Tell me why I shouldn't do this....

[Al and Missy]

Hint - you are already too late.

I need to replace my black tank drain valve. I decided, based on A W Warn's excellent post here, to do both valves and clean out my black tank flush spray head at the same time.

I originally planned to use HF shears and cut an access port in the pan but became afraid to cut blind and also discovered that to access both valves I would have to cut pretty far into the center of the trailer.

So I decided to drop the pan, and then maybe cut an access panel. I have the trailer up on ramps but still can't easily get to the line of bolts at the front of the pan.

So I decided to partially drop the pan. I pulled the bolts on the back, center, and sides and let the front wall bend to drop the rear of the pan. This gives me enough access to do everything I need to and all I have to do is jack up the rear of the pan and replace the bolts I removed.

Does anybody see a problem with this? It was so easy I think I'll not even try to make an access panel.

BTW, I can't believe the scraps of Styrofoam they used to haphazardly shim out the pan on the bottom and sides, just a few good rectangular pieces and a bunch of broken scraps. The wiring in this area is a rat's nest, including the heavy gauge 12V wire for the power stabilizers. I'll clean that up too.

Al

[GCinSC2]

Al,

A box of assorted band aids is on its way to you.

Good luck.

Gary

[azflycaster]

And a tetanus shot...

[Al and Missy]

Thanks a lot guys....

I did flush the black tank really well on the way back from a rally. I could actually see the mottled color of the plastic tank. I had less than a teaspoon of nasty stuff come out when I pulled the valve.

I must have been doing something wrong the last two years. I have been using the "geo method" (Calgon and Dawn) occasionally in both and WalMart citrus chemical for the black tank. The old valves look almost new, as in the owner previous to me must have had them changed. They are both very hard to work. The gray valve will close, the black has always been difficult due in part to the offset operating rod, but now will not close at all. I can't see anything wrong with them. I think I'll buy rebuild kits and keep them as spares. The tank adapters look new. All parts have new looking SKU stickers on them.

I'm off to Lowes for a 3" street ell and a 3" sewer tee.

Al

[GMFL]

I just did my fresh water tank and I agree the styrofoam was crap, I re did mine

[Al and Missy]

Originally Posted by Al and Missy

Thanks a lot guys....

...

I'm off to Lowes for a 3" street ell and a 3" sewer tee.

Al

No ABS fittings available anywhere in Melbourne. Ordered from Amazon. Why use ABS instead of PVC, anyway? Is it stronger?

Al

[Al and Missy]

Originally Posted by GMFL

I just did my fresh water tank and I agree the styrofoam was crap, I re did mine

I should show you a picture of mine. Your before picture is several orders of magnitude better than mine.

[DreamStreamr]

Hi Al,
Gosh, wish I was working on my black tank too. I'm replacing my furnace control board - is that sort of the same thing? LOL

Since you mention offset on linkage I'm pretty sure you don't have the exposed Valterra dump valves, right? Upside of those is very easy change out. Downside is susceptibility to damage from road gators.

[Al and Missy]

Hi Jim (and Debbie),
No, I have the buried Thetford ones. The offset linkage is only on the black valve. On my 30 slideout the actual valve operating rod is very close to, or behind, the rear tire. I replaced them with more Thetfords as I read good and bad about both Thetford and Valterra, but less bad about Thetford. I also didn't want to risk leaks when converting to Valterra.

Al

[featherbedder]

Originally Posted by Al and Missy

Thanks a lot guys....

I did flush the black tank really well on the way back from a rally. I could actually see the mottled color of the plastic tank. I had less than a teaspoon of nasty stuff come out when I pulled the valve.

I must have been doing something wrong the last two years. I have been using the "geo method" (Calgon and Dawn) occasionally in both and WalMart citrus chemical for the black tank. The old valves look almost new, as in the owner previous to me must have had them changed. They are both very hard to work. The gray valve will close, the black has always been difficult due in part to the offset operating rod, but now will not close at all. I can't see anything wrong with them. I think I'll buy rebuild kits and keep them as spares. The tank adapters look new. All parts have new looking SKU stickers on them.

I'm off to Lowes for a 3" street ell and a 3" sewer tee.

Al

I found hard to pull valve open or close. saturated rod w/ penetrating oil now little easier to open & close.

[Bill M.]

I just finished replacing my valves and leak checking. I have not put the access hole cover back on yet. I just cannot imagine having enough room to work with the pan hanging down still supported on one side. I know I was straight up under mine a lot of the time and still could only get a few fingers on the screwdriver. I worked with the wheels on the ground on one side and on a couple of 2x8's on the other so not much room for me.

This trailer already had a hole cut by Airstream when they rebuilt the valves 11 years ago. I really wish Airstream had changed the valves instead of just putting in the kit. I cut a hole in the other trailer using the HF nipper. Not pretty or much fun but it worked.

I put in new valves. The body of one of the valves was cracked in at least 3 places. I rebuilt the valves on my other trailer but am really glad I replaced these instead. It is just too much trouble to do this for a rebuild and the fittings and pipe only costs about $30 to change them.

In answer to the other question, I just used the PVC fittings and pipe from Lowes. I could get the ABS from Amazon if I was willing to wait a month. I capped it off with a Valtera fitting on the end since I have been using a Tetford to Valtera adaptor for the last year anyway. I like the Tetford better but am not going to fight the trend. Both seem to work fine.

I did not see A W Warns post first. Maybe I will look it up now and find out why I had such a hard time putting the valves with fittings back in. It was a struggle there for a while to get the front valve in with the gasket in place.

[Al and Missy]

Originally Posted by Bill M.

I just finished replacing my valves and leak checking. I have not put the access hole cover back on yet. I just cannot imagine having enough room to work with the pan hanging down still supported on one side. I know I was straight up under mine a lot of the time and still could only get a few fingers on the screwdriver.

...

I'll admit it was a little challenging to get the screwdriver on the top two screws on the gray valve. Getting the screws back in may be something else altogether. Also I jacked the pan back up to keep critters out until I can finish the job (parts from Amazon day after tomorrow) and the screw holes don't line up. I think I can fix that by levering the pan aft with a 2x4 against the axle. Apparently it isn't unbending the same as it bent.

Oh well......

Al

[GCinSC2]

Al,

While you're in there might as well install a lift kit.

You could be a Hi Slider.

Gary

[A W Warn]

Originally Posted by Al and Missy

Hint - you are already too late.

I need to replace my black tank drain valve. I decided, based on A W Warn's excellent post here, to do both valves and clean out my black tank flush spray head at the same time.

I originally planned to use HF shears and cut an access port in the pan but became afraid to cut blind and also discovered that to access both valves I would have to cut pretty far into the center of the trailer.

So I decided to drop the pan, and then maybe cut an access panel. I have the trailer up on ramps but still can't easily get to the line of bolts at the front of the pan.

So I decided to partially drop the pan. I pulled the bolts on the back, center, and sides and let the front wall bend to drop the rear of the pan. This gives me enough access to do everything I need to and all I have to do is jack up the rear of the pan and replace the bolts I removed.

Does anybody see a problem with this? It was so easy I think I'll not even try to make an access panel.

BTW, I can't believe the scraps of Styrofoam they used to haphazardly shim out the pan on the bottom and sides, just a few good rectangular pieces and a bunch of broken scraps. The wiring in this area is a rat's nest, including the heavy gauge 12V wire for the power stabilizers. I'll clean that up too.

Al

I appreciate your compliment!!

I had difficulty finding the ABS fittings also. In FL there is a business called Mobil Home Depot, probably a branch near you. They carry most of the ABS fittings and pipe. The street el and the combination fitting I got at Camper Corral in Sebring. (I think they closed recently)

Good luck!

[dbj216]

I changed both black and gray dump valves on the Limited several years ago. I did drop the pan to get the job done. I had access to the bolts around the pan on my trailer.

I used PVC piping but I've use ABS piping since. PVC is stronger so I understand.

I used Valterra valves and they have performed well these last 6 years. They are of a simpler design in my view.

David

[JCWDCW]

Others have also noted the mess of scrap Styrofoam in other posts. The Styrofoam is there to cushion the tank from the steel belly pan, not to insulate it....none-the-less replacing it will certainly lengthen the time for the tank to freeze.
JCW

[Al and Missy]

Well, I decided this might be a lot easier, and less bloody, if I dropped the pan. I also realized the I could wiggle in to get access to the front bolts. Previously I was lying on a creeper. Getting rid of that gave me a couple more inches. I jacked up the pan, pulled the front bolts, and lowered the jack. No go - the pan wouldn't drop. After checking for missed bolts (there were none) I finally saw that my axle swap guy (and apparently the factory before him) had mounted the axle with the bracket over the pan flange. No way the pan is coming out without loosening the axle bolts. While I'm tempted to just cut an access port and deal with this problem if I ever have to change a tank, I'm going to see if the axle tech makes house calls. We'll have to get the trailer down off of the ramps, put it up on jack stands, loosen the axle bolts and pull the pan out. While its out I'll cut the flanges away from the axle mounting locations and cut the valve access port.

Details at 11....

Al

[dbj216]

Wow, what a lot more work for you. I had to remove the propane line to get my pan down, but that's duck soup compared to dropping the axle. Not in all cases has Airstream considered easy access to maintenance items.

Yep, get your snippers, nibbler, or cutting torch out and create an easier way to service the dump valves. I probably should have cut an access hatch in my pan when I had it down. I figured I now know how to do it and the second time will be faster than the first. Time will tell.

David

[GCinSC2]

That lift kit is getting closer and closer.

My rig got axles R&R courtesy of AS just after I bought it, long story Al I’ll explain this sept if you wish. But the experienced tech came out from under trailer with his eyes on fire pointing at the mothership and stating we’re gonna bill them extra, that pan is in the way! And a few more things I can’t type.

[crispyboy]

I have done this job and it is easy once you cut a hole in the pan. You will need a piece of galvanized ductwork material to cover the hole. Wear good leather gloves. No real need to drop the pan. I dropped the pan on the previous trailer for a different reason and it was a big hateful job.
The Thetford valves will work easier once you install the rebuild kits and use them a few times.
I would make a recommendation and replace the ABS flange that goes between the tank and the valve. I had both of these go bad (leak) as it is a stress point.
I also installed the Thetford to Valterra conversion kit on the end of the pipe. Just cutoff the old Thetford fitting and glue on the Valterra fitting. Very simple job. The parts were ordered through Out of Doors mart.