Sealing Firewall leaks

[Akula69]

I have been slowly working towards locating all the pesky leaks that the MJ has (after replacing a great amount of the floor pan). Unfortunately, after it rains I still get a small amount of water in the truck, and I have no intention of putting down new carpeting until I handle the problem.

 

I have not yet replaced the cowl to hood seal, but suspect that the leaks are around the penetrations through the firewall. Althought I have an extra seal I do not believe that will completely solve the problem. Unfortunately, many of the firewall penetrations are covered with grommets and/or seals that are made onto the cable (or whatnot) that passes thru the hole, and most are no longer available (like the speedo/cruise control cable which comes with the non-removable grommet made onto the cable).

 

My question is: Has anyone tried to seal around these penetrations in the firewall and, what have you tried?

 

I tried some black silicone around the speedo cable, which worked for a short while but then the movement of the cable broke it free. (however, I used the same silicone around the hole I made for the engine bay harness CPS bypass mod, and so far it has held).

 

Any other ideas?

 

Thanks.

[maddzz1]

I would try some of the expandable insulation foam stuff. The only problem is alot of them retain water.

[garmj]

When I did my rust repair I gutted the entire cab wiring,dash,A/C case insulation and everything else. I did all repairs then applied spray on bedliner and undercoating. When I reinstalled everything I ran a bead of RVT silicone around all the holes and on each component and let it set up overnight, then I reinstalled everything. NO LEAKS :bowdown: Good Luck

[garmj]

I had a van once that someone filled all the areas behind the inside panels with that expandable foam and it literally caused the outside metal to rust completely away from the inside (in Florida). If you plan on keeping your truck I wouldnt do that. :no:

[summerinmaine]

Move to the desert. Problem solved. :rotf:

[Akula69]

Move to the desert. Problem solved. :rotf:

 

Ah. Wonder why I didn't think about that! :D :hmm:

[SuperWade2]

Subscribing.... I have my carpet sitting on a sawhorse in my garage...had 2" of standing water on the floor of my cab and am still looking for how it got there...

[summerinmaine]

Subscribing.... I have my carpet sitting on a sawhorse in my garage...had 2" of standing water on the floor of my cab and am still looking for how it got there...

 

 

Even though I'm in the desert, I've pretty much pulled all the carpet out of my truck.

 

Why should a work truck have carpeting in the first place?

 

I'll probably fit some rubber mats, but only for sound/heat insulation.

[jbhill]

please please PLEASE go to an autobody supply store and get some seam sealer. silicone will NOT fix water leaks in seams. don't expect to paint over it either. silicone will eventually fall out.

 

i use this stuff at work alot, it is REALLY reasonable i think its 15 bux a tube

 

[garmj]

please please PLEASE go to an autobody supply store and get some seam sealer. silicone will NOT fix water leaks in seams. don't expect to paint over it either. silicone will eventually fall out.

 

i use this stuff at work alot, it is REALLY reasonable i think its 15 bux a tube

 

This aint my first rodeo. What I was reffering to was the holes where the wiring,cables and hoses go thru. I totally agree that seam sealer is a great fix for body seam leaks but where my orignal problem came from was leaks around the fuse block and the a/c case. Seam seal won't work there.

[SuperWade2]

Is there "gasket" type material on the bracket thing where the steering column comes through the firewall... it appears, at least on the driver side water dripping from there, any maybe behind the fuse box... still need to check the cowls...

[mjeff87]

regarding the expandable foam products mentioned, there are two types.....open cell and closed cell. It's the open cell stuff that you should avoid for automotive applications, that's the one that captures moisture.

 

Jeff

[SuperWade2]

I put the hose on the hood on my inclined driveway... water is coming in pretty much through every place where there is something coming through the firewall... weeeeee.....

[Pete M]

Sounds like it's time to replace that rear hood gasket. Or do as I did and squirt a bit of silicone in the gasket to prop it up some. :thumbsup:

[SuperWade2]

Sounds like it's time to replace that rear hood gasket. Or do as I did and squirt a bit of silicone in the gasket to prop it up some. :thumbsup:

 

Suppose that's something nobody "sells" new any more???

 

SW2

[flint54]

The rear hood gasket is part number 55235178AB and is available from: http://www.chryslerpartsdirect.com/ for $23.01.

[jbhill]

you could remove the grommet and use buyteyle(sp) tape(dumdum) in its place.

[mfpdm]

The rear hood gasket is part number 55235178AB and is available from: http://www.chryslerpartsdirect.com/ for $23.01.

 

I'm assuming that since it list all the years that this would be the newer style gasket which is much better than the older one. :thumbsup:

 

:cheers:

[SuperWade2]

The rear hood gasket is part number 55235178AB and is available from: http://www.chryslerpartsdirect.com/ for $23.01.

 

This thing?

 

[Codycobra84]

Subscribing.... I have my carpet sitting on a sawhorse in my garage...had 2" of standing water on the floor of my cab and am still looking for how it got there...

 

Ditto on everything

 

-Cody

[Akula69]

The rear hood gasket is part number 55235178AB and is available from: http://www.chryslerpartsdirect.com/ for $23.01.

 

This thing?

 

 

SW2 - the image is what mine looks like...it has these little plastic push pins to hold it in place. I managed to recover a used one in pretty good shape from an '89...but it may be too compressed (from use) to be effective in sealing.

 

I'll know more when I strip the cab for re-painting because it'll give me the chance to seal around all the holes. I like the seam sealer idea, but believe it sets up too hard for items like the speedo and shift cable (both of which move in thier grommet under use). Perhaps a combination of a new cowl seal and some sort of sealer is the answer.

 

Another thought would be some sort of diverter welded to the firewall above each grommet (assuming there is not too much water coming up from below but only running down the firewall). Of course that would require a lot more work.

[garmj]

I havent even reinstalled the hood to cowl seal And I have 0 leaks. Sealing the holes where all the wiring ,hoses ,steering column is more important that seal won't do you any good if you run thru a deep puddle.BTW I pressure washed the engine compartment after I sealed it still no leaks.

[SuperWade2]

What should I be looking for If I pull the Cowl Cover thing under the wipers off? Is there a "drain" or something that can get clogged causing problems?

 

Wade

[Pete M]

If you pour water into the cowl, you should see it come out below, behind the fender.

I would be looking inside the cowl for cracks or rust holes.

[SuperWade2]

If you pour water into the cowl, you should see it come out below, behind the fender.

I would be looking inside the cowl for cracks or rust holes.

 

Looks REALLY clean inside...no rust, not much dirt or muck at all...

 

I already put it all back together but will dump some water one... already ordered a new Cowl Seal and used some RTV silicone inside where I think the water was coming in...

 

Sw2