Removing fresh water tank -- 2014 25FB part 1

[GammaDog]

I've received so much good advice here that I wanted to document and share my experience replacing the fresh water tank on my 2014 25' FB. I found little documentation on how to accomplish this and I'm hoping this post helps someone else facing a water leak.

Our leak started on I25 in Denver when traveling with a full tank of water on the way to dry camp in RMNP. Hey, Colorado, where old pavement meets new in a work zone the proper transition is a smooth patch, not a ditch! Anyway, I was losing about 3 or 4 gallons a day, slow enough to get home without emergency repair, but not slow enough to ignore.

I knew that the fresh tank was in the black plastic box between the axles, I did not know much more. That tank box also contains the low point drains on my trailer. That was easy to see, but the implications of that placement did not become clear until well into the removal process.



1. Preparation and inspection:

I first raised the trailer by pulling both sets of wheels onto three layers of 2x lumber. I used two 2x12s with a 2x8 on top. My tank was totally drained from the leak. Naturally, opening the drain petcock or pumping the tank dry would accomplish the same. Regardless of the method, the tank should be empty before proceeding.

Based on my experience, the proper process of diagnosis and, if necessary, removal begins above the tank. On the 25FB the tank connections enter the trailer in the space under the fridge which is on the street side. Remove the door to the storage space below the fridge and remove the kick panel that separates the storage space from the mechanical space behind it.

IMPORTANT NOTE: There was no fiberglass insulation visible in that compartment, but I knew after working in there for a while that there was lots of loose fiberglass present. That space should be vacuumed to remove contaminants and you should wear protective gear (long sleeves, gloves, particulate mask) when working in that space. From now on, I'll do the same in any mechanical compartments in the trailer.

An inspection on my tank was inconclusive, so I did have to remove it to learn more, but your issue may be diagnosable, and even repairable from above. Here's what you will be able to see when you get your head into the compartment:

1. Inside the black box that is fully visible below the trailer is a translucent white plastic tank.
2. From the top of the tank down are the following connections:
a. The vent which is a clear plastic 1/2" tube attached to a barbed elbow screwed into a flange on the top of the tank. This tube terminates at the small screen behind the water fill door on the street side of the trailer.
b. The fill line which is a large, ribbed tube that is clamped to an elbow which is screwed into a flange near the top of the street side end of the tank.
c. The drain line leading to the drain petcock on the outside of the black tank box. This line is a mix of 1/2" PEX and clear plastic beginning at a barbed elbow screwed into the tank at a flange on the street side of the tank near the bottom. (Note: Near, not at or on the bottom. The tank never fully drains through the petcock. Never!) There is an additional elbow in this line which creates a zig zag pattern and presumably allows the tank to move a bit without breaking the drain line.
d. The water pump feed line which is 1/2" PEX attached to an elbow that is screwed into a flange immediately adjacent to the drain fitting.
3. Also attached to the outside wall of the tank on the street side is a flexible printed circuit board. This is the water level sensor. It is connected to the trailer wiring with two wires.
4. Finally, this space contains the low point drain risers. These two, vertical, 1/2" PEX pipes connect to the brass petcocks on the underside of the black tank box and to the trailer's hot and cold distribution system in the space under the fridge.

The tank box is lined with 1/2" styrofoam panels for cushioning and insulation. I'm not convinced that 1/2" of low density styrofoam provides much cushioning or much insulation, but that's what is there. The ends of the water tank box are packed out with several layers of styrofoam wrapped in duct tape to limit the distance that the water tank can shift in the larger tank box. Crude, but evidently effective.

The space is difficult to photograph, but here are three shots that show what you might see:





Of these fittings, it would be possible to tighten the connections for the water fill line to its fitting or the vent line to its fitting without removing the tank. It may be possible to replace those fittings if cracked or loose also. If either of those fitting are causing your leak, they wouldn't leak for long before the water level fell below the point of leaking and the leak stopped. I can not envision fixing leaks at the drain or pump feed fittings effectively without removing the tank. If someone has accomplished that, please add to this thread to point the way!

Next post for more...

[GammaDog]

2. Removing the tank:

I recommend disconnecting all of the connections described above before moving under the trailer. The one exception to that is the drain line. Both ends of that line are attached to components that will be removed as a unit.

1. Cut the wires to the tank sensor. For reference, the blue sensor wire on my trailer connects to the blue wire in the trailer. The black wire from the sensor connects to the white wire.
2. Remove the band clamp for the water fill line and remove the line from the tank fitting by twisting and rocking. The joint was treated with a non hardening sealer, it's a bit messy.
3. Remove the band clamp for the vent line and remove the line from the fitting.
4. Disconnect the water pump feed line. On my trailer this was easily accomplished since it was the only line with a screw off fitting (specifically, a fitting similar to those used in garden hoses) which joined the PEX riser to the flex hose leading to the water pump.
5. Finally, and most difficult are the low point drain risers. There are no disconnects on these lines. They are entirely PEX and assembled with copper ring connections. It appears that the lower ends of these lines are threaded brass fittings. It may be possible to unscrew these, but the space was too distant and cramped for me to secure a wrench to the nut inside the tank box then go outside to see if the fitting below would unscrew. Knowing that there are various 1/2" connections available, and having no PEX tools or experience, I elected to cut both lines about 2" from the upper connection point into the trailer's hot and cold system. Small electrician's cable cutters work great for this purpose. (Note: since writing this, I have learned from afk314 that his similar trailer needed a low point drain replacement. The retaining nuts holding the brass drain fittings on his trailer to the black fresh water tank enclosure could not be removed because they were blocked by the copper PEX retaining tings that secured the low point drain risers to the drain fittings. Thanks, afk!)

With the disconnection complete, it's time to move under the trailer. I found it very helpful to have two 8' ratchet straps (I used the 1" nylon belt type). Thread these over the top of each axle with one strap halfway to the street side of the tank box and one halfway to the curb side. Join the free end of each belt to its respective ratchet mechanism and snug, but don't tighten them. These straps will hold the weight of the tank box and tank once the bolts are removed and can be used to lower the assembly to the ground.

The tank box is held to the trailer with 14 bolts. These are located on the front and rear edges of the tank box. Both edges have a metal strip that contacts the flange of the tank box. There are seven bolts in the front and seven in the rear. Neither side edge is bolted. Every other bolt beginning on both outside holes supports an additional fitting which is a "C" shaped metal support strap that goes completely under the tank box from front to rear. There are four of these straps. Interestingly, none of the bolts on my tank had lock washers or flat washers. All were still snug after 4 years and about 30,000 miles of travel. Remove all 14 bolts, starting with the ones that hold the "C" straps. Once the bolts are out, set aside the two metal strips and the four support straps. The tank box with tank in it can be lowered to the ground using the ratchet straps. It can be moved across the ground to extricate it from under the trailer. Remember that the low point drain fittings are there. I used a moving blanket as a surface to work from. I placed the tank box on the blanket and dragged blanket to avoid damaging the drains.

See next post for more...

[GammaDog]

3. Inspection and repair

The trailer was stored at our son's house but I took the tank home for the next steps.

I disconnected the drain line so I could remove the tank from the tank box for further inspection. The first thing I noticed was that the tank box had lots of manufacturing scrap around and even below the tank. Most concerning were two pieces of aluminum sheet that clearly were scrap from holes being cut in the skin. Both were sharp enough to cut a wire or conceivably to damage the tank although neither had done damage in my case. Also in there were rivets, rivet shafts, a coil spring, wire, etc.. Messy, Airstream! Very messy!



I placed the tank on a solid table (remember, this tank weighs over 300 pounds when filled, and you are about to fill it). The next step is intended to be a test of the tank, not the table on which the tank sits. Plug the drain line and fill 'er up! Mine started leaking where the fitting for the the pump feed line met the tank body. Here is a pic of the fitting after I twisted it and it came right off:



Based on other posts on the Forums concerning water tank repair, I considered this failure to not be a candidate for repair. I ordered a new tank and tank level sensor (they are separate parts) from my supplier which is Colonial Airstream in New Jersey. I've had first rate service from Colonial and would recommend them. Both parts shipped directly from Airstream. I had both in under a week by UPS Ground. The tank ships without any fittings. If you have any damaged fittings on your tank you will need to order them separately and individually. I understand that some people reuse the sensor. Although I chose to order a new one, I later tried removing the old one with a putty knife. It came off easily and stuck to the new tank. If you are looking to save $87, go with a tank only and reuse the old sensor.



The fittings need to be removed from the old tank and placed in the corresponding locations in the new. The factory had used a non-hardening sealer on all threaded and slip connections. This was effective at preserving the integrity of the joints and was appreciated as I disassembled the system and didn't have to cut out hardened sealers or cement. I chose to use RectorSeal T plus 2. It was the first joint sealer I found that was recommended for essentially every type of metal and plastic, was non-setting, suitable for potable water systems and recommended by the manufacturer for both threaded and slip connections. Use it liberally!

The tank goes back in the tank box. I discovered that the styrofoam under the tank had a cutout for the plug on the tank's belly. That cutout wasn't in the right place. I created a new one. The tank I removed was duct taped in place, so I replicated that. Keep the tape loose so the tank box flanges can be wiggled enough to align with the holes. Reconnect the drain system to the petcock.

Next post for more...

[GammaDog]

4. Reinstallation and testing:

Reinstalling the tank was straightforward. Slide the box to below the opening, use the ratchet straps and raise into position. Check for interference, especially wiring and the drain petcock. I chose to make the electric and plumbing connections inside the trailer first before bolting the tank box in place. I'd recommend making the hardest reconnection first. For me that was the fill tube because there wasn't much room to maneuver a wrench to tighten the band clamp.



If you cut the low point drain risers, reattach them using slip connections. I used John Guest SpeedFit couplers (1/2" don't forget the sleeves to reinforce the PEX). I had never used them before and was delighted.



Quick, easy, zero leaking at the 24 hour inspection even with the pump left on. Best of all, my low point drain system now has a quick release in case some poor fool (not me!) ever has to replace the fresh water tank on this trailer! I soldered and shrink wrapped the tank sensor wires. Bolting in was easier than expected. I reversed the unbolting process. I secured the front metal strip with the three bolts that do not also secure the "C" straps. Corrosion on the metal identified its original orientation which I honored. I did the same for the rear strap. Next went the "C" straps with the fronts bolted then the rear. Every hole aligned perfectly and easily. The final step is to fill the gaps around the corners. For that I used 3M StripCaulk, a butyl rubber filler that is pliable, sticky as taffy and non-hardening. I'm going to carry this stuff in my box of glues, paints and sealers from now on. All four corners of the tank box need to be inspected and plugged if any interior is seen. Remember, the corners of the tank box are adjacent to the tires. Rain water will get in during travel.

I filled her up, found one minor leak (where the tank fill tube joined the fitting... removed, cleaned, resealed, connected and made sure the band clamp tightened around the ribs of the tank fitting). I rechecked everything in the compartment after 24 hours then replaced the compartment kick panel and door.

Finished. Elapsed work time about 8 hours. Could probably do it again in 5 and hopefully these instructions can help someone else save those three hours.

[GMFL]

Great post! I did the same thing on my 2014 23D some of your photos did not show up.

Here’s my blog post
http://www.airforums.com/forums/blog...lacement-2929/

http://www.airforums.com/forums/blog...t-part-2-2930/

[A W Warn]

Excellent post!
Thank you

Repost the last 4 photos please

[GammaDog]

Thanks, guys. It took me four tries to post the pics. It seems like there is a pic count limit or maybe megabytes/post? Anyway, thanks for the quick feedback. I sure wish my searched had found that blog post, GM!

I have more pics, but mostly different angles of what I posted above. PM me if something isn't clear and needs a new pic. To all readers... since there isn't a guide book on these things, it's up to us to build it as we work. I have zero confidence that I did this the best way possible. But if you add your experience in additional posts to the thread maybe together we can describe the best way.

As afk314 (noted in one post above) observed, Airstreams as often built using techniques that make manufacturing easier... and service later more difficult.

[kpm]

Great post! This will be very helpful for anyone else needing to do this. The only thing I would add is to carefully check the John Guest quick-release fittings for leaks. I use them on a reverse osmosis system at home and I’ve had probably 5% of them leak at first. Sometimes recutting the pipe helps but other times I’ve had to replace the fitting.

[BoeingJet]

Contact Airstream Customer Support. They are fantastic about providing instructions, free of charge. I had a tank issue, which I had my mechanic fix; based on AS provided instructions.

[pteck]

Nicely done, and definitely appreciate you documenting this.

Given the failure, I assume the damage was caused by the shock of running through a ditch, rather than any impact to the water tank?

Wonder if there could have been any mitigation? 15" or 16" wheels? Lift? Guess there's always a bigger ditch to cause mayhem.

[GammaDog]

Thanks, Boeing... I didn't know that.

Pteck: It's all speculation, of course, but there is a clue in that one pic where the flange that was leaking is shown removed from the tank. It twisted off in the process of removing the ell fitting that was in it. It appeared to me that either the original plastic weld that connected the flange to the tank body was not sound and eventually gave out or the weld had been good and the ell fitting was overtghtened and damaged that joint during original assembly. The tank never leaked until the "Denver Ditch". It was a bad one. At the time, I was running 16" Michelin LTX M/S2's at 70 psi and probably doing about 50 mph in the construction zone. If that flange was already weakened, I think it just met its match that day. For what it's worth, it had survived multiple trips across Louisiana. That's saying something about its character. But that day the poor, brave, little thing just couldn't hold on any longer.

[Mattirs]

Originally Posted by GammaDog

But that day the poor, brave, little thing just couldn't hold on any longer.

Yup, :,-(

[rfequity1]

this post is excellent. I just picked up my new fresh tank today and will replace in the coming months since mine is now leaking pretty bad from the drain spin weld.