is difficult to remove or move without destroying it. That foam, the vertical foam attached to the firewall that ends at the lower firewall ledge seam, on mine is very wet right now, on the bottom 4 inches of it. Wet enough that if I compress the foam, water runs out of it.

 

How about where the steering column goes through the firewall?

On my gen truck the underlayment was not glued to the floor or firewall. I don't know about the '95.

Yes, dust or spray powder it works the same. If yours is wet now this method won't work for you.
One place I did get rust through that was hidden from the underside was in the boxed in corner at the lower rear of the fenderwell. Again, this is on the '87 body so I don't know about yours.
Just some places to look.

 

When I used the bed liner paint, I got a quart of that Dupli-color bed liner paint, I used the whole jug up in the cowel area, Its messy, but once a few good coats are in there, its sealed up really good. The only other thing I have seen before is water leaking from the windshield. If that's the case, the windwshield will have to come out and be resealed with proper windsheld adheasive. DON'T use any silicone to reseal a windshield, thats only a temp fix at best as the silicone will dry and crack letting water back in. it also causes rust to happen much faster for some reason...

 

On the carpet issue, take it out before the mold/musty starts up. I took mine out and used a pressure washer on the wide fan spray, little landery soap. you should of seen the crap that came out of it! Let it dry in the sun for a week, flipping it over couple times. It should come out looking clean and no smells. Also having the carpet removed makes looking for leaks much easyer too.

 

I got a spray can of the Dupli-Color at Napa yesterday...on sale for $6.29 for anyone interested if you can get the same price. I wondered if I should have got the roll on stuff but they only had a gallon size. Anywho...got it all nice and thick covered in the cowl area.

I also noticed that the rubber seal that attaches to the cowl has a taped on seal so the water coming off the hood does not run straight down the firewall on the inside of the engine bay. Since I had taken this off in an attempt to clean up the truck when I first bought it and TexasGuy also must have taken this off to replace the windshield wipers and linkage I thought maybe I would try and seal that better. At least keep water from running straight down the firewall and maybe in somewhere I have not be able to identify. Who knows??? It is worth a shot although it won't really fix that actual place it is leaking into the cab if this is part of the problem. But, the tape on seal was a mess from me removing that piece. Just a thought.

I should pull out the carpet and clean it like that. Would be nice to get it cleaned up from the previous owner anyway...he had kids and there was ceral and crap everywhere. How difficult/time consuming was it to pull out the carpet?

 

You just pull the seat and seat belts(takes a big torex bit on the belts) Hopefully the bolts aren't rusted in place. the trim that holds the carpet in the doorway may be a pain as the phillips heads most likely are rusted. In about 30 min you can do it. best to get a helper with the seat, but if your like me, just fight it out! After pulling the carpet I just put back the seat and seat belts to make it driveable(plus nobetter place to store that big seat!)

Used that spray on stuff, I bet that was fun and messy!! rolling the bed liner paint on was somewhat messy. At least it don't stay on your hands long!

 

I just got back from a business trip where I did not drive the truck. Truck sat parked out in the rain while I was gone. I have not resolved my leak yet.

I did have the carpet pulled up out of the way and I could see some drops just below where the parking brake foot lever is but the foot lever did not get my hand wet when feeling around on it. The investigation continues.

My best bet is to remove the carpet now until I get this issue resolved. Thanks for the tips on the removal. I absolutely despise the thought of dropping the entire dash to find where this leak is coming from. I may be forced to do so as I can't live with this leak.

 

I have a 87 truck with the dash pulled out, I'll try to get some photos up(if the camera works). Looking over where the parking brake bracket is, there are 3 seams comeing together right over it. I check the ECU which is right next to the bracket to see of it got wet to be safe. You may want to get a quart of that bed liner paint, and "pour" it down the water channels. thats what I did on my 89. Other possiblity is the door seam/seal area.

 

Ok, I made a Gallery(under my handle) with the photos of those seam areas. This should help you out Red Rocket, Its a pain to get the dash assy out! Need more photos let me know of the area. Its of a 87 F150 but all cabs of 87 to 89 are the same execpt for the seam filler, the 87's used a hard rubber, the 89 used a foam type(more leak prone). The newer trucks are probly much the same till 94???

 

VERY cool! Thank you. Seeing those pics and hearing that is what you did makes me feel confident that using the approach of pouring the truck bed liner stuff down that area may seal everything. Obviously I can't get the spray in that area but having a quart and then pouring it down the natural route chosen by liquid may seal that area for good. I will do it tomorrow if the weather holds out.

 

Well, I sealed up where the power brake booster meets the fire wall with stip caulk, but the leak is just the same as it was before. I am starting to think that Jason was right about the door seals or that I have the problem mentioned by Eddiec1564.

I am about to replace me door seals since I already have them. Has any one replaced them before? I have a delima. There is some rust on the lower lip that the gasket sits on on both sides. The passenger side is minimal, but the driver side is pretty bad in the middle. When I lifted up the gasket to inspect a 2 inch peice broke off in the middle. What sould I do about this. Also, what should I do about the rust in general? I have a product made by Kleanstip that is rust remover and another that is rust converter. Should I try either of these or just bite the bullet and buy some Rust Bullet?

 

On a side note, put cardboard where the paint will flow out of the truck, that stuff will not come out of a concret driveway!

I used a rust converter, it changes rust to a hard black primer type paint(?) I first wire wheel out most of the heavy chunks then coat the rust area. After I clean the area with paint remover or ect and paint over it all.