How To FJ40 Leak Under Windshield Frame?

[morf]

I recently purchased a 1976 FJ40. It's a decent restoration, but has a few minor problems. The peskiest problem is water leaking into the footwells behind the dash. I live in Portland, Oregon, so leaks are--well--pesky. The leak is not from the cowl vent or the cowl vent drain. Is also is not from the joint between the cowl and the firewall. And it's not coming from the windshield glass seal. The water comes in only when driving at a reasonable pace, so I figure air pressure differential is a factor. Water appears to seep in all across the front from the steering column to the glove box. It mostly drips to the foot wells, but at highway speeds, a little bit sprays up onto the windshield from behind the dash pad. At this point, my working theory is that it is coming through the gasket that seals the windshield frame to the tub.

First, I'm hoping for critique of my working theory.

Second, I'd appreciate any suggestions on how to fix it. Tomorrow, I plan to fold down the windshield so I can evaluate the gasket. It's a hard top, so I'm not looking forward to that effort. Is it possible to fold the windshield without lifting the entire top assembly? Might I be able to lift the front of the roof high enough by loosening the roof screws and leaving the side panels bolted to the tub?

I'm looking forward to your helpful replies.

 

[60 40]

Theory sounds sound.

You will have to remove most and loosen all of the remaining bolts holding the roof to the tub in order to lift the roof high enough to fold down the window.

 

[morf]

I recently purchased a 1976 FJ40. It's a decent restoration, but has a few minor problems. The peskiest problem is water leaking into the footwells behind the dash. I live in Portland, Oregon, so leaks are--well--pesky. The leak is not from the cowl vent or the cowl vent drain. Is also is not from the joint between the cowl and the firewall. And it's not coming from the windshield glass seal. The water comes in only when driving at a reasonable pace, so I figure air pressure differential is a factor. Water appears to seep in all across the front from the steering column to the glove box. It mostly drips to the foot wells, but at highway speeds, a little bit sprays up onto the windshield from behind the dash pad. At this point, my working theory is that it is coming through the gasket that seals the windshield frame to the tub.

First, I'm hoping for critique of my working theory.

Second, I'd appreciate any suggestions on how to fix it. Tomorrow, I plan to fold down the windshield so I can evaluate the gasket. It's a hard top, so I'm not looking forward to that effort. Is it possible to fold the windshield without lifting the entire top assembly? Might I be able to lift the front of the roof high enough by loosening the roof screws and leaving the side panels bolted to the tub?

I'm looking forward to your helpful replies.

OK, answered my own question about raising the roof. As long as all the screws are in good shape and not rusted into the top, the process is relatively quick. I removed the windscreen frame screws and removed the various hex-head screws that secure the roof to the side panels. You also have to remove the screws that hold the frame part that goes over the passenger and driver door. I did not remove the fasteners that hold the roof to the frame part that goes above the rear doors. I then lift the front of the roof and set blocks between the roof and the side panels. I'll let you know how easy it is to put it back on.

 

[morf]

OK, answered my own question about raising the roof. As long as all the screws are in good shape and not rusted into the top, the process is relatively quick. I removed the windscreen frame screws and removed the various hex-head screws that secure the roof to the side panels. You also have to remove the screws that hold the frame part that goes over the passenger and driver door. I did not remove the fasteners that hold the roof to the frame part that goes above the rear doors. I then lift the front of the roof and set blocks between the roof and the side panels. I'll let you know how easy it is to put it back on.

With the windshield folded, I can see that the cushion (gasket) between the windscreen frame and the cowl is a source of leaks. The OEM cushion does not fit particularly well. It clearly does not seal around the defrost vent holes. I'm going to try to set it with a bunch of sealer, either silicone or RTV. Suggestions appreciated.

 

[Chamba]

Do NOT silicon it in. Silicon causes rust and you'll never get it out. Silicon will also act like a lubricant while it's wet and push the gasket into all kinds of interesting places it shouldn't be.

Buy a new one from City Racer. It'll be in Portland in 2 days. Fix it right and it'll last for another 50 years.

 

[fireflyr]

I have replaced that rubber seal once in the last 23 years. If you are going to the trouble of raising the roof then order a new one. The way mold grows on cars in Portland I wouldn’t half ass it.

 

[brian]

Are you sure that the seal inplace now, is actually an oem part?

 

[samatulich]

Buy a new one.
Worth checking the hood hinges too. Theres a gasket under the hinge plate, buy new ones and rtv the threads on the screws. Easy to do.

 

[pb4ugo]

@Chamba and @samatulich are spot on. Don't glue the seal. The front edge of the cowl seal needs to be oriented just right so it tucks under the lip of the w/s frame and doesnt fold over. The hinge screws can create a leak. You could add sealant to the threads. Water can get between windsheild gasket and the frame too. The outside lip was just as bad as the inside. I used 2x4s to support the top when I folded the w/s down.

 

[morf]

Thanks for the photos and suggestions. The tip to order a new one from City Racer is the most valuable, because City Racer's page for the cushion has loads of photos. Comparing my cushion (which I'm pretty sure is OEM) to the City Racer photos reveals that my cushion is deformed in all sorts of ways. The site also explains that the cushion is supposed to seal where the front of the windshield frame meets the cowl, which makes sense. So I ordered a new one, which I assume is after market, because an OEM one from Cruiser Corps is $450!

 

[Chamba]

It's after market, but very nice quality. He has his stuff made at the same place which makes weather stripping for collector car restorations. Everything I've bought from him thus far fits very well and the rubber feels dense and pliable.

 

[morf]

So the City Racer cushion is fantastic! Thanks for that tip. I think the design with multiple ridges is probably better than OEM. For a little added insurance against Portland leaks, I added a strip of two-side gasket tape to the leading edge. That's probably unnecessary, but it will minimize the potential for water to be pushed under it by the high pressure created by the aerodynamics or our trucks. I was able to drop the windshield by removing most of the screws to the roof and lifting it in the front. I think this was easier than trying to lift the entire top.