T@B 400 Alde corrosion

barbarella20722

I'm in the process of fixing the Alde corrosion issue on my 2020 tab 400 BL. Because there doesn't seem to be much information here for the 400. I was asked to post my progress here in hopes it could be useful to other owners. 

  I noticed a bulge on the hose that houses the check valve in the Alde compartment last week. Knowing what this means, I started slowly disassembling areas that have convectors, starting with the bed. I changed the fluid (yellow with yellow) last spring, 3 years after purchase. 1 year late, because I didn't know you were supposed to do it every 2 years. My mistake. Though, given the degree of corrosion, I doubt it would have mattered.


Mark Turney's hypothesis about hoses under downward pressure being far more susceptible to extreme corrosion, seems to be spot on. 


I then moved to the one under the wetbath. I was able to get the left hose off and clean it. Then reinstalled the hose further out on the stub. So there's less surface area (in theory) being exposed to the glycol. I haven't tried the right side yet, but I'm not sure I'll be able to get it off. So I'm saving it for later.


Next was the kitchen. Pop off the plastic covers, back out the screws (Roberts head) and removed the boards. This one is almost pristine. 


Now I'm to the dinette. Having to dismantle this area took some effort. I'll probably check the convectors on either side. Then deal with the center.

There's a lot going on behind the center dinette. So I need to really think about how I'm going to go about removing the top. Since it seems to be more than just screws holding it together. 

  And this is where I'm at now. I'll post more pictures and info on my experience as I get further along. 

barbarella20722

I'm going to try and post pictures as I go to make things a little easier for me. 






To get to this I had to remove the fabric board and the plywood piece behind that. I backed out the pocket screws (Roberts head again). Removed the two, 2" Phillips screws that I assume went into the frame. The convector and wiring harness are screwed in from the back. You'll need some kind of low profile ratcheting tool to get these out.

I happened to have this already. It did work, but barley. Quite a bit of glycol did come out from the front hose. So try to put what towels you can under it. 




Pieces I've had to remove so far, JUST to get to the convectors.🤨

barbarella20722

I now have all the convectors removed except the one under the wetbath. I coated the stubs with the miracle paint and will leave them to dry overnight. 


The passenger side was easy. The hose was too long, pushing down on the stub. I may have to cut some off the end so everything fits properly. I'll see how it all looks first.


The center top was attached with pocket screws from the inside and you can't remove it in one piece because the wires are screwed to the back face. So I did what I had to. That's all I'll say about that.



The hose on one side wasn't quite "straight on". So it needed cleaning. 

 The front hoses had a surprising amount of glycol still in them and it made a bit of a mess. I'm seriously thinking about putting another low point drain up front. IF I'm able to find a suitable location. Tomorrow I'll slowly start putting things back together and figuring out a couple access panels so I can keep a better eye on things.

  It's a big, messy job, but it's not hard. Now if something went bad on the actual Alde unit. That's probably something I'd nope out on. Hopefully these pictures will help other 400 owners that may run into this issue in the future. 

Bill&Suze

Thanks @barbarella20722, this has been an eye opener and an in depth look at a daunting project that a 400 owner may face. It would be helpful, if you haven't done so already, to mention the name of the miracle paint you decided to use.

barbarella20722

@Bill&Suze it's literally called "miracle paint".😉 It was recommended by, Mark Turney. The brain child behind why this is happening. As far as I can tell, he nailed it.

I forgot to mention that on the rear convector. I cut two fins off either side, pushed to mounting bracket back and cut the portion with holes in it off. I used a simple pipe cutter. You can get it in the plumbing department at any hardware store.

fstop32

@barbarella20722, I am feeling your pain!  I went through all of this with my 2015 T@b, it was my post that got that enormous "corrosion" thread going a few years back.  All the deconstruction, diagnosis and repair was quite the project.  My 2015 was a much simpler build than what you are dealing with on the 400.  Once I pulled it apart I saw things I would have done differently and did so on the rebuild.

I wish I'd known about the Miracle Paint at the time.  I'm due for a glycol change now and I will be reinspecting each joint in the process and will add the paint to all those connection points. I did what you did with shortening the stub ends and removing a few fins, however since they are aluminum I slowly cut the tubing with my carbide tipped chop saw (and safety glasses).  I felt it made a cleaner cut without putting pressure on the tube and possibly deforming it which would create a space to pocket the glycol. 

Great job documenting your process, I'll be following along.  Hold firm, there is a good end to your work!

pthomas745

@fstop32 we are eagerly waiting to see your results. I feel like I'm part of one of those long term health results surveys!

fstop32

@pthomas745, I know that feeling too!  I'll probably wait till the weather here cools down just a bit before I dive back in but I'll post what I find!

Artie101

I am doing mine today.  I have a 2016 T@B 320S Outback Edition.  I have a heat convector across the back and under the p/side bench only.  As the low point is on the lower convector under the p/side bench, I took that hose off to drain the glycol in addition to opening the valve thingy at the Alde to drain what I could from there.  This worked well.

When I removed the wood panel that protects the convector on the P/side, I discovered that Nucamp failed to put 2 hose clamps on.  So I added them closer to the end of pipe.  Surprisingly and interestingly, there is no corrosion here.

Then I put the protective, wood panel back in place.

I could see some minor bulging (compared to other's pictures I've seen) at the connections in the back convectors so knew I had to remove them. It was simply removing a bunch of small screws in a really awkward place.  I had to remove the top one first (of course), and then I had to remove the hoses to get at the lower screws on the lower convector, what a pain, this is a tight space but doable.

Here is what I discovered...

My question is, how did you clean these pipe ends up?  I'm not sure if there is a chemical I can and should use or sandpaper?  Please tell me how you cleaned yours up.

I posted what I have done here hoping that it might help others with there 320's.

Thank you very much for your post barbarella20722

barbarella20722

@Artie101 the tougher bits I scraped off with the utility knife. Then took a green scotch pad to it. 120 sandpaper if that didn't do the trick. Then scotch pad again to kind of buff it. Wiped with damp cloth, let dry. 

Interesting that you didn't have corrosion on the hoses that were bent. I think as more people start taking on this problem themselves. We'll slowly start getting a better picture of what's really going on.

  In the meantime, I'll just do what I can with the information I've gathered so far and hope for the best.🤞

barbarella20722

@fstop32 I'm glad you started that thread! It's been extremely useful. And yes, I used a pipe cutter and there is a tiny bit of a taper on that one convector. I hope double clamping and miracle paint saves me from regretting it. Only time will tell.

Artie101

Barbarella20722, thank you very much for getting back to me so quickly.  I used your advice and am happy with the result. The hoses that were bulging a lot more, strangely had less corrosion, but still significant enough that I felt I should trim the ends off of the pipes.  

Somebody, I am assuming during construction, made a mess of the end of one of the pipes that I trimmed.  It was slightly compressed at the end and had what appeared to be a very minor line around it, possibly from a pipe cutter.

What I cut off...

The finished ends after cutting, cleaning and painting with 2 coats of Rust-Oleum Self-Etching Primer...

Now that I have done this and been through it, it is not so bad.  I'll monitor my connections regularly going forward, change my Alde fluid regularly and address any signs of corrosion right away.

fstop32

@Artie101, like @barbarella20722 I took the worst of it off with a utility knife and then used steel wool, scotchbrite pad and a fine brass bristle brush.  I wonder if the lack of corrosion on the two ends missing the clamps was due to a nice snug fit of hose to stub with no clamp pressure to pucker the hose, that perhaps didn't give a place for glycol to start sneaking in between the hose and stub.  Maybe NuCamp is onto something there    It's a low pressure system but I'm surprised you didn't have any slow leaks there.

Also, I had those "crimp lines" on the ends of some of my convectors.  I bought two new short convectors from NuCamp when I rebuilt mine and I noticed that they both had an end that had that crimp.  I think when they cut the tubing at the factory (Alde I assume) the tool they use to hold the tubing is putting too much pressure on the aluminum tube and crimping it.  I also noticed that the worst corrosion I encountered was ALWAYS on the tubing end that had that crimp, creating a pocket that caught glycol and let it sit there unrefreshed no doubt.

barbarella20722

@fstop32 I see what you're talking about. A couple of mine had a kind of crimp as well. Though, it was mild by comparison. I feel like I'm in the middle of an R&D project. I honestly don't know if what I'm doing will "solve' the problem. That's why I'm going to do my best to create better access to them in the future. Not exactly sure how yet. However, sharing detailed information here seems like the best way to go. Even if I have to share my embarrassing failures.😉 

 And yes, I'm Very surprised it wasn't leaking yet. I must have gotten to it just in time. 

barbarella20722

@Artie101 I can see how glycol could creep it's way into a small imperfection like what's on that stub. Then it crystallizes and begins to expand. Maybe there a few different things at play here?

barbarella20722

I got two convectors installed today. Kitchen and DS dinette. 


Originally one of the hoses was too long. Pushing down on the stub.


This is what it looks like now. I cut the hose to fit, moved some of the pipe hangers, fastened the overflow line out of the way, and put a piece of scrap board to help support the thin cover that will go back over it. 

fstop32

Ahhh, it brings back fond memories!    Nice work!

barbarella20722

First access point. I modified the dinette a while ago to a full-time couch configuration. I cut the plywood in half and used the back section as an access door. I'll attach the front portion after I connect the convector back up. Then set it back up like it was before... after I do a leak test, of course.

 For the center face, I added height, then drilled 1" holes for heat to escape. Since there is no longer a rear gap at the top. 

fstop32

This is exactly what I got into when I had to mostly strip out my 2015 to get at all the Alde plumbing.  I found all sorts of projects and things I wanted to alter/upgrade!

barbarella20722

PS dinette access: 

Started with a hole saw towards the front. Used the oscillating tool to cut the rest out. I put a board behind to protect the wall and wires. 

I used bolts, washers and nuts tightened down to create mounting posts that can go through the new plywood access panel. 

Drilled holes to run the bolts through. Washer and nut on the bolts, then tighten down. Positioned the board/cover and screwed it in. I also drilled two 1" finger holes. In the future, I can loosen the bolts/washers and unscrew the board to gain access to the convector without taking down the large panels that frame the window. 

pthomas745

This is Tab Merit Badge worthy stuff!

barbarella20722

@pthomas745 I'm not so sure I put all the right screws in the right place when I reinstalled the big wood window panel. So you might want to hold that thought.😏

barbarella20722

@pthomas745 I was wondering if I would have this problem, and low and behold. I've started filling the glycol tank. Got about half gallon and the tank isn't draining anymore. I'm going to assume the pump is dry so... Is there a way for me to prime the pump? Lifting the front of the trailer may help but not sure it will get enough back there. I have the bleeder open in the bathroom too. Any thoughts?

Edit: Nevermind. I got it figured out.😉
Letting it run for a bit.

barbarella20722

Filled the glycol, let it run for about 45 minutes. No leaks, blead the line and everything seems to be running well. Now to start putting things back together. 


Cleaned up the wires first. I realized after I started rebuilding that I absolutely could've made this simpler, but I was already in the middle of it and would have needed more hose. Regardless, it works. I'll grab a couple hose hangers to stabilize them to the wall and straighten out the bend on the right a bit. I don't mind the convector being off center. I'm sure it will still get hot as, Hades back there. And that's it!.. Hopefully for a long, long while.🤞

fstop32

Don't you love it when a plan comes together    Nice job!  I remember how it felt to have it all put back together and working.  After a little sleep I felt good about my new depth of knowledge I have in my T@b!!!

barbarella20722

@fstop32 indeed! Last thing related to my little, Alde adventure. I used bolts on the long wood piece in the bed area. No more fighting with screws if I have to remove it again. Now I can work on doing a few small updates to my solar situation. Which is why I was in the Alde compartment in the first place. 

Thank you everyone for all your help! Especially, Mr. @pthomas745 Not all heros wear capes.😉😁

fstop32

Happy Trails!

barbarella20722

@fstop32 and @pthomas745 sorry to bother you both again. Well, I had a feeling everything was going a little too smoothly. It seems the automatic bleeder valve has a slow leak that started last night. I've gone through some threads and tried gently knocking on it, but no luck. I can't see any glycol inside the trailer and the expansion tank seems fine as well. It had about 2" of fluid in it last night but is empty this morning. How difficult is it to replace the bleeder and does anyone have any other suggestions on what might be the problem? Thank you!

How difficult is it to replace and is there other things that could be going on? It was a extremely hot yesterday but I would think a properly functioning system would be able to handle it. 

Sharon_is_SAM

The Alde auto bleeder valves is a  frequent offender and can account for your glycol loss.  We had ours replaced several years ago.  Just to make sure, what is your glycol pump set at on the pump, not at the control panel whose function is inoperable.

barbarella20722

@Sharon_is_SAM I haven't run the Alde since I filled it several days ago. Here are pics of the two pumps. 

barbarella20722

@Sharon_is_SAM zooming in on the pictures I noticed the rear pump was set way too high. I dialed it down to #2.