Water flow through rear quarter window

My car has a large gap between the window of the quarter panel and the panel. This is my first 7173 Mustang, but I am assuming this is the way it was meant to be. The other night I was testing for water leaks. I just finished the floors and want to avoid water on my new floors. Some of you with experience with these cars may already know this, but I was amazed on how much water flows in between the window and the quarter panel into the inside. Literally, a water fall. Basically all the water from the roof on that side flows down the rail and then a lot goes between the window and quarter (see pictures). So that water goes down the inner quarter and eventually exits through a drain hole between the wheel well and rocker on the inside to a hole under the rocker (see rocker picture).

I had a lot of rust in the under-rear-seat area and I was wondering how the water got there. Off course, an obvious option was that the drains get clogged over time and the water on the inner quarter overflows onto the rear floor area. The other not so obvious option :chin:, and this is what happened when I did my leak test, is that as the water drops from the window down into the bottom of the inner quarter it splashes all over, which means that water will land between the inner quarter and the trim. The inner quarter frame has big holes that allow water to splash through. From there the water will flow towards the area under the rear seat and towards the rear floor panel.

That said, I saw leftover goo around the opening in the inner quarter which tells me that these cars probably came with some type of plastic barrier that covers these openings. I assume that most of our cars after so many years don't have these covers. If this cover is there it will stop water from splashing out of the inner quarter. So that's what I did, I glued some plastic film there to avoid this from happening. I could have cover the openings with Dynamat, but I wanted to leave access in the future for inspection.

I am just sharing this experience for you to check and avoid future issues with water. The splashing scenario will probably happen only during a heavy downpour, or while washing the car, but it is possible. Understandably so, I am becoming paranoid about water so even though I am not planing on driving the car when the weather turns rainy you never know when you are caught under a downpour. I want to protect all my hours of work redoing the floor pans. After looking at how the water flows through these cars it does not surprise me how some of them are rust buckets! I am assuming this is the same with all cars of that era. Tolerances were wide back then.

Next step, and maybe some of you can pitch in, is to close or tighten the gap between the rocker panel and window to avoid all this water from going inside the car. Replacing the weather strip may be a good start but I am afraid that the gap towards the rear will still be there.

Here are some pictures explaining the water flow I saw and the last picture showing the plastic I glued to close the inner quarter frame holes.

Note: to clarify, in the picture that shows water flow through the inner quarter, keep in mind that this water flows behind the inner frame.

From what you are describing and just by looking at your pictures, it looks like you need a new roof rail weatherstrip and possibly new window felts. It also looks like the roof rail weatherstrip channel is pulled away from the body in that area. I recommend you pull out the quarter window glass and investigate further. You may end up having to pull out the roof rail weatherstrip channel and clean up that area and maybe put some foam strip between the body and the channel before you put it back in.

From what you are describing and just by looking at your pictures, it looks like you need a new roof rail weatherstrip and possibly new window felts. It also looks like the roof rail weatherstrip channel is pulled away from the body in that area. I recommend you pull out the quarter window glass and investigate further. You may end up having to pull out the roof rail weatherstrip channel and clean up that area and maybe put some foam strip between the body and the channel before you put it back in.

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Can you please help me with pictures so I can see how it looks in other cars? I understand where the felts go, but I am confused in regards to the roof rail weatherstrip. I don't see leakage up by the weatherstrip channel, but rather when it flows between the window and quarter panel.

Sorry man I don't have any pictures right now but if you look at your second picture that shows that there's a hole where the piece of the window felt or a piece of the roof rail weatherstrip used to be. Definitely not supposed to have a hole there and definitely not supposed to have water coming into the car. The new strip of outer window felt/window scraper has a piece that fills that void there. Hope that helps

Sorry man I don't have any pictures right now but if you look at your second picture that shows that there's a hole where the piece of the window felt or a piece of the roof rail weatherstrip used to be. Definitely not supposed to have a hole there and definitely not supposed to have water coming into the car. The new strip of outer window felt/window scraper has a piece that fills that void there. Hope that helps

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Got it... thanks. I saw a picture in the internet of a new felt and I can see the little piece that sticks out that should cover that hole. It may no be 100% leak proof, but it will help. Awesome! Those little things that you don't know that could make a big difference. I can see how this can be happening in a lot of cars without the owner knowing. Water is persistent and will find a way to get inside the car and rust all the metal!

I guess $40 more and another job to add to the list. I will have to disassemble that section later in the year, but for now I want to get the car going.

Cool man, it's actually pretty easy to disassemble all of that area so maybe if you have a nice Saturday afternoon you might be able to tackle it. I have seen many times on fastbacks rot out in that spot behind the quarter window glass. BTW good job on the floor pans

Heres how I addressed this issue obviously applies to a car your going to paint. They all came this way from the factory.

Heres how I addressed this issue obviously applies to a car your going to paint. They all came this way from the factory.

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Awesome.... those gaps in my car really look ugly. The rear window has a gap which creates an area that I am sure will get rusted if left out exposed to the weather. Not planing in repainting the whole car though, so I will have to live with what I have.

If you look at it, those gaps in combination with rotten and cracked weatherstrips cause a lot of issues, which will vary from car to car. Like I said, no wonder why a lot of these cars are rust buckets. And probably not only the Mustangs, but other cars of the era. More motivation to keep the car garaged when there is rain in the forecast. Seriously, I am going to by a car cover and if it starts raining and have the car parked I will cover it. Heck, if I am driving I may as well stop at a rest stop and cover the car :shootself:

Cool man, it's actually pretty easy to disassemble all of that area so maybe if you have a nice Saturday afternoon you might be able to tackle it. I have seen many times on fastbacks rot out in that spot behind the quarter window glass. BTW good job on the floor pans

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Thanks. Those floor pans are my pride. First ever sheetmetal work. Now that I know how hard it is, at least for a novice, I will baby the car more than ever, and keep it hidden from water. I will have to wash it with a barely humid sponge, specially now that has a lot of garage dust and residue.

I will have to wash it with a barely humid sponge, specially now that has a lot of garage dust and residue.

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The best way to wash these cars or any cars for that matter is to do your normal wash routine and heres the key DRY WITH A LEAF BLOWER gets all the water out of the nooks and crannys behind the moldings etc. I've been doing it for years plus if you perfect the finish (polished waxed ) you don't even need soap a quick blast with the hose--leaf blower--detail spray and done.

I have owned one of these since new. I took my 73 Mach 1 back to the dealer several times the rear floor would have an inch of water in it when new. Yes a puddle. They would dry it out and keep trying to chase the leak. It was above the rear window and mine had power windows so all rolled down. The drains in the quarters were filled with sealer also so when they filled up they just ran into the floor. I am sure lots of them were this way.

I would never wash one of these cars with a hose or pressure washer. I just fill a bucket with water and do not use a hose at all. All you are doing is feeding the enemy rust by using a hose. The water pours into the doors, quarters and ponds up in the tail lights. I don't care how good a job you do on all of the restore water gets into the cracks, seams and then spreads like any cancer does.

NEVER WASH ONE OF THESE CARS WITH A HOSE, CAR WASH OR PRESSURE WASHER or you will feed the CANCER.

I have put an air hose inside feeding pressure and put soapy water on the widows and areas suspect of leaks. It will blow bubbles.

Just my experience with these cars even the earlier ones were the same way.

Today's cars go through and e-dip that coats the inside with primer also but they still rust from water in the cracks.

David

Nice vid Qcode!

Wish i had seen it a year ago could have saved hours of SMAO.

Paul

well my solution is inelegant and will draw the ire of purists, but I seal that area with 3m 5200 marine sealant. Tape off on either side put a bead down and smooth it. Be aware that this stuff takes a week or more to completely cure.

The rear window is another source of leaks as well. It might be worth buying a seal and having a window man put it in for you-I figure I could do it myself, but that trim is too easy to damage to risk it.

I have owned one of these since new. I took my 73 Mach 1 back to the dealer several times the rear floor would have an inch of water in it when new. Yes a puddle. They would dry it out and keep trying to chase the leak. It was above the rear window and mine had power windows so all rolled down. The drains in the quarters were filled with sealer also so when they filled up they just ran into the floor. I am sure lots of them were this way.

I would never wash one of these cars with a hose or pressure washer. I just fill a bucket with water and do not use a hose at all. All you are doing is feeding the enemy rust by using a hose. The water pours into the doors, quarters and ponds up in the tail lights. I don't care how good a job you do on all of the restore water gets into the cracks, seams and then spreads like any cancer does.

NEVER WASH ONE OF THESE CARS WITH A HOSE, CAR WASH OR PRESSURE WASHER or you will feed the CANCER.

I have put an air hose inside feeding pressure and put soapy water on the widows and areas suspect of leaks. It will blow bubbles.

Just my experience with these cars even the earlier ones were the same way.

Today's cars go through and e-dip that coats the inside with primer also but they still rust from water in the cracks.

David

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I'm with David. I don't have to drive the car in the rain so I ty and make sure I don't. And, I no longer take a hose to it. I have found water in the passenger side trunk well which one day I will track down the source but for now the car does not see water.