Under carriage question

[JRTJH]

Originally Posted by chuckster57

Be careful using Dicor to seal the edges, since it never really hardens it may gum up the seals. I would use Proflex or another RV rated silicone sealant.

Good Point !!! I used what I had available at the time (it's a 50 mile round trip to the nearest RV parts store)... Fortunately for me, there's no "moving parts or seals" anywhere close to my wheelwells, so DICOR was OK to use "in my application"... When I'm posting, I sometimes tend to forget that not all RV's are built the same and may need some different techniques to accomplish the same end result.....

I used 1/4" thick HDPE sheets from Menards to line my wheelwells. I installed them over the flanges along the outriggers using fender washers and self tapping sheet metal screws, then sealed them with DICOR. It's still in place 5 years later, so I guess I got lucky and haven't had any tire blowouts, and IMO, anything short of a steel tire cage is going to get damaged or destroyed at 60 MPH if a tire tread starts slapping the HDPE...

Here's a couple of photos of my wheelwells.

[Socaldave]

Originally Posted by JRTJH

Good Point !!! I used what I had available at the time (it's a 50 mile round trip to the nearest RV parts store)... Fortunately for me, there's no "moving parts or seals" anywhere close to my wheelwells, so DICOR was OK to use "in my application"... When I'm posting, I sometimes tend to forget that not all RV's are built the same and may need some different techniques to accomplish the same end result.....

I used 1/4" thick HDPE sheets from Menards to line my wheelwells. I installed them over the flanges along the outriggers using fender washers and self tapping sheet metal screws, then sealed them with DICOR. It's still in place 5 years later, so I guess I got lucky and haven't had any tire blowouts, and IMO, anything short of a steel tire cage is going to get damaged or destroyed at 60 MPH if a tire tread starts slapping the HDPE...

Here's a couple of photos of my wheelwells.

That is my exact plan as I read your previous thread on this issue.
What screws did you use on the outside perimeter where the skirt meets the floor, stainless wood screws?
Also did you apply the HDPE the full length of the trailer or just in the wheel well areas. I'm going to line mine all the way front to back.

[JRTJH]

Originally Posted by Socaldave

That is my exact plan as I read your previous thread on this issue.
What screws did you use on the outside perimeter where the skirt meets the floor, stainless wood screws?
Also did you apply the HDPE the full length of the trailer or just in the wheel well areas. I'm going to line mine all the way front to back.

I used standard galvanized (treated) sheet metal screws with a hex head. After installation, I covered them with sealant, so not much chance of corrosion through the DICOR (which is a SLOPPY MESS).... but does serve the purpose. I covered the entire trailer "outrigger area" (outside the chassis rails) with HDPE. Since I had the material, I reasoned, "why not do it all"... I'm glad I did, since road spray from the tires seems to reallly get things muddy and wet from the tires aft. Forward of the tires, I haven't seen a lot of mud being slung onto the surface, but I did all of that as well. On newer trailers, some brands enclose the J-wrap to the chassis rails, so on those trailers, no need to go the extra mile. My Cougar was a "cheaped out/before the image improvements" trailer line, so a lot of the "recent year improvements" were not even dreams back in 2013 when mine was built.

[Socaldave]

Thanks John.

[drycamper]

Hi there.
Didn't read any other replies, so apologies if I'm repeating. Happened to me, and I repaired it with a can of flex seal. Sprayed around edges where I could press existing frayed web material onto flex seal after it got tacky. Then, 2-3 coats of flex seal. Been solid ever since.

[RogerE]

I had two blowouts - same day, first trip. I did as follows:
Step 1: Get some expanding foam filler (Great Stuff $4 @ Home depot). Get a piece of stiff plywood or 2"x8" and wrap it with cling-film/Saran wrap. Prepare a jack. Squirt the filler into the place of the missing foam floor. Immediately jack the board up so that the board forms the bottom of the "mold" of the new foam insert. Make sure it is tight, but do not apply excessive force - just enough to hold the board firmly in place.

When dry, remove the jack and board - the foam does not stick to the cling-film. Cut away any excess dried foam.

Step 2: I used some 3M 77 spray glue, and I cut out a big patch from a woven polyethylene tarp ($5 at Harbor Freight). I overlapped the patch by at least 6 inches all round. I sprayed both the bottom of the floor material, and the patch, then stuck the patch in place. At that point the floor was repaired and (hopefully) waterproof.

Step 3: To prevent further damage I used 23 AWG Galvalume metal sheeting, and had it cut to size. I then screwed the galvalume to the frame using a large number of galvanized/zinc self taping screws. I smothered all the joins and edges with silicone sealant. The galvalume added about 12 pounds of extra weight per side.


When my left tire blew it tore out the wires from the trailer body to the axle. Those wires operate the brakes so I drove home with no trailer brakes. I am about to run an additional wire across the bottom of the vehicle and down the other side to the right brake. That way if I should have another blowout that damages the wires, the brakes will be able to work using electricity running back across the axle from the other side. See the diagram.

Finally I threw out the Load Range E tires, and replaced all four tires with Load Range F tires. These are much more solid, heavy and trustworthy than the Load Range E. (In my opinion.)

I hope this helps.

[Socaldave]

Got all my materials cut today, 1/4" Starboard (HDPE). I'm going to seal the frame side lip with black RTV sealant applied to the Starboard then screw it over the flange. Where it meets the outside skirt and outriggers I will caulk those areas once the Starboard is in place. Going to use self drilling sealed head screws on the frame lip/outriggers and sealed head wood screws on the skirt side. All together I'm adding roughly 50lbs of material to the TT but well worth it IMHO.

[rlh1957]

That good for nothing plastic mesh only keeps customers from seeing the wood. It isn’t waterproof.

I noticed the fabric torn after blowouts.
I cut out the rest and cut sheet metal and screwed it to the wood from in from of tires to behind the tires. Then I heavily applied auto undercoating.
This was all done durning wheels off maintenance.

[CampNBrew2]

Socaldave,
Adding this to your thread as another option for anyone looking. Yours was one of many options I looked into before tackling this with fenders. Any added protection is helpful.

https://www.keystoneforums.com/forum...ad.php?t=51853

[uechikid]

When you say you used

Originally Posted by JRTJH

I used heavy plastic wallboard (1/4" thick) ...

Are you talking about the type that you see in some pubic bathrooms?
I ask because I had a blowout that put a couple holes in the wheel wells and the lining above all four wheels has rubbed off.

[JRTJH]

Originally Posted by uechikid

When you say you used

Are you talking about the type that you see in some pubic bathrooms?
I ask because I had a blowout that put a couple holes in the wheel wells and the lining above all four wheels has rubbed off.

Yes, I bought a 4x8 sheet of 1/4" HDPE "wallboard" from Menards. It's the same stuff that's used in milking parlors, some commercial bathrooms, etc. Really, it's available most anywhere that sells building supplies, especially in agricultrual areas where there's a lot of feed lots, cattle auctions, etc.

Here's the link to the Menards product I used: https://www.menards.com/main/buildin...5882512&ipos=1

It is NOT the same as the 1/8" "pebble finish" fiberglass wallboard/paneling that you find in Lowe's or Home Depot. That might work, but I'd be concerned that it may crack or split in use. The HDPE is far more "rugged and durable". Mine has been on the trailer for 5 years now and other than recaulking the edges, it's as good as the day I first did the job.

[Socaldave]

Also known as Starboard in the marine industry is what I used but still the same as HDPE.

[uechikid]

Is there a reason an automotive spray undercoat isn't used for this purpose?
also, how do I repair these holes? or will the plastic wallboard be the answer to that as well?

[uechikid]

Originally Posted by Socaldave

Also known as Starboard in the marine industry is what I used but still the same as HDPE.

Thanks. Sorry that I hijacked your thread. It didn't make sense to start a new one.🤷*♂️

[Socaldave]

Originally Posted by uechikid

Is there a reason an automotive spray undercoat isn't used for this purpose?
also, how do I repair these holes? or will the plastic wallboard be the answer to that as well?
Attachment 40518

Some have used automotive undercoating but that area you are referencing to needs to be covered/repaired. I elected to cover my entire exposed Darco area with the 1/4" HDPE as we had a ton of it at work. It's not a hard project to do, just takes some time and patients.
Good luck in what ever you elect to do.

[uechikid]

What caulking do you use with HDPE?

[Socaldave]

Originally Posted by uechikid

What caulking do you use with HDPE?

Wipe down any dirt, oil, grease, etc to get a good seal. I used black RTV silicon on mine. You'll need several tubes (10oz) and a calk gun to get it sealed up nicely.

Post # 16 in this thread may give you an idea.

https://www.keystoneforums.com/forum...ad.php?t=51853

[uechikid]

Originally Posted by Socaldave

Wipe down any dirt, oil, grease, etc to get a good seal. I used black RTV silicon on mine. You'll need several tubes (10oz) and a calk gun to get it sealed up nicely.

Post # 16 in this thread may give you an idea.

https://www.keystoneforums.com/forum...ad.php?t=51853

Thanks. I like that fender idea too. But I don't have the clearance.

[uechikid]

Originally Posted by drycamper

Hi there.
Didn't read any other replies, so apologies if I'm repeating. Happened to me, and I repaired it with a can of flex seal. Sprayed around edges where I could press existing frayed web material onto flex seal after it got tacky. Then, 2-3 coats of flex seal. Been solid ever since.

How long ago did you do your repair with flex seal?

[uechikid]

I’m have trouble finding 1/4” sheets of the hdpe. I’m down in the Mobile AL area. Anyone down here know of a place that sells it?