What I learned about my leaking windows

[Oldyeller]

I have a 2004 IC CE200 that I'm converting. During the tear out I discovered that my windows leak quite nicely thank you very much. I've been contemplating how I might address this problem but didn't really understand exactly how they were leaking.

I took out about 8 feet behind the rear axle and now I'm in the process of reattaching the end cap. Today I got to the point of needing some sheet metal for the reattachment and, of course, harvested it from the section I took out. You can see in the picture below how the section I pulled out hit the ground and how it was sitting today. I started by cutting out a section of floor crossmember and then a couple sections of side wall.

After that I wanted to setup a couple cuts from the roof but wanted to use the end of the roof that was on the bottom. I couldn't move it alone so I cut the 4 ribs and the roof fell away and then pushed the floor over.

I decided to take a closer look at where the ribs go into the side wall making up the ends of the window frames. I've included some pictures in the next posts showing what I found.

I don't know if this might be helpful to anyone other than someone else that might have an IC CE model but figured it couldn't hurt to share it.

[Oldyeller]

In the first picture I peeled the thick layer of sealant out of the corner of the window frame. I'm sure this was put in at the factory. It was still pliable but I'm sure, in many places, it was leaking. You can see that it peeled away cleanly making me wonder how well it was sealing.

The second picture is from the inside showing the same corner. There is a seam between the sill and outer skin.

In the third picture you can see that the sill doesn't go all the way to the rib and it isn't welded.

[Oldyeller]

As you can see from the first picture the sill isn't welded or bonded to the rib fixture, it's just sitting on top of it depending on the sealant to keep the water out. I'm sure in some cases it held but I'm just as sure in others it had failed because I watched water dripping off the interior wall during a rain shower.

The last picture gives a better view of the seam.

Short of welding every one of those seams I have no idea how to stop the leaking with certainty. Maybe this is my chance to learn how to TIG weld?

[ACamper]

That is where my windows were leaking from.

I cleaned the old sealant/caulking out and put new caulking in. Good caulking will last years, wielding might be a bit of overkill. All you need to do is keep water out. I used a 5-1 putty knife to clean the old stuff out and about 3 tubes of new caulking. It was about $15-$20 and 4-5 hours of labor. Haven't had any leaks.


Thanks for the good pics. They should help someone in the future.

[musigenesis]

Just got your voicemail - sorry, didn't recognize your number earlier. Too late to call now? I'm a 5 am to midnight type myself.

Regarding the window leaking: I'll happily be corrected on this, but I don't think the bus manufacturers use any sealant on the windows at the factory. They rely on the window units themselves being watertight, at least the bottom half (and they aren't always), and on the tight fit of the windows into the openings in the body walls. I think this works well enough in the early years of a bus' life, but the working and vibration eventually opens things up and allows water in. Bus garages - if they notice this leakage at all - then glop the windows up with something or other, and that's the stuff we end up seeing in our buses. My bus had the remains of at least three different attempts to seal up the windows all over it. I want to sneer at their feeble attempts, but I haven't stopped the damn leaks yet either.

The gap that you're describing around the corner of the openings is just inevitable given the construction method. The c-channel sort of beam that forms the ledge the windows rest on has notches cut in to fit around the ribs and then they're crudely spot-welded to each rib. In order to make those corners watertight (without sealant) they'd need to weld to them up completely (like you're suggesting) but even then the water coming through or around the windows would just go somewhere else inside (and it would make the bus construction slower and more expensive).

[ACamper]

On my bus what makes me think the sealant on the bottom of the windows was from the factory is, the sealant was all uniform down the entire bus. It seemed to be applied at the same time down every window base. There is a lot of it in every corner deep inside the corner that give me the impression they they put the sealant down then installed the window.

I have only tore into my bus so my experience is just that one bus.

In this video they show the window frame at 2:37

https://www.youtube.com/watch?v=-Wx11hn7d58

you can see the fold(and gap) on the bottom corner of the frame. That's how my window frames are, at the inside bottom corner there is a gap. That's where my leaks were coming from. Water would pool on the window ledge then drain into the corner.

Thinking about the window frame also made me wounder if the gaps could allow for flex. Which makes me wonder if wielding them might possible remove flex relief points.

[Native]

I just love those "how a school bus is made" videos! Thank you for posting it.

[Oldyeller]

Originally Posted by ACamper

On my bus what makes me think the sealant on the bottom of the windows was from the factory is, the sealant was all uniform down the entire bus. It seemed to be applied at the same time down every window base. There is a lot of it in every corner deep inside the corner that give me the impression they they put the sealant down then installed the window.

I have only tore into my bus so my experience is just that one bus.

In this video they show the window frame at 2:37

you can see the fold(and gap) on the bottom corner of the frame. That's how my window frames are, at the inside bottom corner there is a gap. That's where my leaks were coming from. Water would pool on the window ledge then drain into the corner.

Thinking about the window frame also made me wounder if the gaps could allow for flex. Which makes me wonder if wielding them might possible remove flex relief points.

I wonder if 3M panel bond would hold on those small overlapped joints. Be easier than welding and in my situation since I'm going to, eventually, remove those inner panels I could very easily put a clamp on the overlapped joint.

[indigo_k]

Curious what y'all think about using aluminum tape as a sealant in cases like this:

I've used it to seal up a couple smallish holes (3/8" or so) and it seems to hold up just fine against rain. Would be easier to manage than full-on welding, and would probably last longer than caulking/sealant.

Or is this just wishful thinking?

[HamSkoolie]

It will probably "work" but it's awfully thin. We are using a combination of rivets and plastic plugs to seal the holes in our steel floor pan. We have quite a few 1/8" holes where the original plywood flooring was secured to the steel and then all the seat bolt holes.
The small screw holes are just the right size for a 1/8" zinc coated steel rivet with a very short (1/16") grip. The seat bolt holes were (I think) a 3/8" diameter and will be filled with plugs.
We will apply a dab of polyurethane sealant to each rivet and plug before installation.
Much heavier duty than the aluminum tape but still no welding.