Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 12, 2025 ...

Travel Mode Air Problem

October 12, 2016, 11:10:15 am

I cranked up the coach to take to the lake for the week while I sailed in a regatta. Initially I thought the lean to the right might have been the crown in the road but after stopping to hook up the toad found the air bag deflated and the tire rubbing on the bottom of the coach in the passenger side rear wheel well. The coach would level and stay level when I put in Level Mode.
I went back to the house and started  researching.

Theory, Discussion, and Initial Observations
(Part One of this topic)

I felt the problem was the in the Leveling valve and started reading there.

Theory (as I understand it)
The valve (90555105) has an input port (top) from the brake tank, two output ports (one capped off)  one of which  goes to the appropriate Travel port on a sixpack manifold, and an Exhaust port (bottom).

As the load on the suspension pushes down, the valve allows air from the air tank to flow through it to the Travel port and into the appropriate air bags.

As the load decreases, air from the bags flows back through the Travel port through the valve and out the exhaust port.

The air does go through the 6-pack but my initial thought is that that solenoid has to be OK.

Discussion
I took a picture of the ride height assemblage on the rear right (attached). Note that there is a bright relatively clean section of the vertical riser at the top. The horizontal rod is only slightly down .

I took a look at the left rear. The horizontal rod was pointing downward and the length of the vertical rod was shorter than that on the right.
(on concrete drive with slope from front to back but level across)

I loosened the right rear vertical rod holder and pushed it in until the measurements on both sides were roughly the same.

After starting the engine and airing up the coach again would level but whee I turned level off would settle onto the right rear tire. Relatively quickly.

I have inspected the exhaust ports on the level valve and, while they have lost their boots, look clear.

I have the coach on the support tubes and with the level mode on the bags are full.
I haven't dissembled  the control rods and I guess that is the next step. At least to get to the place where I can manually rotate the valve.


Observations
1) I am assuming that the valve on the right side of the coach is controlling the air bags on the right side.......
I ask this because the control rod on the right looks in neutral and the on of the left is pointed down.

2) The diagrams associated with the level valve make it appear that when the control rod  rotates upward the valve goes into inflate mode and correspondingly a downward motion exhausts air. (Up wants more, Down wants less)
HOWEVER
My instructions also talk about valve facing toward the front of the coach. If I turn the value around to face the rear, the directions change and now Down wants more, Up wants less)  **I think**

I have a new leveling valve coming in today but would still like to find that I just haven't adjusted things correctly.
Any incites?

More to come in Part Two.

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Re: Travel Mode Air Problem

Reply #1 – October 12, 2016, 11:46:37 am

I am going to say leveling adjuster is bad.  I have had to replace a few over the years.

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Re: Travel Mode Air Problem

Reply #2 – October 12, 2016, 11:58:27 am

Elliot,

I am no expert on ride height systems, but maybe this PDF can help you as you reason through things.

http://www.heightcontrolvalve.com/docs/Haldex/EGP-HCV-Product-Information.pdf

Look at page 2, Figure 2.  The top two diagrams show what would be the ride height valves as installed on the left and right side of our coaches.

In those two drawings item #3 is the rubber boot on the bottom of the valves.

The drawing shows that regardless if the metal rod is coming off the right side, or the left side, moving the rod to the Up position is +, and moving the rod to the down position is -

It would appear that this indicates that the rod pushing up would increase ride height, while pulling down would decrease ride height.

Again, I am not an expert on these systems, but thought this might help you out as you reason through it.

Chris

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Re: Travel Mode Air Problem

Reply #3 – October 12, 2016, 01:04:17 pm

Elliott
When you turn level off are you talking about the level system or the travel system? And where does the air exit?
The dump solenoid or the ride height control valve?

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Re: Travel Mode Air Problem

Reply #4 – October 14, 2016, 04:05:16 pm

Part Two:  The aftermath

Thanks to Barry and a couple of others for verifying my diagnosis that the Leveling valve was probably my problem.
I ordered a new one  (90555105) and after about a week it arrived. I have another brand but wanted a "plug compatible" one for my first attempt.
 Those of you who know how tiny I am can appreciate the struggles I had to get in the small start battery hatch to unbolt the valve.
Finally toward the end I figured out how to get both arms inside at the same time.

Bolting it all back together was a relative breeze.
I aired the coach up and moved it back and forth in the driveway. I'll take her out for a spin a little later to see how the valve reacts but it all looks good.

Lessons learned/Recommendations for next time.
 I would recommend that you get new fitting when you get the valve.
 
  I was going to reuse the air line fittings  but wanted to replace the two elbows - 1/4 NTP to 3/8 airline, and one 1/4 NTP
  plug on the valve.
  I was unable to locate the elbows in about 3 hours searching around Georgetown.
  I wound up reusing the old elbows but could not extract the plug, even using a 24 mm wrench and a small impact driver.

I may construct a vise mount to plug into the hitch.

It was great fun but I think I'll try to get my kicks some other way.

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Re: Travel Mode Air Problem

Reply #5 – October 14, 2016, 06:57:24 pm

If this is the same fitting on my coach, I believe it's a Parker P/N: VS269NTA-6-4 (or equivalent of another manufacture)
These are specifically made for DOT Nylon Tube Air brake lines - thus the NTA in the part number.
-6 is the tube size in 1/16th of an inch, so 3/8" OD on the air brake line (that's what's on my coach)
-4 is the thread size in 1/16th of an inch, so 1/4" NPT that threads into the ride height valve.
The tubing and fitting should be marked DOT so you can tell they are compliant with that standard and thus compatible.

What makes these special is a metal tube that exactly inserts inside the nylon air brake tube (0.245").  A similar looking fitting bought in the plumbing section of a home store will have a smaller (.218") metal tube that might not seal well.  Fittings without an insert at all are made for copper tubing.

Here's the Parker catalog.  On page E4 there are instructions for tightening: http://www.parker.com/literature/Brass%20Products/3501E-E.pdf

There are Parker stores around the country (a good search term is "fluid power"), Amazon and other online stores.  I would guess truck service centers would carry these as well.  I'm not affiliated with Parker but I do specify many of their components at my work where we build locomotives.  They are known for quality stuff.

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Re: Travel Mode Air Problem

Reply #6 – October 14, 2016, 07:44:45 pm

The problem I had changing my air bags was the factory fittings had the sleeve in the tubing and the new fittings have the sleeve built in the elbow or straight fitting. I had to cut the air line to remove the sleeve and ferrule to go to the new fitting. Luckily there was some slack to do so.

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