SPF GT40 Water Intrusion

Water intrusion into the SPF GT40.

This is what I found in over a year and a half working on SPF 2197. Some of the information in this HOW TO article I’ve posted in other threads but hopefully this should cover everything.

This whole thing started with a conversation with Lynn Miner and the problems he had with his car and some of what I will be posting came from his research.

As I see it there are the usually suspects such as the opening around the steering column, etc. those are ease to see and fix. The tough ones are the ones you have to take the car apart to see and get to. Also every pinch seam in the car is a potential place for rust to start, and most of these are in places that are not easy to get to.

As I’m no expert at this I’m sure other people will have better ways of doing this but I’m very happy with the outcome. I’m going back and start at the beginning and this will take more than one post but here it goes.

The Pinch Seams.

I’m not a big fan of the way cars are made where pinch seams are spot wielded together but it is what it is. After seeing pictures of many of the original cars rusted very badly in the sponson and tub area’s I decided that was where I would start. I barrowed some undercoating that Lynn had left over and it turned out to be a stroke of luck. There were two types of undercoating, a waxy one and one that was more like pant but was rubberized. An important aspect of the rubberized pant was that it was an almost exact match to the paint used to paint most of the SPF GT40’s chassis’s. It’s sold by Eastwood’s and is great stuff. I ended up using both types depending on the application.

I hope someone finds a better way of doing this next part but I used a standard large medical syringe. At first I tried getting them through medical channels but they can’t sell them to you without a prescription. You can however buy as many as you want from the local feed store. I did end up with a bigger one than the one in the picture but that's what I started with.

As I knew I was going to waterproof inside the sponson area I started by removing the front suspension and gas tanks which uncovered some very large holes which I’ll talk about later. I first went around the car with syringe and filled every external seam I could find. I mostly worked on the seam the goes around the entire car right at the bottom edge but did every seam I could find. One big one is at the front edge of the tub were the piece of sheet metal is pop riveted on. You have to do the top and the bottom of the seam. I did it more than once as it just kept sucking in the paint. There is also a rubber seal at the top edge just in front of the windshield which I removed, sealed then re-glued into place.

I then did what Lynn had done and drilled small holes into all of the car’s rear compartments that can’t be accessed directly any other way. This included the horseshoe shaped piece that goes around the bellhousing. In my case those areas got treated with the waxy undercoating with the gun and wand Eastwood sells for this job. I did the inside of the sponsons at the same time. Don’t be surprised if it runs out of places that you don’t think it should.

Another place that surprised me was at the lower edge at the front of the foot well. Lynn warned me about this but was still a shock to see the way this area was put together (not very well). Just a little more work on this part would have saved me a ton of time. It’s a big enough issue I’ll be covering this later.

Well this is my first installment hopefully the pictures will fill in for what I didn’t say.
 

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SPF GT40 Water Intrusion Part 2

During the seam sealing and because the front suspension was off the car I started looking into the cavities left at the suspension attachment points. Every one required some sort of sealing. A few were rather minor but some I think you could put a garden hose into and fill the inside of the car.

Although there are holes everywhere the biggest offender was the cavity where the shock and rear pivot of the upper control arm meet. As much as I tried to get some good pictures it just didn’t work. I’ve included some but until you see it for yourself it will not make much sense. I used a combination of the 3M window calk that Rick talked about, asphalt roof calk (it’s black silicon that never hardens) and the rubberized undercoating from Eastwood.
I filled every hole that water could seep into and there are lots of them so just keep looking.

The next problem I ran into was sealing in and around the fake oil tank. The only reason I even moved the A/C unit was to get to the pedal box. But after taking it apart I was glad I did.

Because the entire area is open to rain water spare off the tires and other parts of the car, there is no way to tell where the water will land and/or collect. I figured you plan for the worst and hope for the best. I think I posted something about this already but I have to look at my name badge to remind myself every morning who I am and where I work so sorry if some of this is a repeat.

After the A/C unit is moved out of the way you gain access to a D shaped cover that is just above the pedals. Under its lip is a ¾” to 1” wide foam seal that has a waxy feel to it you don’t want to mess it up if you can help it but what I did when I put it back in place was to roll out a 1/8” or so rope made of the 3M calk and put in the grove around the entire outside lip of the D shaped cover and around the heads of all the screws. You can just see it at the bottom edge of the cover in the last picture. I’m sure I took a picture of it (I take pictures of everything) but at this point I can’t find it.

What I did take a picture of was the seal I made for the fake oil tank cover. At this point all I was trying to do was to direct the water so it didn’t run down the back of the A/C unit and into any of the vents that run between the A/C unit and the dash. The gap is fairly small and consistent and unless you’re looking for it, it pretty much disappears after everything gets put back together.

Well as I sit here having dunk my one drink limit (cheap date) I think I’ll leave any more to the next installment. If you need more info or you just want to yell at me send me a PM or an email or post something to Rick's great thread..
 

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Richard, Knowing this is an older thread (but I'm new to the forum), I'd still like to suggest this: Cosmoline makes Cosmoline Black rust veto. It's an industrial product. I've used it extensively on my E-350 towing van. It is an outstanding product that can be brushed or sprayed. It is a thin waxy substance that will creep into all the nooks and crannies, especially those pesky pinch welds. It has a shiny black finish and will dry completely, so it can be wiped clean and looks like a paint coat. It can be removed easily with thinner. I used a sprayer with a 3 foot hose extension with a 360 degree spray head that can be pulled through hard to reach hollows and is certain to cover the entire area and creep into the crevasses. I am confident this forever will seal these areas from water. I used so much of this stuff in my 63 XKE that I think it might float... And yes, when I got my SPF I was appalled at the start of flash rust everywhere....
 
Good info. It helps all of us to share. I hope not to have to redo mine any time soon but you never know. I do plan on taking the car back apart in the next couple of months because of all the miles I've put on it, around 30K. I have several upgrades planed but more on that as they come to pass.
 
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