The carpet has been removed. I am getting a puddle of water between the brake pedal and the seat. I don't see water marks from the firewall. I assume it is dripping in. Is this from windshield seal leaking or somewhere else? Any thoughts are appreciated.

Hi Rich - You'll just have to do the old trial and error approach. Get a friend to work with you and your garden hose. Take the nozzle off so you get a good flow with no pressure so the water will flow on small areas at a time. Get inside the car and start having your friend move the hose slowly from one side to another over the roof and then the windshield area until you see where the water is coming in. If no luck, simply move the hose lower and lower all around the car until you see the entry point. Pay particular attention to the window seals on the doors. Don't forget to open the hood and do this procedure over the top of the firewall where the fresh air intakes are, as well as wiper mounting areas, etc. Should take no more than 1/2 hour to pinpoint your source of entry. Then the real fun begins when you stop to fix the leak. Let us know how you make out with this test.

A lot of A/G-bodies rust out along the top of the door sill area, on the floorpan between the seat edge and where the door sill bolts to the floorpan. This causes water splashed up from the road to soak the carpet by the door sill, and then run down onto the floorpans and soak the rest of the carpet. A dead giveaway of this problem is if you find a white powdery substance building up on your carpet right next to, and underneath, your aluminum door sill plates. This is caused by an electrochemical reaction called electrolysis and is the result of the aluminum door sill sitting on top of damp carpet sitting on top of damp steel floorboard.

This is a really tough area to repair because it sits right on top of the frame rails so you can't really get to the area from the bottom to properly seal it. If you could remove your body mount bolts and jack up that side of the body, you probably would have enough room to at least get your fingers and smaller tools in there and perhaps work it over with POR-15 type repair materials.

The other place where you get insidious, hard-to-find leaking, is the vertical seam of the firewall and floorpan that's just outside of the brake or clutch pedal. This is also very tough to get to from the outside but easier than the door sill area. This area was spot-welded together and I suppose used to have factory waterproof goop between the overlapping sheet metal but by this time, that goop has dried hard and allowed water to collect within the overlapping areas, causing both sheets of steel to rust. When you drive down a thoroughly wet road, your front tires throw water right onto this area and it seeps through that overlap and soaks the carpet.

Yes, you could also have leaks from bad windshield seals. One place I found on my '84 Elky was along both A-pillars, where they had both rotted out underneath the glass. This allows rain water to drip down the inside of the A-pillars then down behind the kick panels and onto the floor. Because the A-pillars were rotted, the windshield was no longer solidly supported along the vertical edges and cracked part way up, from the side. I doubt there's any way to repair that except weld in a good A-pillar from another vehicle. Also, note that our Elkies are essentlally 2-door models; they share the windshield with Monte Carlos and other 2-door A/G-body models. This windshield lays back further than that used on the 4-door models such as the A/G-body wagons. That also means the A-pillars must come from another 2-door model, both because of the angle and also the exterior shape is different between the two.

The '60s A-bodies are notorious for having the cowl area at the top of the firewall and bottom of windshield rot away; but I haven't heard of that happening on the later A/G-bodies very often. There are even repop cowls available for those older vehicles and just about every restoration requires replacement of that cowl sheet metal.

Hey I had a similar problem on my elky. I did the hose thing and it endend up being a crack in the box where the fresh air is sealed it up and havent had a prob since knock on wood :D

I think I'm double screwed then Cause it collects in the floor boards up front and behind the seat on my 84 Caballero one hint on mine is the vin plate on the drivers side behind the windshields rusted so I suspect it's probly the seal there not certain though although I have no idea where the waters getting into the back floor pans from any suggestions oh and the metal in the dash also has surface cancer on it too

I think I'm double screwed then Cause it collects in the floor boards up front and behind the seat on my 84 Caballero one hint on mine is the vin plate on the drivers side behind the windshields rusted so I suspect it's probly the seal there not certain though although I have no idea where the waters getting into the back floor pans from any suggestions oh and the metal in the dash also has surface cancer on it too

I don't have a whole lot of experience with these A/G-bodies; but what you're describing does sound to me like not necessarily a firewall leakage problem, but very possibly a windshield leakage problem, either along the TOP (where water can drip into the inside top windshield trim piece and then roll off down the A-pillars onto the floor), or the driver's side A-pillar. As I described earlier, I had a rotted pass side A-pillar which allowed water to drip down right around the ECM and onto the pass floor. From there, it EASILY rolls backward under acceleration and fills the rear floor. To see just how easily, remove the carpet entirely and let water collect in the front floor, then drive around a bit 8O

On the driver's side of my '84, the A-pillar only had small holes but again, they let the carpet to get soaked up front and the excess water would roll backward into the rear floorpan. But in addition, on both sides, it flowed along the underside of the windshield inside the car and rusted the VIN plate as well as other areas at the inside-top of the cowl, including the INSIDE of the heater box mounting surface. That REALLY puzzled me for awhile until I realized how the A-pillar was perforated.

If you haven't already, you might remove your outside windshield trim and check your A-pillars. Mine had been filled in with RTV by a PO and that did nothing to stop rusting since it didn't prevent water from attacking the existing rust; instead, it let the water sit on the windshield frame and go to town.

This is the truck that I recently posted on the For-Sale forum that I'm scrapping, by the way.

I'll check the A Pillars and the window seal upfront but theres something going on in back too cause even when it sits outside for a few days and it happens to rain the back floor boards become a mini swimming pool so I'm at a loss for the cause of this I can't afford to scrap the GMC though theres not alot of 84 Caballeros around to replace it with So I've got trace and fix the problems on this one

Lots of places for the bed to be leaking into the smuggler's compartment then the water can run down onto the rear floorboard. In addition to possible cracks in the sealant between the bed and rear wall of the cab, you may also have holes through the rear winder support structure, especially in the lower channel of that structure. My '79 has lots of those. It also has a crack through the sealant right behind the driver's side of the seat so when I know it's going to rain, I park it facing uphill so water in the bed runs down and out the back instead of pooling up next to the cab and dripping through that sealant.

There can be holes in the back of the underside of that smuggler's cmptmt, too; in the dark, lay a troublelight under that cmptmt in front of the rear wheels then look into the cmptmt. If someone else can press upward on the cmptmt's floor while you look inside, you may find cracks that open up as the body wriggles and jiggles. Do the same for the bed; have someone stand in there and lightly stomp while holding the troublelight over the bed and you look inside for cracks and pinholes.