We just bought a slightly used 1988 Saturn T1550

Von Spiel

Member
Joined
May 6, 2025
Posts
16
Location
New Hampshire
We bought a camper. Last year we camped with our friends and decided the tent days are over. I had been watching the webs for years and saw such a deal. Thank you for all the information. I have learned a lot! I have enjoyed hours of research and education on this forum. We are three weeks into the project and I am seriously thinking about taking out the propane. Here is a video.


Today, I learned about new holes and more rain. We live in NH so we have been lucky to have a lot of rain. What a way to test the roof. We have been patching as we go. Going to start on the front tomorrow. I believe I have a mouse living in the front. I am going to give them another night to move out. We have dry parts and wet parts. Thankfully the wet spots are getting smaller. We have tons of weeping screws. We purchased the pocket screw jigs after a failure to locate ours. Thanks for the great site!
 
Hi,

I watched your video; you for sure have a project.

I have done several total restorations before and may be able to help. I'm not sure about your requirements for the project. How long do you want to keep the camper? Do you want to repair all the damage? Do you want to seal it back up better than when it was new, so all your repair work will last?

We are here to help as best we can, and glad to. We are unsure of your needs and wants, but we are happy to offer suggestions to help you with whatever you want to do. And give you some idea of what to expect to meet your wants and needs.

I hope this helps.

John
 
Thank you so much. I have been very lucky to read about and see your restorations and a few others. The sagging roof thread was packed with great information. I have read a lot of great restoration threads way into the night. Your insight and advice has helped immeasurably. We have had it for 3 1/2 weeks now and I feel I went to camper college. I have downloaded all the manuals I could find and have been studying the systems (water, electrical, 12v, etc.) The running lights appear to all work when plugged into our 4Runner. Brakes work and will be checked. We need to buy three new tires, the rims look good and worked well (even though the tires were cracked). We made it 60 miles.

When we bought it, the cushions were missing and some of the floor. A little hard to imagine how it looked. I assume the cushions had a hard backing or support for all the benches had been removed. The seller wanted more for them but we never saw them. Our goals: stop all the leaks, repair and patch holes in aluminum walls, rebuild the floor after we take out the rot, rebuild the benches and beds, make new cushions, and keep all the original systems we can. I believe the fridge and water heater are a little beat up to fix in the initial rehab due to weathering. The fridge vent caps(both parts) have been destroyed. The bathroom looks solid and hope to test the water systems while it is opened up.

We decided to not use the propane yet as we use a portable stove. We just took out the 5 carriage bolts holding the front board that the rotted joists are stapled to. Time to remove the rot and cut back to good wood. We will move the scaffolding to cover the front and slowly remove the siding and the rotted frame. I will use the leftovers as a template for the new framing. The rock shield frame had a nice garden with rich soil that was feeding the window frame leak. Thankfully we have one corner that is dry and original so we have a model. The other side had a hole from the cable/radio antenna. My wife works in Industrial coatings so she is taking care of the leaks. She paints oil tanks. Thanks for all the photos as our walls are just missing the wood. I am not the best at documenting. Time for to reread your posts again! Thanks for all the information.
 
Hi,

It sounds like you're well on your way with the fixing. :)

If you need help, please don't hesitate to ask. In this case, pictures can be helpful; consider adding them alongside the questions, as they can help us see what you are up against.

Best of luck and keep plugging at it.

John
 
Thank you so much. I still re-read all your threads to remind myself, just a bunch of little steps, thousands of little steps. :) We have the front end off and just started to look at the floor. All the floor and more were dust. More damage to the aluminum than we could see. Next step is to clean all the oxidation(steel and aluminum). If there was a plastic coating on the aluminum it is gone. My thoughts are to bend an aluminum sheet in half across the so the fold is facing the front and place one side below the floor and one above and use our new riveting tools.

We are treating the steel with a recipe from my wife(3 parts A, 1 part :cool: only needs a 1/2 cup, very runny. Epoxy preprimer. Then we will need to let it dry for 24 hours. It is graduation weekend and the house is full so I am holding off smelling up the house as the camper is right by the front door. It is also raining on and off. Not an ideal situation for treating steel. After it dries, we will rebuild the floor with the wood we have milled up from measuring samples of the few pieces of solid wood. I did get the wrong size of carriage bolts, I could drill the holes larger but I want to keep all the steel we have left. The trailer is great shape, just needs some tlc and rust treatment. Can't wait to get going, rain, rain go away. Thanks again.
 

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Today's a big day. Applying "the patch" (20 x 83") to the front of the floor section. We made an aluminum brake out of the planks to fold over the patch. Learned that we scored it too deep on one end. Oh well. Has anyone purchased a stapler for reassembly? My wife wants to pick one up at Harbor freight that will work with our pancake compressor. We just don't know what size. We have umpteen big heavy staplers used for furniture but don't know the size, pressure, gun, depth, type of staple we should use. I have pulled at least three types. Off to staple university. Funny that I can't buy it at Staples. Thanks again for this amazing site and helpful people.
 

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A question. I have two rolls of Ice and Water shield in my garage. An extra 120' of it. Has anyone used this for patching? We have a few worn out spots in hard to reach places on the aluminum subfloor. Small holes from screws? We can't fix everything in our short time schedule so that sounds easy. We have just a little over a month. Peel and stick? Thank you for your consideration.
 
The threshold was thrashed so we are really going to stop there. ha ha ha. Milling lumber in the morning. Old table saw is acting up. Fun patching with rivets and aluminum with super sticky goo. I messed up two rivets and was kicked off the riveters spot. The strangest thing is all the play-doh type sealant everywhere. Pounds of it, comes off with a plastic wedge. The new stuff we used a few weeks ago had to be cut off.
 

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Hi, you may be passed this, as it looks like you are, but when they stopped using aluminum on the bottoms of the campers, they started using a product called Darco, which was a brand name for a heavy woven waterproof plastic membrane. Many brands now sell it, and many manufacturers of home appliances use this same heavy polyethylene underbelly material to prevent moisture from reaching the bottom of the floor joists on a slab foundation setup.

It comes in various widths and lengths.

28363162869_24efc34d15_o.jpg


And it is thick, approx. 12 mills thick.
40143334401_153851084d_o.jpg


It was used across the full width of the camper and partly up the walls as a complete wrap. This was 105" wide.
39646839192_9979344bec_o.jpg


You can see here while taking one apart
39646904732_886802c8fd_o.jpg


They also sell a product called "Flex Mend" that is adhesive on one side and woven on the other. It is used to patch the Darco or to tape over seams. This is very thin and not really made for the main barrier itself, but it works well on patching holes and tears. It comes in various widths
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If any of this sparks your interest for your camper, please let me know, and I'll provide more information on what to get, where to find it, and what to watch out for.
 
This looks good:
img_7838-jpeg.1319660


I'll add something here that was done on the newer Sunline, specifically on the front wall siding, which you may not have. On the front wall siding, they used butyl caulk at the top siding joint to create a water seal, helping to retard water from damaging the seam when towing in a hard rain. It helped not to have the water beat around the joint and get into the insulation, etc.

Consider this when you put the front siding back on. This was only done on the front wall. And only on the bottom of the sheet above, so the top lap of the sheet being installed slides into the caulk. You install siding from top to bottom. If you ever need to remove the siding after it cures, warm the joint with a heat gun to soften it and gently tug at the bottom of the sheet. Between heat and tug, it will come apart.

I use SureBond SB-140
39660867552_91a63be24f_o.jpg


39660867792_8479ec6e15_o.jpg


39660867282_047914f56b_o.jpg


Hope this helps

John


PS. What have you decided to do for the corner moldings, doors, windows, etc, when you start reinstalling them to seal them to the siding? This is where most of your damage originated: the sealants used at the time the camper was manufactured broke down, and water weeps developed in those siding joints and screw holes. There are ways to improve the original setup significantly by using better sealants.
 
Hello, Thank you for the information. Perfect timing by the way. We spent a little extra time examining the frame around the door. We noticed the door was attached to dust by rusty screws. How it stayed so stable...a few of the thirty screws held. When we took out the door, what was left of the wall slipped out of an overlap and we almost had a real bad day. Rebuilt the door frame yesterday so back to the floor already. Meanwhile I have been replacing rotted out spots on the framing. Due to time constraints, we are stopping in the kitchen area. I will save that for round 2.

Thank you for the information on Darco. I think I will try the ice and water shield only because we have so much. We have been using it for worn spots and pin holes. Would you place the Darco on top of the aluminum floor below the floor joists or under the trailer? I guess I am confused about the wrapping part. Today there is a 50% chance of rain, so I will be under the tarps today. I ordered the butyl tape and should have it today. I will reinstall a window that I thought was mud encased like the front. I was relieved to see it was dry all around. I can see where there is a straight witness line around the window cutout where a tape may have been. Having a complete wall on one side was a blessing. Also this site, it is my go-to research page.

Corner Moldings. I would love more information. While repairing the inside wall, I noticed pin holes we didn't notice on the first round of roof patching. We don't know what happened to the awning. Was it ripped off in the wind or did they run into a garage door and rip it off the front? On the starboard side or the street side in the front, the molding is crumpled. Checking today the frame underneath is completely rotted away. Yikes, a little more time to expose and remove that. I need to get the floor down so we can stand and work inside. That will speed it up. Thanks for all your information and time. It helps daily.

Cheers!
Brian
 
This looks good:
img_7838-jpeg.1319660


I'll add something here that was done on the newer Sunline, specifically on the front wall siding, which you may not have. On the front wall siding, they used butyl caulk at the top siding joint to create a water seal, helping to retard water from damaging the seam when towing in a hard rain. It helped not to have the water beat around the joint and get into the insulation, etc.

Consider this when you put the front siding back on. This was only done on the front wall. And only on the bottom of the sheet above, so the top lap of the sheet being installed slides into the caulk. You install siding from top to bottom. If you ever need to remove the siding after it cures, warm the joint with a heat gun to soften it and gently tug at the bottom of the sheet. Between heat and tug, it will come apart.

I use SureBond SB-140
39660867552_91a63be24f_o.jpg


39660867792_8479ec6e15_o.jpg


39660867282_047914f56b_o.jpg


Hope this helps

John


PS. What have you decided to do for the corner moldings, doors, windows, etc, when you start reinstalling them to seal them to the siding? This is where most of your damage originated: the sealants used at the time the camper was manufactured broke down, and water weeps developed in those siding joints and screw holes. There are ways to improve the original setup significantly by using better sealants.
This looks good:
img_7838-jpeg.1319660


I'll add something here that was done on the newer Sunline, specifically on the front wall siding, which you may not have. On the front wall siding, they used butyl caulk at the top siding joint to create a water seal, helping to retard water from damaging the seam when towing in a hard rain. It helped not to have the water beat around the joint and get into the insulation, etc.

Consider this when you put the front siding back on. This was only done on the front wall. And only on the bottom of the sheet above, so the top lap of the sheet being installed slides into the caulk. You install siding from top to bottom. If you ever need to remove the siding after it cures, warm the joint with a heat gun to soften it and gently tug at the bottom of the sheet. Between heat and tug, it will come apart.

I use SureBond SB-140
39660867552_91a63be24f_o.jpg


39660867792_8479ec6e15_o.jpg


39660867282_047914f56b_o.jpg


Hope this helps

John
v

PS. What have you decided to do for the corner moldings, doors, windows, etc, when you start reinstalling them to seal them to the siding? This is where most of your damage originated: the sealants used at the time the camper was manufactured broke down, and water weeps developed in those siding joints and screw holes. There are ways to improve the original setup significantly by using better sealants.
Hello,

Thanks again. Here is an update. I got to learn a lot about a lot in this video. Rivets, how not to score aluminum, pocket screws galore! A lot done in my mind. Moving on. Rain stopped and now summer is here. It will go up to the 90s this weekend. https://rumble.com/v6v01mp-camper-3.html?e9s=src_v1_upp
 
Today I learned that I need to rip out one side of the door frame and replace with two solid pieces of wood. I had tried replacing rotted wood and keeping original solid wood around the door frame. I think I measured 20 times and cut once but due to my 4 joint pocket joinery, I lost the plumb of the door on my new side. Looked good! The sun was going down and we had the tape set, ready to install the door on the new frame and had to call it. Nope, not good enough. She is all wrapped up for a few weeks. Wife called her Dolly, like Hello Dolly and I will accept Dolly as the name, but will think of the singer. Super fun project with my wife and I. Time is short and I worry about replacing all the tires, checking the brakes and suspension so we can zoom through the VT mountains. Put back a window after I had cleaned it up. Fun with the new butyl tape and new screws. That worked so well! Two weeks off traveling and will be dreaming of working on it. Thanks for all information. Couldn't be this far, not even close without this site. Next fun, flooring! put the benches back up and making cushions? We have the material and the foam, just don't know what the original looked like. Thanks for all your help. My bed is in the back. I have no idea how it is supposed to look, but I get the platform aspect. I flip and flop so it is unfair to my wife to have to deal with that. 1/8 of a ton spinning next to you might be considered hellish for some. :)
 
Hi Brian,

I watched your latest videos. You are doing great! I see you already have the Kreg Pocket Hole jig. They come in real handy in these repairs.

I'll add some details for sealing up the corner moldings, window frames, door frames, or anything that mounts onto the corrugated aluminum siding. You are seeing what happened many years ago now, and it looks so bad that the whole thing rotted out. It took time for that to happen, and it may be hard to see how it ever started. Here is a top-line sequence of events that outlines how this all unfolds.

There are a "lot" of items that mount to the siding. The siding by itself is good for preventing leaks, but then comes the but... any time a screw or a hole is cut into the siding, that seal to the siding is where the leaks originate. The old putty tape shrinks over time, then fine cracks form, then comes "seeper leaks" as I call it. The seeping water wicks into the wall cavities and then down by gravity, until it hits the bottom of the camper, infecting any wood it touches. And the bottom ends up being wet longer as water from above keeps rewetting it. As water pools, corrosion in the siding can start, and after enough time, corrosion pits and holes can develop in the siding or the bottom. Water can seep out of the holes, but when towing in wet conditions, it can also come in, especially on the front wall. Everything at the bottom of the camper gets more water and rots further, and it all accumulates there.

Here are a few pics to see the early stages, where you can see the leak path. This is a 2004 camper, which is a lot newer than yours. The build of the camper has changed due to advancements in methods, but its method of leaking remains the same.

Here is a front corner molding where I refer to this as a putty tape failure. The putty tape of yesteryear and the type used in 2004, I'm sure, may have different properties and makeup of the tape, but it is still an RV industry issue. This is not unique to Sunline; it is across the industry.

Here is the corner with the molding removed. The black is due to dirt and mold, which have formed as the putty tape shrank and released from the siding and or molding, creating a path for water to seep in. The dirt seeped in with the water, and mold grew as a result of the moisture. Over time, the crack path extends across the full width of the molding, and then water seeps into the walls.
42477533924_f4d2e7001b_o.jpg


Here is the molding that came off that joint.
42291554965_846507c2fe_o.jpg


And the wood rot that came from the leak.
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The same issue of seeping water can occur at any siding penetration point where a hole and screw were made and then sealed with putty tape. The four-corner moldings are often more prone to leaks, as the entire camper flexes on those four corners when towing and making turns. The flexing stresses the putty tape and accelerates the seepage issues. Roof water run off also beats on the corner seams.

Now, how to better build to ward off the problem. I do a multiple-step process to create a lasting seal. I'll show you the outcome of what using the right kind of butyl tape and the right process can create.

This 2007 Sunline 3 years before I ended up restoring it for a friend, the friend reset the front corner moldings himself as a proactive measures using my developed method. To take the roof off and fix the front wall floor water damage, I had to remove those front moldings and I got to see just how good this seal can be.

Here is the back wall moldings on that same camper with the original putty tape. He never made it to the back wall to fix them. See how the tape is not totally bonded to the siding or the molding. It comes off in sheets and loaded with the start of seeping cracks.
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Now to the front corners using high quality butyl tape packed in all the siding low spot corrugations, and the molding itself. This was a real bugger to get apart. I had to heat all of it to get the butyl tape to break itself apart, while it was still adhered to both the siding and the molding. This is the type of sealants we want to end up with. It does not release once compressed, the tape itself has to break apart. This is sort of like a wood glue joint, the glue is stronger then the wood when the joint is made right. The wood itself will crack apart and not the glue.
52004933341_b46e3ee19e_o.jpg


52005462135_3cc61d5661_o.jpg


It was that way down the entire joint on both sides. This is what high-quality butyl can achieve when compressed tightly. For it to seal, it has to be compressed tightly, it will not be a good seal just laying on top, it needs the compression.
52004998823_b0f87996eb_o.jpg


I also added a second step beyond the high-quality butyl. I caulk the exposed edge of the joint where you see the exposed butyl. This helps with dirt sticking to the butyl, but it also creates a second layer of protection to keep the sun's UV rays away from the butyl.

This caulking method can also be used on any siding penetration that you do not take apart to help seal those joints. See here, this is on our 2004 T310SR (our main camper), which was 3 years old when we bought it. I caulked the front corner moldings as a proactive measure back in 2007. There was an actual start of a leak in the lower front corner that I was not aware of, but I sealed it shut. Then, fast-forward to around 2017, when I took the front bottom siding apart to add aluminum diamond plate siding as a heavier stone guard, and I found this.

You can see the white caulk on the siding I put on 10 years ago. The caulk stopped the leak.
52003917202_d9ced01721_o.jpg


52004932591_13fdda3c70_o.jpg


Now you know how the leaks start, and now to how to prevent them.

The corner joint and molding.

After you complete all the woodwork and the siding is clean and ready to install, you install the side wall siding first and bend the tabs of the extra-long siding over the front wall. Staple the tabs in place.

Clean the tabs with a high-flash cleaner (Naphtha or Denatured alcohol) as a final wipe, after the cleaner dries, then put a layer of high-quality butyl down the tabs. Leave the release paper on. Do both sides.

See this link, which will drop you in the middle of a camper restoration showing this process of sealing the front wall siding to the tabs of the long wall siding. 2004 T1950 Restoration Project - (Ugly Picture Heavy)

Next come the corner moldings and how to pack them tight, full of high-quality butyl. See these links, scroll down until you get to the moldings. 2004 T1950 Restoration Project - (Ugly Picture Heavy)

The corner molding ends up like this packed with butyl
50731445226_9c2281df84_o.jpg


Before installing the corner molding, you need to do a final wipe with the high-flash cleaner on the siding of the corner. Then you cut short tabs of butyl and place them into the depressions of the siding. It will look like this.

50713976518_71c9351634_o.jpg


A rear corner:
50776233758_9af80268c8_b.jpg


This link will take you to the area doing the corners. You want to warm the butyl when putting it on, if your shop if at 50F, if it is 75F outside, it's warm enough. You want the butyl to ooze out and then trim it. 2004 T1950 Restoration Project - (Ugly Picture Heavy)

Once the corners are done with the butyl, then you can go back and caulk the exposed butyl. You can use Dicor non-leveling lap sealant or Proflex RV. I have used both, and both are good. The Proflex has more colors and is better at preventing dirt from sticking to it. This post will explain how to do the caulking. Although it shows all the Dirco work, the Proflex works the same way, using a slightly soapy, wet finger to tool it out. Dicor Questions

You can wait to do the caulking, you just have to clean everything to prep for the caulk before applying it.

If you are doing this outside, avoid caulk on sun-hot siding; early morning is preferable. And only apply in about 2 feet of length beads before tooling it out. Hot siding, everything cures too fast and will all glob up. Going only in 2 ft lengths allows you time to tool it. If you wait too long, like 6 to 8 ft of caulking, odds are it will be harder to tool out, especially the Proflex.

On the brand of butyl, see this post. I explained it to another member the other week. In need of some guidance on sealant putty/tape.

If you have a steel building supply house or roofing supply nearby, you want their 20-plus year warranty, good stuff. I linked the GSSI MB-10A I now use, but I used to use Permatite 250H and it is excellent also. 250-H Butyl Tape | Permatite. I just had a harder time trying to buy it by the case, but the tape is excellent. I could really easily get a pallet of it, but I only use about 2 to 3 cases a year. Any commercial building that has specs like the GSSI or Permatite is suitable.

For pin holes in siding corrosion, I use Eternabond Roof Seal tape on the inside of the siding when cleaning it up. This can also work on your bottom metal cover. You stated that Ice Guard is for the bottom cover, and if it sticks, it will be okay on the bottom. But in the siding, it may be too thick, and I'm not sure about the sticking of it. I have used Ice Guard on roof decking, and on the roof, it sticks, but the roof holds it in place. The Eternabond on the siding is thinner, but it will definitely stick. See here on the siding holes patching. 2004 T2475 Repair - Project Camper No 2

Edit: 6/21/25: I forgot to add on the siding corrosion repair, after the Eternabond Roof Seal is applied on the inside, once the siding is installed on the camper, I use Proflex RV clear on the outside of the exposed gray Eternabond to add an extra layer of a seal and to keep dirt from sticking to the area. You can apply the Proflex before installing the siding if you have time for it to cure before installation. Also, use a light, soapy, wet finger to tool out the Proflex.

You are doing great! Hang in there, in time, it is all repairable. :)

I hope this helps.

John
 
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Thanks for posting this; a lot of good info. We just got a 1989 sun line nomad; it had a soft spot by the bathroom, turned out all the wood in the floor from the axles back is wet and rotted. I’m doing the same job you are. But the aluminum under belly is worse than yours. I need to find replacement aluminum and section it into the under belly. My family really enjoyed the trailer; and other than the floor the trailer is in great shape. I really hope we can save it 🙏🏻
 
Wow! Thank you so much for all the information. We are back at it tomorrow morning. Interesting to see how everything held up. I really appreciate it. I read it over and until something clicks. Working on the door frame tomorrow and maybe a little flooring. Three people tomorrow. Thanks again!
 
Thanks for posting this; a lot of good info. We just got a 1989 sun line nomad; it had a soft spot by the bathroom, turned out all the wood in the floor from the axles back is wet and rotted. I’m doing the same job you are. But the aluminum under belly is worse than yours. I need to find replacement aluminum and section it into the under belly. My family really enjoyed the trailer; and other than the floor the trailer is in great shape. I really hope we can save it 🙏🏻
Good Luck with it. I am sure you will find a solution. We are going to start on the floor today. I left the back part for more fun later.
 
Thanks again for all the information. I got back home after a two week vacation, I was attacked by a dog while looking at a racecar in a private shop, bad dog. So we returned after our vacation to 95º with 90% humidity and I couldn't jump in a pool or any water to cool off. Thankfully all healed up and no longer wake up in the woods. Here is a quick video on our updates. https://rumble.com/v6wa7hm-camper-4-heat-wave..html
 

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