My cab leak locations

[NC Tom]

The baby powder trick worked great!!! Now I need to pinpoint the leaks for repair.

 

Driver side had one up under the foam pad behind the pedals. It's likely coming from the firewall, correct?

Also, Driver side had water on the door speaker grill as well as the floor. There is a small gap between the vent and main windows. Maybe leak is there?

Last leak on driver side I think is coming in from the top of the door frame.  don't know if the seal is bad or the door frame is bent or both. Water will come in through there if run through a car wash.

 

The passenger side leak is also firewall, I think. Before the rain came through, I took off the antenna and coated the plastic parts with flex seal. Thinking that and potential leaks from there would be solved.

 

Then there is the back window. Are the seals around the window the only areas water will leak? Is that repaired only with a new gasket?

 

 

[Muncher]

Passanger side good chance that the antenna boot is leaking almost all of mine leaked there i always just seal it with seam sealer 

[87MJTIM]

I am getting water on the passenger side during some rain storms. It appears to come through the heater vent box. I have seen videos on YouTube about leaks coming through the front cowl. The water drips through a metal seam where the sealer has dried and cracked. The videos show cutting an opening in the cowl’s metal to access the sealer seam. Then reapply caulk or RTV to seal the leak. I not sure I would want to use these extremes on my MJ. 

[Pete M]

that's a lot of leaks.  

 

any water that enters the door should drain right out the bottom.  window wipes are never perfect seals.  my guess is that leak is dripping around the door and bottoming out right there so it comes in. 

 

based on what I found in Breanne's truck, I'd suggest pulling the dash and doing it all properly.  it sucks, but is worth it for the access.  rear window likely needs to be pulled and re-glued.  for the cowl, I pulled off the hood and sprayed flex seal through a straw to get it all around. seems to have worked. 

[87MJTIM]

3 hours ago, Pete M said:

for the cowl, I pulled off the hood and sprayed flex seal through a straw to get it all around. seems to have worked. 

How did you do this?

 

These are some of the YT videos I watched.

 

 

 

[Pete M]

the hood hinge hole is your sole access point (without cutting).  I vacuumed through a rubber hose, blew it with compressed air, stuck a tooth brush in and scrubbed around as best I could, repeat.  then sprayed the sealant through a small piece of tubing to get it all over the place.  it wasn't pretty, but there's no way I was cutting an access point for that truck.  this was good enough (and seems to have worked).  there's sheetmetal bits in there that makes this extra fun.

 

 

[NC Tom]

On 9/10/2026 at 7:56 AM, Muncher said:

Passanger side good chance that the antenna boot is leaking almost all of mine leaked there i always just seal it with seam sealer 

I sealed that from the exterior. I guess I need to crawl up under the dash.

[NC Tom]

On 9/10/2026 at 11:09 PM, Pete M said:

the hood hinge hole is your sole access point (without cutting).  I vacuumed through a rubber hose, blew it with compressed air, stuck a tooth brush in and scrubbed around as best I could, repeat.  then sprayed the sealant through a small piece of tubing to get it all over the place.  it wasn't pretty, but there's no way I was cutting an access point for that truck.  this was good enough (and seems to have worked).  there's sheetmetal bits in there that makes this extra fun.

 

 

Oh boy. That sounds fun.

[NC Tom]

On 9/10/2026 at 5:56 PM, Pete M said:

I'd suggest pulling the dash and doing it all properly.

 

Oh no. Not that! Guess I'll check the "How-to" section.

[Pete M]

it's not for the feint of heart, but there's no way to be more thorough with a truck you plan to keep.    there are a bunch of youtube vids too.  plan on replacing things too like the ancient heater core. and various gaskets.  do all you can while in there.  AC complicates life.