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Home » Public Forums » GMCnet » Rear Wheel Well shell seals (How do you seal the Wheel well shell to the floor?)
Rear Wheel Well shell seals [message #349322] Wed, 16 October 2019 10:58 Go to next message
GatsbysCruise is currently offline  GatsbysCruise   United States
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Registered: January 2017
Location: Waukegan, Illinois
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Senior Member
The REAR wheel well shells are not ideal in the way they seal from what I see.
I am ok with plastic, it won't rust but it should have gone down in front of the wood plys, protecting it from splash. Instead the plastic wheel well shell rests on top of the ply and some kind of goop is plastered over the ply.
- So my situation is, that goop has aged and cracked, fallen off in some places.
I have voids exposed and big concerns to protect the wood plys.

- anything with stickum, like waterproof tape with super stickum, does not want to stick to the plastic wheel well, at least not very well.
AND THE VOIDS, there are some spaces that were just gooped up.

- In my search to seal this up, I was wondering if filling the voids with expanding foam then covering with liquid rubber, like that stuff "as you've seen on TV", where they cut the bottom of a boat out and put in a screen then paint this liquid rubber and go screaming across the lake. would this work?

- My ideal plan would be to fill in all those voids and cover all the way down, over the ply so water would be most likely to just run off the sealant.

- The goop that I am finding is like a rubber compound that has hardened and cracked. I am guessing it is OEM as I have not seen a lot of upgrades from the 3 POs that owned the GMC before me.

- How about filling the voids with expanding foam, and coating with truck bed liner? The foam is firm enough after curing, the truck bedliner cures firm and pretty strong.

- Have any of you tackled this concern and is there a permanent repair and what did you use to seal over the ply? Did you fill the voids?

As always, many thanks for any information that you share.


GatsbysCruise. \ 74GMC260 Former Glacier Model style. \ Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO - UBUNTU VOYAGER - Berzin Auto Center

[Updated on: Wed, 16 October 2019 11:04]

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Re: [GMCnet] Rear Wheel Well shell seals [message #349323 is a reply to message #349322] Wed, 16 October 2019 11:09 Go to previous messageGo to next message
Emery Stora is currently offline  Emery Stora   United States
Messages: 959
Registered: January 2011
Karma: 4
Senior Member
If you look into the wheel wells behind the bogie arms you will see the edge of the plywood floor. There is a seam there that sometimes has a leak. When driving in wet weather the tires will throw water into that crack and it will run onto the top of the floor and your carpet will get wet.

Use a polyurethane caulk where the plywood floor meets the bottom of the wheel well liners with some black polyurethane sealant.. If you look closely just above the plywood you will probably see a little crack. Seal the front , the wall opposite the tires and the back of the liner and it will likely fix the problem. You can even coat the edge of the plywood.

I used Loctite PL sealant that I bought at Home Depot. It comes in black and other colors. One tube says t is made for foundation or roof and flashing sealing and also a tube that says "Windows and Doors" and another tube that says concrete. They are the same thing except for the color even though they have different labels. This comes in a standard caulking gun tube. Loctite has now bought out PL so look for the Loctite PL. It comes in Door and Window (white) , Concrete (Grey) and Roof and Flashing (Black).
The black will look best in the wheel well.

I have had to do this a couple of times, a few years apart, as the seam reopened after a few years .

That same black sealant works well around windows and for roof leaks and it is paintable. If using it on a roof seam use masking tape on both sides of the seam, fill the seam and smooth it with your finger and pull off the masking tape while it is still uncured.
After a week or so you can spray some white (or ivory) colored paint on it. Acrylic spray can works well. The Krylon Antique white matches many of the GMC beige colors.

Emery Stora
77 Kingsley
Frederick, CO

> On Oct 16, 2019, at 9:58 AM, slc via Gmclist wrote:
>
> The wheel well shells are not ideal in the way they seal from what I see.
> I am ok with plastic, it won't rust but it should have gone down in front of the wood plys, protecting it from splash. Instead the plastic wheel well
> shell rests on top of the ply and some kind of goop is plastered over the ply.
> - So my situation is, that goop has aged and cracked, fallen off in some places.
> I have voids exposed and big concerns to protect the wood plys.
>
> - anything with stickup, like waterproof tape with super stickum, does not want to stick to the plastic wheel well, at least not very well.
> AND THE VOIDS, there are some spaces that were just gooped up.
>
> - In my search to seal this up, I was wondering if filling the voids with expanding foam then covering with liquid rubber, like that stuff "as you've
> seen on TV", where they cut the bottom of a boat out and put in a screen then paint this liquid rubber and go screaming across the lake. would this
> work?
>
> - My ideal plan would be to fill in all those voids and cover all the way down, over the ply so water would be most likely to just run off the
> sealant.
>
> - The goop that I am finding is like a rubber compound that has hardened and cracked. I am guessing it is OEM as I have not seen a lot of upgrades
> from the 3 POs that owned the GMC before me.
>
> - Have any of you tackled this concern and is there a permanent repair and what did you use to seal over the ply? Did you fill the voids?
>
> As always, many thanks for any information that you share.
> --
> GatsbysCruise. \
> 74GMC260 Former Glacier Model style. \
> Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
> UBUNTU VOYAGER - Berzin Auto Center
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org


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Re: [GMCnet] Rear Wheel Well shell seals [message #349324 is a reply to message #349322] Wed, 16 October 2019 11:23 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
Messages: 6806
Registered: May 2010
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What i have used is pretty extreme. I agree that the wheel wells on the GMC
are an afterthought. The edge grain on that plywood is not happy exposed to
the splash of road spray. Even if you gut the coach to gain access to the
wheel wells, they still sit on top of the floor, leaving the edge grain
exposed. Not the best, nearly the worst way it could have been done.
So, what I have done to coaches when the bogies were removed, was to
make a flashing that extends from mid way down the wheel wells to overhang
that edge grain. Rustoleum makes a comparable rubber like spray coating to
the floating screen door stuff. And it really gets on everything. Glove up.
I pressure wash the wheel wells, spray the wheel wells and the flashing
with the spray coating, and using plastic pop rivets ( yes, I said plastic)
attach the flashing to the wheel wells. When the coating has cured, I top
spray everything in the area. Mask off areas you don't want that stuff,
it's a bi#$@ to clean up. Wheel spray throws upwards, too. So make sure
your wheel wells are sealed above, too. Lots of time invested here.
Jim Hupy
Salem, Oregon

On Wed, Oct 16, 2019, 8:59 AM slc via Gmclist
wrote:

> The wheel well shells are not ideal in the way they seal from what I see.
> I am ok with plastic, it won't rust but it should have gone down in front
> of the wood plys, protecting it from splash. Instead the plastic wheel well
> shell rests on top of the ply and some kind of goop is plastered over the
> ply.
> - So my situation is, that goop has aged and cracked, fallen off in some
> places.
> I have voids exposed and big concerns to protect the wood plys.
>
> - anything with stickup, like waterproof tape with super stickum, does not
> want to stick to the plastic wheel well, at least not very well.
> AND THE VOIDS, there are some spaces that were just gooped up.
>
> - In my search to seal this up, I was wondering if filling the voids with
> expanding foam then covering with liquid rubber, like that stuff "as you've
> seen on TV", where they cut the bottom of a boat out and put in a screen
> then paint this liquid rubber and go screaming across the lake. would this
> work?
>
> - My ideal plan would be to fill in all those voids and cover all the way
> down, over the ply so water would be most likely to just run off the
> sealant.
>
> - The goop that I am finding is like a rubber compound that has hardened
> and cracked. I am guessing it is OEM as I have not seen a lot of upgrades
> from the 3 POs that owned the GMC before me.
>
> - Have any of you tackled this concern and is there a permanent repair and
> what did you use to seal over the ply? Did you fill the voids?
>
> As always, many thanks for any information that you share.
> --
> GatsbysCruise. \
> 74GMC260 Former Glacier Model style. \
> Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS
> FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
> UBUNTU VOYAGER - Berzin Auto Center
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Re: [GMCnet] Rear Wheel Well shell seals [message #349325 is a reply to message #349323] Wed, 16 October 2019 11:43 Go to previous messageGo to next message
Jp Benson is currently offline  Jp Benson   United States
Messages: 649
Registered: October 2011
Location: Fla
Karma: 2
Senior Member
I cleaned up the outside of the wheel wells and sprayed them with 2 coats of 3M rubber undercoating. It looks good and still holds tight. My wheel wells are riveted directly to the aluminum frame so there is no exposed plywood.

JP

[Updated on: Wed, 16 October 2019 11:43]

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Re: Rear Wheel Well shell seals [message #349329 is a reply to message #349322] Wed, 16 October 2019 13:12 Go to previous messageGo to next message
midlf is currently offline  midlf   United States
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
Senior Member
I had serious water problem. Resealed using some of the techniques listed. Still had leaks. Redid the seal. Still had leaks. Pressurized the coach with the ceiling fans and went around with incense sticks looking for where out-draft blew the smoke around. At the back edge of the back wheel well I found a square opening in the aluminum that was blowing very strongly. Filled that hole and a small spot next to it. Leak stopped. Dry floor happy wife. About 3 years later leak was back. I checked my hole repair and found a very small hole in the caulk. Leak stopped again.

I did the basic leak stop described by others and if it has not been done it is needed. I'm not a great fan of expanding foam. I packed by voids with poly caulk and caused the joint between the floor and wheel well with the same caulk. Also covered exposed plywood with caulk. The second time there were a few small cracks in the joint sealant. Recaulked those. Next spayed the joint area with the magic TV screen door stuff. To date no leaks.

In the RH wheel well there are penetrations for water and water heater drains. Make sure these are well sealed between between the tube and the wheel well.


Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
Re: Rear Wheel Well shell seals [message #349348 is a reply to message #349322] Wed, 16 October 2019 15:44 Go to previous messageGo to next message
GatsbysCruise is currently offline  GatsbysCruise   United States
Messages: 261
Registered: January 2017
Location: Waukegan, Illinois
Karma: 3
Senior Member
Good ideas, thanks

QUESTION.............

the wheel well liner does not seem to seal at the body panel. There is a huge void there.
Do I need to seal that us as well?

I'd have to fill it with something, that is why I suggested expanding foam. After expanding,
it can be easily trimmed to the size and shape you need for the seal.

Where is all that water going if it gets behind the body panel?

I guess I thinking of maybe a car, are they more or less just a space with a liner, no voids???

This is beginning to sound like a really big job. Now that Fall is creeping in, I won't have the weather
I need to do this now but I have to do this first chance I get.

I have used the magic door screen stuff for a water fall reservoir and it worked great, outstanding
with water.
And a plastic kiddie pool, where again, it sealed the crack by just that media itself. If I used it on
the wheel well, I would use a cloth for strength and support for stretch.

I'll have to try to drive in dry weather for now, and thats ok. Unless we get a week of decent weather,
I'll just be collecting supplies for this big job.

I would like to know about the void at the body panel. My thought was to fill it up and seal it.

Thanks for the information.

slc



GatsbysCruise. \ 74GMC260 Former Glacier Model style. \ Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO - UBUNTU VOYAGER - Berzin Auto Center
Re: Rear Wheel Well shell seals [message #349349 is a reply to message #349348] Wed, 16 October 2019 15:52 Go to previous message
midlf is currently offline  midlf   United States
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
Senior Member
By cloth I'm sure you mean Fiberglas. If not please consider it.

Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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