Water ingress to trunk

[tony-muscle]

Today i drove in rain. Not by choice but i brought the car for alignment and it took a lot longer than planned so mother nature gifted me with a storm.
In any case, i got home and saw water accumulated in the drop offs. The is not the first time it happened but pretty much when i drive through rain. I saw no wetting along the wheel wells, or from the brake lights or from anywhere. I am suspicious that those silly rubber drains are letting water in. These are no more than 5 years old and they look good but obviously not sealing water in and not letting water out. I am thinking of completely "siliconing" them. Is there any reason for not doing this? Why are they there to start with?

 

[Tnfastbk]

Look for obvious signs of leakage or find someone trusting of you and small enough to fit in the trunk. Shut the lid and spray with a water hose and have them look with a flashlight. That's what I ended up doing. Then purchased this and stopped 99.9% of leakage. Every great now and then of sitting down hill in a storm I will still get a little water. But I know this so I immediately dry it out. Sucks but nature of old flexible cars that we drive. When people say their old car never leaks its because it sits in the garage 99% of the time.

https://www.steelerubber.com/trunk-weatherstrip-20-2863-84

 

[Hemikiller]

Most likely suspect is the rear window. The gutter system drains on the outer portion of the wheel well and will end up in the drop off.

 

[Stanglover]

I found that the water getting into my trunk was totally from the tail lights. My solve might have been a bit drastic, but I get zero water in now. First, I removed the lights and stripped them completely. A good time for a complete cleaning as well. When I reassembled them, I paid attention to how water can get passed the seals. I deduced that water can get passed the aluminum trim around the lenses, so I carefully applied clear RTV behind the trim. Once reassembled, I also added black sealer behind the crappy aftermarket gaskets they sell these days as well as to the taillight panel around the opening. Once they were in, I went the final mile and used black body sealer around the assemblies. Between this and the RTV behind the aluminum trim, I've not had any water getting in. I just dread the time i have to remove the lights, that's going to be a PITA.
Making sure the trunk rubber seal is good is also important. As for the drop off drains, my car still has the originals in. I bought new ones, but never got around to putting them in.

 

[tony-muscle]

I found that the water getting into my trunk was totally from the tail lights. My solve might have been a bit drastic, but I get zero water in now. First, I removed the lights and stripped them completely. A good time for a complete cleaning as well. When I reassembled them, I paid attention to how water can get passed the seals. I deduced that water can get passed the aluminum trim around the lenses, so I carefully applied clear RTV behind the trim. Once reassembled, I also added black sealer behind the crappy aftermarket gaskets they sell these days as well as to the taillight panel around the opening. Once they were in, I went the final mile and used black body sealer around the assemblies. Between this and the RTV behind the aluminum trim, I've not had any water getting in. I just dread the time i have to remove the lights, that's going to be a PITA.
Making sure the trunk rubber seal is good is also important. As for the drop off drains, my car still has the originals in. I bought new ones, but never got around to putting them in.

Definitely not the tail lights. These were recently installed and I don't see any trace of water coming from them.

Most likely suspect is the rear window. The gutter system drains on the outer portion of the wheel well and will end up in the drop off.

I think this is the culprit. I tried last night and I see water leaking over the wheel well, but on the interior side of the wheel well, which eventually drains back to the trunk. This happened only when I poured water between the rear window trim and the body so this may be due to something else besides the gutter system. The water that poured over the window ends up flowing down the outside of the trunk seal.

 

[Stanglover]

Definitely not the tail lights. These were recently installed and I don't see any trace of water coming from them.

Well that's good Tony. Taillights are notorious for leaking and why the panel rots out. Keep your eye on them anyway.

 

[MikeGriese]

The gutter drains in front of the rear wheel opening. It's pretty shallow, so you can get slop over the top of the gutter and into the trunk.

 

[tony-muscle]

The gutter drains in front of the rear wheel opening. It's pretty shallow, so you can get slop over the top of the gutter and into the trunk.

I am kind of confused on this "gutter" system. Will you have some pictures to help me visualize how it works.

 

[MikeGriese]

Here's the gutter on a convertible.




It takes water from the top and directs it into the space occupied by the quarter windows, where it drains out of the car. I'm not certain if there is a similar sized channel in the roofed cars.

 

[Hemikiller]

This is the gutter system for a coupe, you can see the two "spouts" that direct water onto the outer wheelhouse.

 

[tony-muscle]

I need to get inside the trunk to look up into this gutter. Mine is leaking on the inner side of the wheel well towards the trunk so maybe there is a hole or a clog there. I would prefer it to drain by the quarter window space since this will drain forward through the rocker panel, right? Rather than draining into the trunk.

 

[Stanglover]

I need to get inside the trunk to look up into this gutter. Mine is leaking on the inner side of the wheel well towards the trunk so maybe there is a hole or a clog there. I would prefer it to drain by the quarter window space since this will drain forward through the rocker panel, right? Rather than draining into the trunk.

Hmm, that one is new to me, I'll be honest. I suppose I'll have to go digging inside my car now. This doesn't make sense to me on a fastback though.
I learn something new every day!

 

[tony-muscle]

Ok, here is my report after spending a good time in the trunk.

• The water that seeps between the rear window trim and body ends up draining on top of the inner wheel well, which part of it drips down to the trunk and some stay in the area behind the rear seats - probably if too much water drips, some will end up on the rear seat floors.
• The water that seeps between rear window seal and the window drains down on the rear trunk floor near the drop offs, for some reason it drains short of the drop off so some of this water can stay on the trunk floor. This seems to be mainly due to cracking and separation of the seal from the window.
• The water that seeps between the rear window seal and the trim ends up draining outside of the trunk lid seal.

In any case, my problem is that the seal is cracked and there is a unsealed gap between the rear window trim and body. Since I am not planning on removing the rear window (at least for now), I will proceed to use some thinned down seam sealer and brush it in those areas to minimize leakage to the inside of the car.

 

[Stanglover]

Ok, here is my report after spending a good time in the trunk.

• The water that seeps between the rear window trim and body ends up draining on top of the inner wheel well, which part of it drips down to the trunk and some stay in the area behind the rear seats - probably if too much water drips, some will end up on the rear seat floors.
• The water that seeps between rear window seal and the window drains down on the rear trunk floor near the drop offs, for some reason it drains short of the drop off so some of this water can stay on the trunk floor. This seems to be mainly due to cracking and separation of the seal from the window.
• The water that seeps between the rear window seal and the trim ends up draining outside of the trunk lid seal.

In any case, my problem is that the seal is cracked and there is a unsealed gap between the rear window trim and body. Since I am not planning on removing the rear window (at least for now), I will proceed to use some thinned down seam sealer and brush it in those areas to minimize leakage to the inside of the car.

Good to know Tony. You might have to bite the bullet and have a new rubber installed.
When my car was stripped for repainting, I had a new rear window rubber installed. I have not seen the problem you describe but I will take a closer look at that. The only water I saw in the trunk, was clearly due to leakage through or around the light housings.
Although not part of the problem you are having, when the quarter windows were put back in, we made sure that they were adjusted tight against the rubber seal, then that was sealed all around with black body sealer. Quarter windows are bad for leaking and rotting out the floor under the seat.

 

[tony-muscle]

As said many times, once you understand how these cars were designed to handle water it is not surprising to see them rusting. Unbeknownst to the driver, as you go through a rain storm you have waterfalls and rivers inside the car.

 

[Stanglover]

As said many times, once you understand how these cars were designed to handle water it is not surprising to see them rusting. Unbeknownst to the driver, as you go through a rain storm you have waterfalls and rivers inside the car.

............. and Ford didn't give a damn as long as it would last to just past warranty. They weren't call "Rustangs" for nothing.

 

[Cleveland Crush]

Just a quick suggestion and comment:
Use Silicone spray 360 degrees around the rear window gasket on a twice a season schedule. This will do two things; #1. Keep the rubber expanded and water tight. #2 The Silicone will repel water from seeping through the seal via it's surface tension.
Rubber glass seals are replacement items like rubber hoses and tires. They don't last forever.
I still run the original glass rubber on my 1972 and it's 100% leak free (thanks Silicone spray).
Just my thoughts...

 

[Stanglover]

Ah, now I see the light............. or rather the spout.
And yes, I see what you mean Tony, this will drain into the fender drop off, BUT the rubber drain valve is supposed to take care of any water, according to Mr. Ford!! Not one of their brighter ideas for sure.
I posted 2 pics, not sure which one is better. Feeling this "spout" it is without doubt a channel. You can't see that in the pic.

 

[Stanglover]

Just a quick suggestion and comment:
Use Silicone spray 360 degrees around the rear window gasket on a twice a season schedule. This will do two things; #1. Keep the rubber expanded and water tight. #2 The Silicone will repel water from seeping through the seal via it's surface tension.
Rubber glass seals are replacement items like rubber hoses and tires. They don't last forever.
I still run the original glass rubber on my 1972 and it's 100% leak free (thanks Silicone spray).
Just my thoughts...

Amway used to make "Wonder Mist" a silicon spray that was good for just about anything. Great stuff, but like all silicone sprays, keep it off your paintwork.

 

[tony-muscle]

Ah, now I see the light............. or rather the spout.
And yes, I see what you mean Tony, this will drain into the fender drop off, BUT the rubber drain valve is supposed to take care of any water, according to Mr. Ford!! Not one of their brighter ideas for sure.
I posted 2 pics, not sure which one is better. Feeling this "spout" it is without doubt a channel. You can't see that in the pic.

Is that picture taken towards the rear or the front? I don't seem to have that spout. Maybe that's why mine is draining over the interior wheel well.