Interstate Mods - I'll go First

[Protagonist]

Originally Posted by InterBlog

This issue has come up on older threads, but one of our biggest driving risk factors in the deep south is concrete blow-outs (to use TxDOT's somewhat contentious term), which can develop very rapidly when the concrete simply shatters and collapses into a R.O.W. abyss (they are like potholes on steroids).

The engineering term is "spalling." The most common cause is freeze/thaw cycles in most of the country but in the southern states it's caused by rusting of the rebar; iron oxide is larger molecule than iron so rust causes the steel rebar to swell. Except that when it's encased in concrete there's no room for it to swell. So the concrete fractures to make room.

[DavisBurns]

The original post did not make it clear the additional lights were only used when there was no other traffic. In fact there was a comment that you could blind an oncoming driver who didn't dim their lights. Maybe that was a warning NOT to use them when there was other traffic but that wasn't clear.

Can I just add that some people want their campsites to be dark because they like the night sky so keeping lights low or off after setup is a courtesy to other campers. Many of us don't enjoy the "festive" party lights hung on awnings and other attempts to light up the night. Of course, it's a rare rv park that isn't overlit to begin with.

[73shark]

Originally Posted by Protagonist

The engineering term is "spalling." The most common cause is freeze/thaw cycles in most of the country but in the southern states it's caused by rusting of the rebar; iron oxide is larger molecule than iron so rust causes the steel rebar to swell. Except that when it's encased in concrete there's no room for it to swell. So the concrete fractures to make room.

I'll bet that's why most new highway construction using concrete and rebar uses epoxy coated rebar.

[gmillerok1]

And now for something completely different... .

A modification I did this weekend is probably the least glamorous and most useful I've done so far.

I modified the sewer connection to the macerator so I can use a twist off connector as the attachment shows.

Why? A bit of history may help explain the reason.

I have to keep my van outside all year. The first year winter season, I winterized the van by using antifreeze, including the waste tanks, until pink ran out the hose. Or more like pink frothy stuff because it never would turn red like it would from the faucet. I figured that was good enough. And the first year, which was mild, it was.

The second year, no so much. After a hard freeze, and thaw, I noticed liquid slowly leaking from the macerator. Why? Because even though I had attempted to empty the tanks and then use antifreeze, the much harsher winter caused it to freeze. Or, perhaps, the seal was damaged. No matter, it had to be replaced. Airstream would replace it under warranty, they said, if it was not related to freeze damage, which of course, it was, because of the poor design of the sewer system itself.

When I unhooked the sewer hose, I was astonished to see how much liquid came pouring out-at least 3 or more gallons. My guess, is the plumbing can hold maybe 5 gallons or more. Why? Because Airstream put the pump level with the sewer pipe so it won't be able to pump the liquid after the pipe is about half empty-it can't pump air. It just sits there and makes a nice froth instead. To winterize it would probably take 20 gallons of antifreeze, if it could be done at all, depending on how much protection is needed.

So, I was left with the unpleasant prospect of unhooking the 12" black sewer hose to winterize it every year. And that's a pain to do.

So, I replaced the 3" black hose with one of these:

Fernco. PQT-300 3 in. Flex Quick Tee - - Amazon.com

(Lowe's carries it as well), and one of these:

Amazon.com: Valterra Products, Inc. T1020-VP 3" Black Carded Termination Cap with Bayonet Hook: Automotive

That also gave me an option to use a standard gravity type twist on hose if I want to stay awhile at one location rather than dump every day. Or if the macerator fails as a backup.

The modification was not too difficult. But you will need about a 2.5" pieice of 3" hose. I found a local supplier that sells Kanaflex 300 EPDM and a couple of clamps. The pipe that comes from the tank has a rather interesting Airstream made adapter that reduces the pipe from a 3" ID ABS (outside 3.5") for a 3" ID flexible hose that the 3" sewer hose is connected. I could find no similar adapter, so I suppose that's why the make it up in the shop. This is connected with a standard 3" ID coupling to the 3" abs pipe to the valve. You remove the adapter, toss the coupling, and put the adapter on the other side of the quick-t adapter, stick about a 2.5" length of 3" Kannaflex 300 EPDM on it, and then stick it on the macerator. The other end of the flexible-t goes directly into the 3" abs pipe from the valve.

The cap just twists on.

Now, I can use the macerator, and when I return from a trip, remove the cap to drain any remaining fluid out. I can't imagine that it can be good for the macerator to have standing water sitting there all the time.

And if you don't believe me, unhook the hose from the macerator, and stand back!

[ben322]

Nice mod! I thought about a schedule 40 sanitary T with two rubber couplers but thought it might be too stiff. That setup looks like it retains a lot of flex.

[gmillerok1]

Thanks! Using a rigid abs t was my first choice, but it was not possible to do without hacking off several inches of the 3" abs pipe from the valve, or permanently gluing it on, and I don't like doing things I can't undo in case it doesn't work out.

The Flexible-t is an almost perfect fit. Even though it is longer than the stock 3" black flex pipe AS used, there is no adapter on the valve side or the macerator side besides the homemade one AS made, so you gain about 3" back by doing away with it. The down side to the flex adapter is that I wanted to put a twist on shut off valve on the t, but was concerned the flexing could be a problem with it attached to the t bouncing down the road.

The flex pipe is very stable and fits nicely in place of the standard 3" hose.

On thing I forgot to mention. If anyone removes the hose from the macerator, it does NOT go back snug as far as you can push it on. There is a small, raised area that will keep it from being tight if you push it on too far, and it will leak. The trick is to back it off so the hose is just on the smooth round part on the end, and no farther.

[Titus]

I was concerned about the mild colored frothy discharge after my first winterizing but I too musta got lucky after my first (mild) winter. I'll not take that chance in winter #2. Maybe your post will make more sense after crawling underneath, but I don't understand what the Valtera cap screws on to. Is there a fitting that goes into the new rubber T that you installed, and this cap goes on that fitting? All of this stuff goes immediately upstream of the macerator - correct? Thanks

[Boxster1971]

Great mod G! Thanks for sharing. This one is going on my to-do list.


- - Mike
2013 Interstate Lounge EXT on 2012 Sprinter

[gmillerok1]

The Valtera cap (or the sewer hose) screws into a coupler such as the one described here:

Amazon.com: Valterra T1029-1 Termination Adapter with 3" Bayonet x 3" Spigot: Automotive

This adapter is connected to the Flex-T with a clamp.

I forgot that part. Sorry for the confusion. And yes, it all goes upstream from the macerator. Basically, you are removing the following:

3" to 3" coupler
3" to 3" hose adapter
3" hose

and taking the 3" to 3" hose adapter and tossing the rest, and then it goes:

3" ABS pipe from the valve to the 3" Flex-T (inserted over the end of the 3" ABS pipe).

The saved 3" to 3" hose adapter then goes on the other end of the Flex-T with the smaller end for the 3" hose with a clamp, and then a short piece of 3" hose connects to the macerator with a clamp.

You put the Valterra T1029-1 Termination Adapter with 3" Bayonet x 3" Spigot on the other opening of the Flex-T and the cap on that.

It's easy to see once you take a look under the van. The only thing not easy to see is the 3" to 3" hose adapter. It's clamped on to a 3" coupler that is then connected to the 3" ABS pipe on the other so the flexible hose can be connected to the macerator at the factory. Since you are using the Flex-T in the place of the hose, this adapter has to go on the other side so you can connect the 3" hose to the macerator.

Hope that helps.

Originally Posted by Titus

I was concerned about the mild colored frothy discharge after my first winterizing but I too musta got lucky after my first (mild) winter. I'll not take that chance in winter #2. Maybe your post will make more sense after crawling underneath, but I don't understand what the Valtera cap screws on to. Is there a fitting that goes into the new rubber T that you installed, and this cap goes on that fitting? All of this stuff goes immediately upstream of the macerator - correct? Thanks

[73shark]

Were you able to do this w/o raising the AI off the ground?

[gmillerok1]

I used these on the streetside rear wheels to raise the vehicle:

http://www.amazon.com/gp/product/B00...ilpage_o03_s00

Originally Posted by 73shark

Were you able to do this w/o raising the AI off the ground?

[InterBlog]

Originally Posted by 73shark

I'll bet that's why most new highway construction using concrete and rebar uses epoxy coated rebar.

In some areas, spalling may be caused by a corrosion issue. Hereabouts, it is most often caused by road base that was installed in a faulty manner to start with. It's the age-old problem of erosion beneath the concrete surface because they never bothered to install proper drainage. Water works its way down through the slab joints, scours out the underlying soil, and then the weight of the vehicles crushes the overlying mass. The rebar usually remains in quite good shape as it ends up in a tangled bird's nest at the bottom of the hole. Good rebar structural integrity has a lot to do with why it is so effective at ripping tires clean off rims.

[Teamaron]

Originally Posted by Protagonist

Be careful of your clearance vis-a-vis the generator. It's already very close to the stock sway bar, so a larger-diameter bar could chafe the generator cover.

Well,

Installed the new Hellwig sway bar. Ride is exceptionally improved.

But protag you were correct. It is up against rear of generator. Not sure how much and if there is movement against it.

I will be keeping a close eye on it.


Sent from my iPhone using Airstream Forums

[InterBlog]

Originally Posted by Teamaron

Well,

Installed the new Hellwig sway bar. Ride is exceptionally improved.

But protag you were correct. It is up against rear of generator. Not sure how much and if there is movement against it.

I will be keeping a close eye on it.

Sent from my iPhone using Airstream Forums

My husband notes that this is only an issue on the newer Interstate models, if anyone was wondering. There is no potential interference imposed by the upgraded sway bar on the generator in the case of our T1N-based Interstate.

I do agree with the phrase "exceptionally improved". My only regret is not knowing about this issue sooner.

[Teamaron]

I drove it again today on I-95.

Nite and Day.

Why did I wait a year? Why doesn't Airstream do this mod?

One may never know.....


Sent from my iPhone using Airstream Forums

[73shark]

Originally Posted by Teamaron

Well,

Installed the new Hellwig sway bar. Ride is exceptionally improved.


Sent from my iPhone using Airstream Forums

While I can understand how a sway bar improves handling, not sure how it can improve ride quality.

[InterBlog]

Originally Posted by Teamaron

I drove it again today on I-95.

Nite and Day.

Why did I wait a year? Why doesn't Airstream do this mod?

One may never know.....

Sent from my iPhone using Airstream Forums

Why doesn't Airstream do this mod? When I asked my husband this same question yesterday, he started uttering expletives. I think the short answer is that Airstream doesn't do many of the things that it arguably should do in the name of basic business integrity. In creating the Interstate, Airstream fundamentally changed the dynamics of the Sprinter, but it opted not to make the corresponding stability modifications called for by its own design. And the rest is history, which involves a lot of unnecessary stress in driving, at least until one discovers the mod that should have been done to start with.

[Teamaron]

Originally Posted by 73shark

While I can understand how a sway bar improves handling, not sure how it can improve ride quality.

Handling / Ride

Ride / Handling

Tomato / TomAto

I meant same thing

It just Drives better.........


Sent from my iPhone using Airstream Forums

[73shark]

I figured you, if anyone here, would know the difference.

The sway bar can have a negative effect on ride tho since it couples what one side does to the other. On a rig this size I'm guessing that would be minimal when compared to a small car.

[unifreck]

With the heavier sway bar, Koni shocks (ala Sprinter Store), Sumo springs spacers front and rear; my 9 foot tall Sprinter drives more like a sports car. It tracks and corners very well and wind does not make it feel like an uncontrollable slab. All the difference in the world of handling safety.