Sunline F2353 Gooseneck Trailer Rebuild

[crburrows]

Posted back in May about the use of poplar for the framing of the back end of my 1987 Sunline F2353 trailer. I have now started the process of dis-assembly and have some photos to share. As you can see from the attached photos the back window leaked and destroyed the frame under the window as well as the floor below. Sunline built this with a galvanized steel belly pan.

[crburrows]

From the outside you would never know anything was wrong. Each window corner has a stress crack/tear. BOAC found out about this the hard way when the Comet jets of the 50's were blowing up in mid-air. Found out that the square-cut windows were inducing stress cracks in the fuselage as they pressurized/depressurized. Simple fix was to radius the corners!

[crburrows]

Dis-assembly photos. Couple of screws were so rusted I couldn't get vise grips to attach to them. Used a Dremel with a cut-off disc to slice a slot to use a screw driver. Worked very well.
The galvanized belly pan goes up the back of the trailer.

Question to forum members is where can I buy the screws shown in quantity? Stainless steel would be preferable. They have a washer style head 1/4" in size.

[JohnB]

Wow! Great progress and thanks for sharing!

The square corners siding rips, yup for sure. The older screwed in windows from the outside may have not helped either. The flexing these campers get for sure can start stress cracks at those square corners.

When they converted to rounded corner entry doors, the flexing never stopped, nor did the cracks. But, in this case, many of the round corner doors have the cracks starting at or through the screw holes in the siding in the middle of the round corner. See here on my 2004 model. Others have reported this also.







On the newer round corner windows, they changed the way the window clamps to the wood frame. There is a flange on the inside that screws into the actual frame and creates a squeeze clamp effect to the wall studs. There are no screws in the wood or the siding like the older windows. They still can leak from putty tape failures and rot out the camper, but at least the siding does not rip.


On a source of stainless screws in quantity. This is where I get mine. https://www.albanycountyfasteners.com/

I converted from the hex head no. 8 screws to a no. 2 bit square drive pan head. Theses https://www.albanycountyfasteners.co...-p/3290000.htm

The no 2 square drive does not strip out like a Phillips does. They do offer no 8 hex head sheet metal screws, but that are also straight blade screw drive combo's if you do not want to convert to the no 2 square bit drive.

I buy in qty to get the price down.

Keep up the good work!! Looking forward to seeing more progress.

John

[JohnB]

If you are after no 8, 1/4 hex steel hex flanged head, AP Products offers them. https://approducts.net/catalog/index...cPath=47_52_55

Find their part number, then search the web. They sell in many places, Amazon and Ebay for starters.

Heads up, the RV screws are normally harder steel and the buggers will not break easy. You can't even drill them short of carbide tipped bits. The standard Hillman zinc sheet metal screw may not be nothing more then low grade steel with a touch of zinc flashed on them. Rust quick and break quick. Granted Hillman does made higher quality too, just make sure you find the higher strength then the standard ones you find in the big box stores.

[crburrows]

Here are some photos of the demo of the trailer's backside. I am amazed at how "flimsy" RV construction can be!

[crburrows]

Some of the floor stringers were spliced with staples and the joint wasn't over any support below!! I cut the floor 24" from the back. The next lateral framing member below is about 28" from the back lateral framing member so my plan is to sister the stringers from the second from back lateral framing member to the back lateral framing member. A 30" long sister member will work and I'll screw it to the good portion of the stringer (after removing the rotted portion).

[crburrows]

Here are the spliced stringers.

[crburrows]

Been sometime since I posted. The work was done in time for us to go camping in NH for the Columbus Day weekend. Got the new stringers installed, put in the insulation, and installed the new floor. I had to cut out about 2 feet of the existing flood due to water intrusion.

[crburrows]

Next up was the sides. I decided to use 3/8" plywood instead of 1/4" luan for the interior. the plywood added considerable strength to the trailer. It looks a bit "rustic" inside and I'll need to consider some kind of treatment.

[crburrows]

After the sides I had to rebuild the back. I left the framing over the window in place and treated the rot with "Total Boat Penetrating Epoxy". The wood soaked up the epoxy and turned into "rock". The lower strut across the back was beveled for the slope of the outer panels and screwed to the upper one.

[crburrows]

After installing the struts I installed the 3/8" plywood back. No ribs have been installed at this point.

[crburrows]

wrong photo!! Ribs are installed!!

[crburrows]

Finished off the inside plywood pieces around the rear window.

[crburrows]

Had to treat the floor to some epoxy as it was a bit "tender". The OSB was discolored so some water had gotten to it. This is the side of the trailer that has a cargo hatch to an area under the couch for storage. That is why I had to cut out the floor along that side. The penetrating epoxy worked well.

[crburrows]

Finally got to installing the table fixture on the back wall as well as the couch. Even with the exposed plywood it looks good. The structure is so much stronger with the plywood. All the ribs and plywood were attached with 1" long #6 wood screws. NO STAPLES!

[crburrows]

Finally the day arrived to put the siding back on. Many thanks to JohnB for his advice (through his posts on rebuilding) on tools and supplies. I purchased an air drive stapler, screws from Albany Supply, and Butyl caulk from Best Materials. I can see why the factory used so many staples. With an air driven stapler it is very easy to over staple.

[crburrows]

Behind each crack is a piece of Eternabond. Again thanks to JohnB in showing how to repair distressed panels. The lower panels on both side of the trailer had pinholes due to aluminum corrosion. Scrubbed them clean with paint thinner then re-cleaned with denatured alcohol and the Eternabond adhered very well!!

[crburrows]

Reattached the fenders and spare tire holder. All done the weekend before we left for NH, which left me the rest of the week to make sure the water, water heater, furnace and other sundry items were OK.

[crburrows]

Twin Mountain, NH