Skip to main content ↑ ↓
Topic: Leaking in the rear of coach (Read 1155 times) previous topic - next topic

Leaking in the rear of coach

 Hey everyone,
 I found that my coach has a leak in the back drivers side corner. I see some discoloration below the water catch/gutter (not sure what it is called). I have included pics of what I have found.
 I am completely new to being an RV owner so excuse me if I sound inexperienced-I am.
 My thinking is to hit every nook and cranny with clear gorilla (flex seal) thoughts?
 Also noticed someone had hit the inside corner with some sort of silicone. Seems odd to do on the inside.
1994 U240 3116 Cat 6 speed Allison transmission

Re: Leaking in the rear of coach

Reply #1 –
Before you do a bunch of work and fix something that isn't leaking here are a few thoughts.

Have you actually found water running in or just the stains in the overhead cabinets?

If you just have the carpet stains those could be from condensation from lack of proper air circulation in the coach during the winter time use.  Behind those carpeted panels is an aluminum tunnel that holds the sides and top together.  If not properly vented this area will sweat and even frost up in cold weather causing the condensation stains. These tunnels are not insulated from the outside temps. Sleeping, showering, cooking, and general living all cause a rise in moisture inside the coach. In the summer the A/C takes out the moisture, not so much during the winter  so ventilation or a de-humidifier is the answer.

The drip rail screws may need to be resealed along with the screws on the luggage roof rail mounts.  The clearance lights and and the seam where the rear cap is attached are another spot for leakage.  Both of these if leaking generally won't show up in the upper cabinets.

As far as the " the inside corner with some sort of silicone"  are you sure that they are not using that to hold on a trim piece?

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Leaking in the rear of coach

Reply #2 –
Quote from: Pamela & Mike –
Before you do a bunch of work and fix something that isn't leaking here are a few thoughts.

Have you actually found water running in or just the stains in the overhead cabinets?

If you just have the carpet stains those could be from condensation from lack of proper air circulation in the coach during the winter time use.  Behind those carpeted panels is an aluminum tunnel that holds the sides and top together.  If not properly vented this area will sweat and even frost up in cold weather causing the condensation stains. These tunnels are not insulated from the outside temps. Sleeping, showering, cooking, and general living all cause a rise in moisture inside the coach. In the summer the A/C takes out the moisture, not so much during the winter  so ventilation or a de-humidifier is the answer.

The drip rail screws may need to be resealed along with the screws on the luggage roof rail mounts.  The clearance lights and and the seam where the rear cap is attached are another spot for leakage.  Both of these if leaking generally won't show up in the upper cabinets.

As far as the " the inside corner with some sort of silicone"  are you sure that they are not using that to hold on a trim piece?

Mike
After a rain storm went through it was definitely wet. I wonder what area would cause it to show in the upper cabinets.
 I'm going to just try to seal all that I can I guess.
 I have no idea what the sealant is silicone is there.
1994 U240 3116 Cat 6 speed Allison transmission

Re: Leaking in the rear of coach

Reply #3 –
We had some leakage back in that area. I taped the trim strip between the roof and the rear cap with no residue duct tape, front edge, rear edge and across the top down to the drip rail.  Leak stopped.  So carefully removed the screws and trip strip down as far as it went, cleaned it all up, cleaned the the joint, repositioned the trim strip and put down painter tape about 1/8" from the trim strip on either side.  I removed the trim strip and liberally applied 3M 4000 UV adhesive/sealant to the joint and filled every screw hole.  Then I repositioned the trim strip and screwed it down starting in the center.  It squeezed out sealant on both sides, what you want, and out and around every screw. Then clean up excess sealant, smooth it out along the edges and remove the tape. No more leak.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Leaking in the rear of coach

Reply #4 –
Quote from: Roger & Susan in Home2 –
We had some leakage back in that area. I taped the trim strip between the roof and the rear cap with no residue duct tape, front edge, rear edge and across the top down to the drip rail.  Leak stopped.  So carefully removed the screws and trip strip down as far as it went, cleaned it all up, cleaned the the joint, repositioned the trim strip and put down painter tape about 1/8" from the trim strip on either side.  I removed the trim strip and liberally applied 3M 4000 UV adhesive/sealant to the joint and filled every screw hole.  Then I repositioned the trim strip and screwed it down starting in the center.  It squeezed out sealant on both sides, what you want, and out and around every screw. Then clean up excess sealant, smooth it out along the edges and remove the tape. No more leak.
So you actually removed the strip between the rear and cap,yes?
1994 U240 3116 Cat 6 speed Allison transmission

Re: Leaking in the rear of coach

Reply #5 –
 Yup, Sealant goes underneath, not on top.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Leaking in the rear of coach

Reply #6 –
I found that the rear AC unit causes the roof to sag just enough that the AC sits in a low spot and water seeps in around the seal.

Re: Leaking in the rear of coach

Reply #7 –
Anyone use eternabond tape over the trim to seal?
1995 U320
Build #4677
2011 Honda CRV

Re: Leaking in the rear of coach

Reply #8 –
All the GVs with a flat roof are prone to leaks, ours included. I built a small ramp from blocks about 6 inches tall and run the driver's side up on the it if I'm parked outside. Tilts the coach enough so water does not collect in one spot. Make sure to have both rear tires up on it to avoid overloading one tire.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Leaking in the rear of coach

Reply #9 –
Quote from: Nigel0434 –
Anyone use eternabond tape over the trim to seal?
I have used eternabond tape on a tpo membrane roof and it works as advertised but would be a very last ditch effort to use on my coach. There was no getting it off the tpo, it basically became one compound. I would imagine it's a nightmare to get off fiberglass/gel coat.
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Leaking in the rear of coach

Reply #10 –
Heat gun is the answer to eterna bond removal, I watched a utube video. Set the heat gun little hotter than for decal removal and the mesh comes off. Then again for the residual glue with a broad knife, final cleaning with acetone. I haven't had the pleasure luckily of working on anything other than fiberglass.
88 Grand Villa 36' ORED 3208 (throwaway)Cat.
 Build # 3150
Happiness is the maximum agreement of reality and desire.

Re: Leaking in the rear of coach

Reply #11 –
Quote from: Olde English –
Heat gun is the answer to eterna bond removal, I watched a utube video. Set the heat gun little hotter than for decal removal and the mesh comes off. Then again for the residual glue with a broad knife, final cleaning with acetone. I haven't had the pleasure luckily of working on anything other than fiberglass.
Acetone is pretty hot...just sayin
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)

Re: Leaking in the rear of coach

Reply #12 –
Acetone is what I used to prep all the fiberglass surfaces after running the DA sander. Just a wipe down with a damp cloth. As far as the EB tape, that's what the utube video recommended. It's not real good for open wounds, ouch !
What I've learned about Foretravel roofing is the fiberglass is maybe 1/16" thick and it splits from one side of the coach to the other. Every 4 feet, right where the roof 8 x4 plywood sheets butt together and without a mechanical fasteners it's only a matter of time.
88 Grand Villa 36' ORED 3208 (throwaway)Cat.
 Build # 3150
Happiness is the maximum agreement of reality and desire.

Re: Leaking in the rear of coach

Reply #13 –
Here's a good one for your entertainment, when I started this year on my major roof repairs I began at the front.
When I got to the last 8 feet or so I started into this existing patch, as I started to clean up the leading edge (front) it became evident that a new method had been tried in the north west.
I was in the "land of a thousand screws"
A sheet of 1/16" steel 8' x 1' had been used for the patch, we were leaving for the last trip this year so I cleaned up my mess and lapped it with fiberglass. This will wait till next year before I open Pandora's box thank you very much.
88 Grand Villa 36' ORED 3208 (throwaway)Cat.
 Build # 3150
Happiness is the maximum agreement of reality and desire.

Re: Leaking in the rear of coach

Reply #14 –
And of course they used stainless screws, right? Don't want them to rust and then the leak starts again thru the screw holes when regular steel screws are used.
How do I know? Happened to me when the previous owner had a King Dome satellite dish installed up on the roof of our '89 GV. Screws rotted and I chased leaks for a year until I found that the caulk wasn't even holding the dome in place. and every screw was rotted and even all the screws holding the cables in place.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Leaking in the rear of coach

Reply #15 –
 :-we just went through this ourselves.it was awful ours was the toilet though and we had to do a complete remodel and take all the flooring out the water went from the bathroom to the front it was an awful nasty mess . It's looking better and better everyday