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dansawyer · 11-20-2022, 08:06 PM

The RV is a 2002 Nat'l Tracewinds LE - Ca 3126E on a Spartan chassis.

I am not sure if the correct place for this Class A, National, or Spartan. I will start with this forum.

The symptom is: When the compressor finished its charging cycle the secondary tank goes to 125 psi.

A. Sometimes it will stay there indefinitly. That is it will not move for 20 or 30 minutes. (Until I no longer monitor it.)

B. Sometimes it will start to drop and in about 5 minutes drop to 100. This will also drag the primary down and initiate a compressor cycle.

I have just complete a 2 day trim monitoring this. The ration was A. about 40 percent of the time and B. for 60.

I am not sure where to start looking. The secondary runs the front brakes and the air bag suspension. Does anyone have any ideas what could cause this kind of behavior?

(It does not appear to be road surface dependent, however I do suspect the drop occurs more frequentlly on rough or uneven road surfaces. )
Thank you in advance. Please move this if there is a better forum.

Dan

Unplanned Tourist · 11-20-2022, 10:42 PM

Suspension level valve?

dansawyer · 11-21-2022, 01:10 AM

Quote:

Originally Posted by Unplanned Tourist

Suspension level valve?

If that were it would charging up the air and letting it sit stationary be a good test?

Unplanned Tourist · 11-21-2022, 08:46 AM

Quote:

Originally Posted by dansawyer

If that were it would charging up the air and letting it sit stationary be a good test?

That would be a start. But because it's erratic, (comes and goes) you might have to disconnect the link and move the arm up and down. BE VERY CAREFUL YOU DON'T GET CAUGHT UNDER YOUR RIG!

Raising and lowering the suspension might show up a air leak.

dansawyer · 11-21-2022, 09:35 AM

The vehicle sat over night and the secondary did not drop below about 95. That adds to the data supporting a driving / motion / action sensitive leak. In its current position I can test the front arms. It is on a curved 'hill' and access to the front before the front wheels and the back behind the rear wheels is clear. The middle is not accessable. I will check the front suspension for leaks.

jacwjames · 11-21-2022, 10:00 AM

Last year mine started to leak down slowly, then progressively worse, and the irraticcally and at one point it went from 120 psi to 60 psi in 15 minutes. I sprayed down all the fittings on the tanks and found the PPV leaking. But while driving the compressor was able to keep up so I decided to cut my trip short and head home.

First thing I did was build a set of ramp out of 2X10' 30, 36, 42, 48" long screwed together. I made 6 ramps. Put a stop block on the ones for the rear wheel.
Pulled the rig up on the ramps and dropped air. Worked great, could crawl around to check for leaks and sit up near each of the tanks.

Then pulled all the PPV (pressure protection valves) ordered and replaced. Also replace a couple other fittings of similar design and could fail. Bought new Push To Connect fittings also, kept the old for spare. Only spend ~#200 on parts but now no leaks. Rig holds air for weeks.

Unplanned Tourist · 11-21-2022, 10:03 AM

Soapy water in a squirt bottle works great for finding leaks. I use a little dish washing soap, maybe 1 teaspoon in a quart of warm water.

My eyes are better than my hearing when looking for air leaks these days.

Skip426 · 11-21-2022, 10:07 AM

Add the exhaust brake operation and the air horns to the list of items that use air from that tank.

Ray,IN · 11-21-2022, 06:39 PM

FWIW, your air brakes are a separate system from the air springs.
This Spartan compressed air system drawing will help you understand how it works.

dansawyer · 11-22-2022, 05:25 PM

I discovered a Norgren valve had a leak on one of the electrical connections. The valve is symmetrical, an electrical connection on each side. I used zip ties to moderately pull the two electrical connectors together. Thes seemed to seal the leak.

The secondary circuit has been stable for over 6 hours. I will let this go a few more hours to see if it holds

This would answer the static test question. I would presume the front brake circuit and the air bag circuit when not in use are stable.

Thanks for the discussion. I appreciate the input. I am really shooting in the dark here.

dansawyer · 11-24-2022, 07:25 PM

Update:
250 miles later. We started at 8000 feet. We drove 80 miles up and over Hoosier and Vail passes and West on I 70. The secondary cycled about every 4 to 5 minutes for the 125 miles. Then it started holding. This lasted for 30 to 45 minutes until it started dropping again.

We then pulled off an exit for 5 minutes to check an RV spot for the night. Back on the road it started holding again.

It mostly holds when stopped.

I am stuck.

dansawyer · 11-25-2022, 07:21 PM

Update:

Traveled from Fruita CO to Rupert ID today. When we started for the first 80 miles or so until we stopped for fuel the secondary cycled.

After we stopped the secondary stayed at 125 psi for over an hour then it started falling.

The pattern was when we stopped the secondary would stay up in pressure for a significant time and then cycle

This pattern held for the rest of the day.

I will call Spartan Monday to see if they have specific doc on this chassis. The available docs have a close pattern but the specifics are different.