[Alex Tugbang]

I have a 1969 mustang grande and recently when I went to wash it there was a hell of a lot of water in the trunk around the gas tank on the drivers side. I thought it was the trunk weather seal and replaced it but it did not help at all. Like there was a large puddle on that whole side starting back near the tail lights then another puddle back down in the gas tank indentation/rear seat area. I do not see any water dripping from the rear window area or up near the rear package tray. I am thinking it may be the tail lights or the quarter panel extension weather seal - but I do not see exactly where it was dripping from.

Later today I am planning on climbing into the trunk with a flashlight and having someone pour water over it to see if my assumption is correct. But please let me know your thoughts and ideas!

 

[Rufus68]

What is the source of water, sitting in rain or driving in rain? If you've been driving in rain, then the possibilities of water entry would include underneath.

 

[Blues Power]

leaks can be hard to find as water can travel from elsewhere before it drips

youre on the right track. pin point it with the light

but to me if its leaking that bad sounds like the trunk seal. they have to be put on perfect and the truck latch has to grab it tight

 

[4ocious]

The first test (and an easy one) I would do is place a flashlight or two in the trunk and close the lid in a completely dark garage. See any light coming out anywhere?

 

[Alex Tugbang]

What is the source of water, sitting in rain or driving in rain? If you've been driving in rain, then the possibilities of water entry would include underneath.

I found this while the car was parked and I was lightly spraying it with the hose in the rear - rinsing it before watching it. There are no holes in the trunk for water to come in underneath and when I had the gas tank installed I put a foam seal in around it to make sure of this. I still have yet to drive it in the rain though.

 

[Alex Tugbang]

leaks can be hard to find as water can travel from elsewhere before it drips

youre on the right track. pin point it with the light

but to me if its leaking that bad sounds like the trunk seal. they have to be put on perfect and the truck latch has to grab it tight

Ill try pinpointing it tonight then thank you. When I installed the trunk seal I ran a hose specifically around the trunk seal to make sure it was not the problem and was not leaking from there anymore

 

[Alex Tugbang]

The first test (and an easy one) I would do is place a flashlight or two in the trunk and close the lid in a completely dark garage. See any light coming out anywhere?

Good idea ill try that and if I don't see anything Ill try the pouring water while I'm in the trunk

 

[Alex Tugbang]

How hard is it to replace the quarter panel extension weather seal?

 

[RCL23]

Put a very bright light in the trunk at night in the garage with all the lights off and close the trunk. See where light is leaking out. This worked for me.

 

[awhtx]

Do you have the foam seals on the taillights that seals them to the taillight panel?

 

[Alex Tugbang]

Do you have the foam seals on the taillights that seals them to the taillight panel?

Im not sure I have not checked. I was actually planning on redoing all the tail light seals within the next week as I was going to upgrade to Sequential Led's and the kit I am getting comes with all new seals for it. (Here is the kit I am planning on getting from CJ Pony https://www.cjponyparts.com/sequential-led-taillight-kit-1969/p/TLK23/ )

 

[BW66]

Check your back window and area around it

 

[Alex Tugbang]

Check your back window and area around it

Should I try and pour water around it? How hard would it be to replace that seal if it turns out to be that one?

 

[BW66]

They can be a pain. I don't like it and be careful removing the back glass trim.

 

[JSHarvey]

I have a 1969 mustang grande and recently when I went to wash it there was a hell of a lot of water in the trunk around the gas tank on the drivers side. I thought it was the trunk weather seal and replaced it but it did not help at all. Like there was a large puddle on that whole side starting back near the tail lights then another puddle back down in the gas tank indentation/rear seat area. I do not see any water dripping from the rear window area or up near the rear package tray. I am thinking it may be the tail lights or the quarter panel extension weather seal - but I do not see exactly where it was dripping from.

Later today I am planning on climbing into the trunk with a flashlight and having someone pour water over it to see if my assumption is correct. But please let me know your thoughts and ideas!

Make sure the person helping you (if you get in the trunk) is not a practical joker type!

 

[Alex Tugbang]

Well I tested it and turned out to be the tail lights AND rust underneath the rear windshield moulding. I covered the rust in the holes with some silicone because why not and the new LEDs also came with all new gaskets. Went to install the new tail lights and this happened... (Excuse the stickers for the rear). I guess the best option will be to bondo it up until I start body work and just get a whole new tail light panel...

 

[bossboys]

time I would get some rubber membrane and some seam sealer and seal it up as best as you can to keep the water out

 

[JSHarvey]

Looks like there was a lot of body filler there already. Getting a new panel, as you mention, is the way to go. In the short term just cover it up like you said. Sad to find such a mess, but it is fixable.

 

[Alex Tugbang]

UPDATE:

Filled in the rust with fiberglass and bonds with the help of a friend. Letting it dry with primer over it and waiting for new tail light body hardware to install. Filled the holes around the rear window with silicone and am waiting to put the new tail lights in to see how it all holds up.

Just makes me think that when I actually do start to do body work I am going to have ALOT of problems with rust and filler.

 

[bossboys]

UPDATE:

Filled in the rust with fiberglass and bonds with the help of a friend. Letting it dry with primer over it and waiting for new tail light body hardware to install. Filled the holes around the rear window with silicone and am waiting to put the new tail lights in to see how it all holds up.

Just makes me think that when I actually do start to do body work I am going to have ALOT of problems with rust and filler.

Thats my suggestion if your driving it and putting off repairs for the future. Good thing they have so many parts for these cars?