Skip to main content ↑ ↓
Topic: Another air leak this time at rear six pack pressure switch (Read 1007 times) previous topic - next topic

Another air leak this time at rear six pack pressure switch

I found another air leak this time it is coming from the pressure switch on the rear six pack.  It is leaking from the little Allen head screw on pressure switch (see photos).  Tried a little thread sealant on the threads but still leaks.  Checked to see what they are new and Foretravel wants $160 bucks for it.  Didn't know it was a solid gold sensor.  Anyways, do you'all think I could put a little bit of silicone on the threads to seal up the leak or will that damage the switch, or am I just trying to prolong the inevitable and need to just replace the switch?  Just to put a fly in the pudding, I found this quote from another forum
 "ok, i have this figured out and understand it now mostly. I talked to HWH today. that pressure switch on the rear 6 pack is a low pressure switch for the system pressure, not the airbags. it is normally closed and opens at 85 psi. when it is closed below 85psi it will turn off the travel light on the hwh panel.
Newell says that almost all of the coaches have it plugged and disconnected. with it disconnected, the system will ALWAYS think it is above 85psi."

What do you think just cap it and unplug and let computer think it has 85 psi or is this asking for trouble down the road? 
2002 36' U270 Foretravel

Re: Another air leak this time at rear six pack pressure switch

Reply #1 –
I would drain air, remove and clean the allen and use Rectroseal #5 on the threads.  If any thread damage (likely as dissimilar metals), replace the plug.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Another air leak this time at rear six pack pressure switch

Reply #2 –
Already tried using Permatex 59214 High Temperature Thread Sealant as well as some other plumbing sealant whose name I've forgotten. They didn't work.  That's why I was wondering about silicon.  I don't know if that will damage switch or adjust the opening pressure of the switch.
2002 36' U270 Foretravel

Re: Another air leak this time at rear six pack pressure switch

Reply #3 –
Is the plug bottoming out? If not and the threads are tapered. Carefully wrap teflon tape about and 1/8" off the bottom of the threads to give it more girth.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Another air leak this time at rear six pack pressure switch

Reply #4 –
Buy the switch. If you bypass the low air pressure warning and you lose your air cruising down the highway you won't know it until the rear brakes come on.
That low air pressure warning may give you enough time to pick a better place to park.
That switch turns on the travel light when it sees 85 psi or more OR the low air pressure warning when it sees less than 85 psi.
And you will never know if the green travel light is authentic or on with low air pressure that might not be enough to lift the coach to travel height.
John Duld
1995 U320C SE 40'

Re: Another air leak this time at rear six pack pressure switch

Reply #5 –
Quote from: John Duld –
Buy the switch. If you bypass the low air pressure warning and you lose your air cruising down the highway you won't know it until the rear brakes come on.
That low air pressure warning may give you enough time to pick a better place to park.
That switch turns on the travel light when it sees 85 psi or more OR the low air pressure warning when it sees less than 85 psi.
John, the pressure switch does turn on the travel light when it is above 85 psi, but I would have thought the low pressure warning would come from the actual senders from the tanks, otherwise the warning would only be given for the rear tank and not the front tank as the rear six pack is feed by the rear air tank and the aux compressor and the front six pack by the front air tank and the aux compressor.  The front and rear systems are kept separate by multiple check valves.
2002 36' U270 Foretravel

Re: Another air leak this time at rear six pack pressure switch

Reply #6 –
Quote from: craneman –
Is the plug bottoming out? If not and the threads are tapered. Carefully wrap teflon tape about and 1/8" off the bottom of the threads to give it more girth.
Craneman, the plug does not bottom out.  When I first started messing with it to see if I could stop the leak, I was able to turn it 4 or 5 revolutions past the flush position it was at originally.  The more I think about it the more I think it is just a plug and has no effect on the adjustment.  I think I could silicon it with rtv gasket material for now, but I think it would just be a temporary measure as something is probably going bad internally allowing air to leak out the hole and past the plug.  Would try the teflon tape but this plug is incredibly small.
2002 36' U270 Foretravel

Re: Another air leak this time at rear six pack pressure switch

Reply #7 –
Morning Jbeem,
You brought up a good point about the low air alarm.
The way I see this is two separate systems
The coach air brake system and the HWH air suspension system. Which is charged by the air brake system.
I don't think the 85 psi switch turns anything on or off I think it tells the HWH computer what it sees and if it's less than 85 the computer turns on the red low air pressure light to warn that pressure may not be sufficient to maintain travel height.
If it sees more than 85 the computer will give you the travel system.
I did forget about the air brake low pressure warning ( not sure but maybe 60 psi? ) and you would get that before the parking brakes.
If you removed the 85 psi switch to force the computer to see more than 85 psi all the time  I would still take a walk around to confirm all four corners have come up to travel height. The green travel light just tells us power has been sent to the travel solenoids but no information if they opened.
You would loose the ability of the computer to remove power from the travel solenoids to trap airbag air at travel height if air pressure went below 85 psi. And the first heads up of the low air red warning would be missing.
Probably none of this would be much of an issue but I would still replace the switch and keep the system set up as original.
Any opinions or comments are welcome.
John
John Duld
1995 U320C SE 40'

Re: Another air leak this time at rear six pack pressure switch

Reply #8 –
Quote from: jbeem –
Foretravel wants $160 bucks for it.  Didn't know it was a solid gold sensor. 

It's a Nason pressure sensor switch. Most of the numbers appear in your picture. Take the numbers and shop the price on Ebay or somewhere.  The ones I see are in the $40.00 - $100.00 range.

Re: Another air leak this time at rear six pack pressure switch

Reply #9 –
If you want to replace the 85 psi HWH pressure switch, post linked below gives some part numbers that will work (less $$ than at FOT):

6 pack rebuild
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: Another air leak this time at rear six pack pressure switch

Reply #10 –
Went ahead and called HWH and ordered the part from them $126 and installed today.  Thanks for advice.
2002 36' U270 Foretravel