Leak-drivers side-related to under grill catch basin-maybe to plastic square pipe dra

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by phoebeisis, Sep 11, 2012.

  1. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    1998 Suburban-runs great-220,000 miles- last 25,000 and 5.5 years are mine.

    It has had a driver's side front cabin leak-during rain-for 4 years.
    The water comes in "somewhere" behind the emergency brake mechanism-and most of it seems to make its way down that heavy wiring bundle that is behind the driving brake mechanism that is attached to the left side "firewall"-not the firewall between engine bay and carbi-the one to the left- kinda just behind the front wheelwell-just interior to the door.

    I pulled the wipers-pulled grill-got a bit of a look-with mirror-at that big trough under the grill-not a great look- but no OBVIOUS problems.
    I put a hose in the trough-leaks heavily
    Then put hose all the way lateral-literally in the entrance to that 2x1" plastic "drain tube" that drains the drivers side of the trough-draining it several inches down-can't see exactly where it opens- but ends up draining to ground.
    IT LEAKED HEAVILY when in entrance to this drain pipe-hose set to spray wide a bit-so it kinda covered the whel entrance

    I then took the drain tube partially off from the engine bay-looked-didn't see any obvious problem-re-attached it-put hose in
    NO LEAK!! Yeah makes no sense- but a quick check with the hose in the same place-entrance to drain tube- no leak!

    Now ZERO chance-I think-that I fixed anything.
    Help any idea on where it is actually leaking
    How do I fix it?
    I was considering-strongly considering- just blasting undercoating in the trough-hoping to get lucky-figuring some seam had become unsealed over the years-if it had leaked after I checked the tube-I would have-that is what I'm reduced to-gunking EVERYTHING up in the hopes of sealing it.
    I didn't but...
    Now I'm reluctant-very reluctant-to remove parking brake mechanism-not sure how it is attached-and I suspect it might be one of those things that is MUCH easier to remove-that to re-attach. Might be under plenty of tension from the cable-not sure just how much tension you can take off
    In any case-I'm a bit chicken to potentially make it unusable-to fix just a water problem.
    Oh-the finish on these Suburbans-greatest paint in the world-5 years wet- no rust?? Odd but true??
    Not wild about water on wire harness-so better get this fixed??

    Help-leak from drain box-to behind emergency brake-where it is-how to fix seal??

    PS I'm 61 yo-and have "made many things worse" while trying to repair them.Not lately-last 20 years because I've become more cautious-reflective-and internet allows plenty of research before "digging in" in any case I'm aware of learning curve screwups-and my own mechanical limitations
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I know that there is a common issue with that body style truck with the screws that hold the cowl (grill) in place. Water can just run down the screws right into the cab. Most guys just pull the screws out, cover the threads in silicon and put them back in. That seems to stop the leak. Of course yours could always be something else.. I have also seen the joint where the front end meets the cab leak. You can also smear silicon across that in an attempt to stop it.
  3. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    Thanks for the response.
    I silicone sealed the screws-no luck.
    Not sure what you mean-front end meets cab??
    Where is that-relative to the inside of the cab-near door- near firewall on side under the emergency brake?
    I have it narrowed a bit-seems to be getting in-somehow-right under where the emergency brake mechanism is.
    I can get my fingers ABOVE thew emergency mechanism-don't feel "wet" up there-seems to somehow be near the brake

    Of course cab leaks-are a real BEAR to find at times
    Originally I thought it was the weather stripping-I was wrong
    I have it narrowed-for now-to the big drain box-and that emergency brake mechanism-maybe even where the wire bundle come thru??
    PS I "think" I have it narrowed-I've been wrong on this-so if anyone has any other ideas-let me know!!
    Carpet bombing with Eastwood rubberized undercoating shows I have no real good idea!
  4. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    under the cowl you will see a line of stuff that looks like caulk. It us usually painted the color of the truck. When they assemble the truck they put the putty like stuff along the seems in there to stop the leaks. I have seen that crack and leak. But if you have narrowed it down to a lower spot then I would not worry about that. It could be following the wire bundle, it could also be leaking from the top of the windshield, running down the molding and then entering the cab there. Unfortunately you may have to pull the parking brake mechanism and lay under the dash with a flashlight while you have someone spray her down with a hose. Then hopefully you can see where it is coming from
  5. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    If your looking from the inside at the E brake the corner behind the E brake where the corner of the firewall meets the inner cabin panel, and all along the top of the firewall below where the windshield track runs is a seam, this is where the firewall is attached to the body (this seam also runs down lower on the floor board but under the carpet). The fire wall is spot welded to the body and they use a material like plumbers putty to seal the edges of the seam, when the putty gets older it can and will flake away allowing water leaks.
    Like Pikey stated it looks like a bad RTV sealant job, I'm willing to bet if you could get an inspection mirror and some light back along the side behind the parking brake you'll see signs of water leaking through the putty/seam.
    To fix it I would locate it on the outside, behind the fender, and clean it up as much as I can before filling it in with sealant.
    You can slip a long flexible tube over the end of the sealant canisters tip and direct the tube down into where you need to get the sealant.
    I've seen leaks in that general area on some of the trucks and Suburbans I resell, mostly Suburbans so I believe some of the problem is from their flexing during use over the years.
  6. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    TBPLUS 10 Pikey
    I found an area-of that putty sealant-that MIGHT be the leak site.
    It is right out in the open-just in front of and lateral to the edge of the driver's side grill-next to the hood hinge.
    When I gently ran the hose-just there- it leaked-plenty!! So it isn't the trough under the grill-like I thought previously(or it is both-a happy thought).
    I cleaned it up-sprayed it with Eastwood rubberized undercoating-and we'll see. It will be a while before it is hard enough to test.
    Of course it is entirely possible- probably likely-that it is rolling off that-downward-and finding some other old seam to leak through.
    This area is right out in the open-easy to fix-so probably ZERO chance it is THE LEAK.
    Well-maybe I'll get lucky- been on and off chasing this leak for 5 years!!
    After Isaac-I must have had a gallon of water in the padding and carpet-finally had to cut the underpadding out(but it dried quickly-so if the leak is fixed- I'll pI'll put it back down-maybe use a little adhesive-getting ahead of myself
  7. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    With you guys HELP -TBPLUS10 AND PIKEY
    Looks like I lucked out.
    It has rained like heck the last 8 days-NO LEAK!
    The below is what I did-that wide seam of putty sitting right in the open staring me in the face-

    I found an area-of that putty sealant-that MIGHT be the leak site.
    It is right out in the open-just in front of and lateral to the edge of the driver's side grill-next to the hood hinge.
    When I gently ran the hose-just there- it leaked-plenty!! So it isn't the trough under the grill-like I thought previously(must have been getting mist overspray from the hose in trough)

    After 5 years of wet cab- it is fixed(I think hope) I'll post a picture
    Now I have to fix the leak by the barn doors. The doors don't seem to "shut tightly" anymore-the snap shut- but it looks kinda like the doors "bulge out" if you know what I mean-like the hinge is sprung- but it isn't.

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