240 Rust / Water issue. Rockers and Floor

[bluebandit2g]

Pulled the carpet recently to troubleshoot a ABS issue. Noticed some water around the rockers. Rust also but just right in the crevice where the floor meets the rocker area From the passenger kick panel back to the rear cabin floor. Is this from leaves etc blocking the channel under the rocker and not allowing water to drain quickly ? What do you folks do for this ? Dry it out, treat the rust then put some seam sealer in that groove ? Shop Vac/Blow out the channel behind there of leaves and debris ?

 

[2manyturbos]

More likely the windshield is leaking.

 

[240 240]

have you cleared out the cowl drains? use an air compressor or a long plastic rod to clear out from underneath.

 

[bluebandit2g]

Ill spray some water on it and watch it while i have the carpet pulled back.

have you cleared out the cowl drains? use an air compressor or a long plastic rod to clear out from underneath.

For sure some debris in there. I pulled the plastic plug from near the kick panel in the rocker area. Letting it dry a bit then ill take some compressed air and vacuum and see if i can clear them out. Is there a drain line or anything in there or just the cowl area drops down to the body/fender. No sunroof on the car so no drain for that.

 

[bluebandit2g]

spent a couple hours cleaning the passenger side cowl and drain side, cleaned a ton of crap out of the rockers. Poured some water directly down that side of the cowl. Water is for sure coming in at the seam where the rocker meets the floor. I can scrape out and treat the rust with some Oxphor then seam seal that. There is also one small trail of water coming from the firewall somewhere. It is directly in line with the wiper motor but i can't see where its coming in because its behind the computers and insulation. Im wondering if the grommet on the wiper motor has deteriorated ?? Anyone seen that be an issue. Photos attached. Areas circled where water runs in.

 

[Jack]

Wiper motors, windshields leak there

You need to check

 

[Jack]

Remove the glovebox for full frontal view

 

[2manyturbos]

spent a couple hours cleaning the passenger side cowl and drain side, cleaned a ton of crap out of the rockers. Poured some water directly down that side of the cowl. Water is for sure coming in at the seam where the rocker meets the floor. I can scrape out and treat the rust with some Oxphor then seam seal that. There is also one small trail of water coming from the firewall somewhere. It is directly in line with the wiper motor but i can't see where its coming in because its behind the computers and insulation. Im wondering if the grommet on the wiper motor has deteriorated ?? Anyone seen that be an issue. Photos attached. Areas circled where water runs in.

That is a very common leak source.

 

[945T]

A firewall leak at the wiper motor assembly with water in the passenger side footwell isn't uncommon in 240s. It could be existing putty sealant that's dried or cracked, but more likely it's a bad motor shaft grommet. Butyl ribbon caulk (sold in grey or black rolls in building supply weatherstrip sections) can be used to seal firewall leaks, but a bad grommet is a bit more complicated to deal with. Refer to Art's comprehensive article on 240 wiper motors here https://cleanflametrap.com/wiper.html About 3/4 of the way down in the article is the section on the wiper motor grommet.

For driver side water leaks, a common issue is rust behind the windshield rubber gasket (look for rust stains in the surrounding paint) or the seal failing at the corners of the windshield, especially the driver side lower corner and water getting down around the fuse panel. I've always figured that grit getting caught behind the rubber gasket can eventually scratch through the paint and allow rust to start. If the windshield has ever been replaced then it can also be tricky for the glass techs to get it properly centered so the curvature at the corners matches the curvature of the window frame. As the rubber dries and deteriorates with age the seal can open up years after installation.

The source of a windshield leak can be difficult to spot up under the dash. Leaks can be isolated by putting duct tape over sections of the window frame and squirting it with a hose while you watch for water dripping down anywhere under the dash. Start by taping the entire frame then exposing the lower corners and work your way across then up until a leak starts.

 

[j.pelchat]

And what can be done if the source of the leak is found?

 

[Crustacean Wagon]

I put a new wiper grommet on mine and then sealed the whole windshield with lexel caulk, my favorite clear silicone. That was last June, as my toes would get dripped on when it rained. Wasn't ready to pull the windshield to fix metal, as my car will get a full paint at some point, and that will be when I pull the glass. I was (and am) prepared to keep caulking it until then. So far 13 months and ~25k miles as a daily and no leaks. It's ugly as hell but the car is already like 5 colors, so don't care

 

[petiww]

Also the sealant at the firewall edges can leak. This is right underneath the cowl area, where the floor pan, inner A pillar and bottom of cowl sheets join. On the left side the hood cable opening is very near.
I suggest flushing from the cowl grid to the sides to clean this area from above.
I also suggest to clean the area behind the suspension towers.

 

[240 240]

That is a very common leak source.

for cars not in California
OP crush your car.