Rust in rear side windows. (1 Viewer)

[Erwin]

Rust will eventually creep out under the weatherstrip of rear side windows. I took out windows in 2012, sandblasted, epoxy primed and did everything by the book. Still, now in 2024 the rust was back.
So I have repeated the procedure, sandblasting etc..
Window is of the non-sliding type and I reuse the weatherstrip. 1994 HDJ.

Question: any way to avoid rust coming back? On front and rear door window I used bitumen sealant, but according to FSM nothing should be used on side windows. There has never been a leak so not necessary I guess.
The weatherstrip is old and can be stiff. Maybe insert them with silicon grease to soften them up?

 

[SteveH]

10 years is pretty good in your climate for that sort of rust repair. To slow future corrosion, I would grease the seals with silicone grease (against the metal) and wipe off the excess.

 

[jpoole]

Get new seals (OE) at least. There may be other ways to keep that area from holding water but some approaches like adding sealants/adhesives could cause other issues like making future repair harder and may not end up achieving the desired results. I'd do careful research and consideration before altering the stock setup and would be inclined to just put it back as close to "as new" as you can.

Silicone grease, as mentioned above seems like a good/safe option though it may only extend the repair a little beyond a dry install. If you do reuse the old seals silicone can help restore them to some extent though new seals are going to do a much better job of sealing out the moisture.

If you know how to handle it and want to try to make this a "permanent" setup you could use a 3M windshield adhesive or something like 3M 4200 or 5200 to glue the window to the seal and then the seal to the frame but know that this will make removal/cleanup harder and if it's not done correctly may not help with the rust much or at all. The 4200/5200 options may not be a good idea or recommended but I personally have had good results with 5200 between an aluminum framed windows and the surrounding rubber seals. I've not used it between a seal and body though as I wanted to be able to remove the windows again.

The tech involved here is pretty universal so I'm sure you can search more broadly and find an array of ideas from folks restoring and preserving other autos as well. Plenty of cars struggle with this issue and in many cases the water comes in from the top, corners or sides of the seal-body interface but then is held in by the seal on the lower edge which causes the corrosion. Simply cutting drain channels near the two lower edge corners could also help keep this area dry if the water can't be kept out from the upper segments.

 

[Kernal]

I'm not a body repair expert, just learned a few tips along the way, so take this FWIW. Did you use any sort of rust "killing" product before priming/sealing the metal ie: Rust Mort, Rust Kutter, Ospho, or?? Which brand of "epoxy" primer did you use, 1k, 2k, ditto for the top coat??

 

[Erwin]

I'm not a body repair expert, just learned a few tips along the way, so take this FWIW. Did you use any sort of rust "killing" product before priming/sealing the metal ie: Rust Mort, Rust Kutter, Ospho, or?? Which brand of "epoxy" primer did you use, 1k, 2k, ditto for the top coat??

I don't normally use rust killers. Only if I cant sandblast it properly. And I only use 2K products from PPG which should be excellent quality.

 

[Erwin]

Get new seals (OE) at least. There may be other ways to keep that area from holding water but some approaches like adding sealants/adhesives could cause other issues like making future repair harder and may not end up achieving the desired results. I'd do careful research and consideration before altering the stock setup and would be inclined to just put it back as close to "as new" as you can.

Silicone grease, as mentioned above seems like a good/safe option though it may only extend the repair a little beyond a dry install. If you do reuse the old seals silicone can help restore them to some extent though new seals are going to do a much better job of sealing out the moisture.

If you know how to handle it and want to try to make this a "permanent" setup you could use a 3M windshield adhesive or something like 3M 4200 or 5200 to glue the window to the seal and then the seal to the frame but know that this will make removal/cleanup harder and if it's not done correctly may not help with the rust much or at all. The 4200/5200 options may not be a good idea or recommended but I personally have had good results with 5200 between an aluminum framed windows and the surrounding rubber seals. I've not used it between a seal and body though as I wanted to be able to remove the windows again.

The tech involved here is pretty universal so I'm sure you can search more broadly and find an array of ideas from folks restoring and preserving other autos as well. Plenty of cars struggle with this issue and in many cases the water comes in from the top, corners or sides of the seal-body interface but then is held in by the seal on the lower edge which causes the corrosion. Simply cutting drain channels near the two lower edge corners could also help keep this area dry if the water can't be kept out from the upper segments.

I agree that using new seals would be a good idea as they will be softer. That said, I used silicone grease on old seals when I restored my 1974 40 series a few years ago. And they became very soft and had a good fit.
Cutting drain channels is a good idea. I will look into that.

 

[Erwin]

Update. Soaked the weatherstrips in silicone grease, inside and outside. They became very soft and it was a breeze to insert windows. Also, it was not necessary to use soapy water which I dont like, since water will be trapped between steel and seals.