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Topic: Pressure Switch and coach leveling (Read 666 times) previous topic - next topic

Pressure Switch and coach leveling

Ok so I am having an issue on my 03 U320 where the rear end is low every morning.  In a 12 hour period:

LF went up 1.5 inches
RF went down 1.5 inches
RR went down 4 inches
LR went down an inch

Doesn't matter whether I leave the HWH auto level on or off.  BTW my coach does have the Air Tank switch located on the side panel

Anyway I went on my very first "find the air leak" adventure today.  Raised the coach all the way up and put the safety blocks in place.  Went around spraying the outside airlines best I could and found nothing.  Didn't have my coveralls so didn't go under for more fun.  Will do that tomorrow.

What I did find is the Pressure switch (Square D Pumptrol FHG2) was leaking big time right shortly after the raise.  This went on for an hour.  The rate slowed down but still leaked.  I don't' have a gauge between the manifolds (6 packs) and the Check Valve to check the pressure drop.  In one hour I did not see noticeable level changes in the coach. 

Took the desiccants home for a dry out.  they are not pink but hope to get them back in shape.

See Pics - it was pushing out a lot of air in this spot.  So much so I could hear it 20 feet away with the bay door closed. I looked at the diagram and have to believe that one of two things is happening.  The A-port check valve is bad or the B and or C port are pushing air back to the compressor.  The diagram I have shows the A and B lines (Leveling Manifolds and Coach Wet Tank respectively) have a one-way or check valve.  The C port for bladder and Accessories does not.

So I then looked up the square D pressure switch  and from what I saw they should have a pressure relief outlet but mine does not. 

So can I assume that I need a pressure switch ?  New check valve for the B & C lines ?

If I can stop this leaking issue I can then move on to the manifolds and check all that out. 

Let me know if I am heading in the right direction.

thanks

2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC

Re: Pressure Switch and coach leveling

Reply #1 –
Yes, change the pressure switch then go from there with your checking for other leaks.
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: Pressure Switch and coach leveling

Reply #2 –
A few older pics:

Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Pressure Switch and coach leveling

Reply #5 –
Ok I get it that the pressure switch has a leak but where is the pressure coming from.  It cant be from the slide tank at 12 psi leaking for over an hour.  Something has to be putting pressure on the switch.

2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC

Re: Pressure Switch and coach leveling

Reply #6 –
I found that the pressure switches on the 6-packs was leaking on mine.  Spray the 6-packs with soapy water and look for bubbles.

Keith
2003 U320 38' #6197

Re: Pressure Switch and coach leveling

Reply #7 –
Quote from: Charlieboise –
Ok I get it that the pressure switch has a leak but where is the pressure coming from.  It cant be from the slide tank at 12 psi leaking for over an hour.  Something has to be putting pressure on the switch.

Based on your drawing the aux bladder tank.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Pressure Switch and coach leveling

Reply #8 –
Quote from: turbojack –
Based on your drawing the aux bladder tank.


I plan to pump up the Aux tank then check the air flow out of the pressure switch.  I will then dump that tank and if the air flow stops then I have air coming back from A port (manifolds) or B port (Wet tank).  Both of those have one way valves so It could be one or both of those.

Am I thinking the right way here ?
2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC

Re: Pressure Switch and coach leveling

Reply #9 –
Quote from: Charlieboise –
Both of those have one way valves so It could be one or both of those.
Very common for one-way check valves to leak.  If you take one apart you will see it is (usually) a flat metal disc that is lightly spring loaded to seal on a flat rubber gasket.  If only a tiny bit of trash or junk gets trapped between the disc and the sealing surface, the valve will leak.  If the valve is not too old or corroded inside, it is possible to take it apart and clean it out - thus restoring it to proper function.  OR, just save time and effort by simply replacing it.  Your time, your money, your choice.

Part Number Collection

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Pressure Switch and coach leveling

Reply #10 –
Don't quote him or me but Keith Reisch determined my check valves were leaking by airing up the coach then opening the wet tank valve and leaving it that way.  If air pressure gauge on dash is dropping (after several minutes) then check valve(s) is your problem.  He didn't fool with trying to rebuild, he just replaced them.

2000 GV320 4010 build #5712  2019-?
1999 Bounder 2000-2008
Bardstown, KY
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