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Topic: Draining air system to replace leaking valve (Read 378 times) previous topic - next topic

Draining air system to replace leaking valve

Stopped in Reno for a few days where I picked up a new pressure protection valve to replace my leaking one. Also either called or visited 7 RV service facilities or truck repair services, and no one is willing to work on my diagnosing air system leaks in my U295 (or even just installing this new one) so it looks like I'm going to be doing it myself.
I have steel safety stands to place next to each of the 8 air bags, but my question is how do I completely empty the air system before I unscrew that valve from the dry tank on one side and the suspension/leveling system on the other? I can open the petcocks on the wet tank and the two dry tanks, but what to do on the other side?
And do I use teflon thread seal tape on the new valve threads, or something else maybe?
1998 U295 36' No slides
Towing 2018 Jeep Wrangler
Previous rigs:
  1995 26' Fleetwood Flair
  1998 34' Fleetwood Bounder
  1997 40' Bluebird BMC
  1999 24' Winnebago Minnie Class C

Re: Draining air system to replace leaking valve

Reply #1 –
Use liquid Teflon not tape. Not sure what you mean by other side? If you drain both dry tanks and the wet tank there would be no other side unless you mean downstream and there would be no air there. The six packs would have pressure to the bags but that would have nothing to do with tank pressure.
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: Draining air system to replace leaking valve

Reply #2 –
Quote from: craneman –
Use liquid Teflon not tape. Not sure what you mean by other side? If you drain both dry tanks and the wet tank there would be no other side unless you mean downstream and there would be no air there.
"Other side" means other side of the valve, so yes, downstream. Why wouldn't there be pressure from the suspension and HWH leveling system on that side?
1998 U295 36' No slides
Towing 2018 Jeep Wrangler
Previous rigs:
  1995 26' Fleetwood Flair
  1998 34' Fleetwood Bounder
  1997 40' Bluebird BMC
  1999 24' Winnebago Minnie Class C

Re: Draining air system to replace leaking valve

Reply #3 –

Raise your coach, put the safety stands in place, use the "DUMP" button on the HWH panel to release air pressure from the air bags.  Coach will sit down on the safety stands.  Open the drain valves on the tanks.  All significant air pressure is now gone from system.  Anything trapped between valves will just be a little poof of air - no worries.

For sealing threads on air system fittings, I recommend either Permatex or Loctite sealant paste:

https://www.oreillyauto.com/detail/c/permatex/chemicals---fluids/glues--adhesives---sealants/pipe-sealer---thread-sealing-tape/58b2d9326850/permatex-high-temperature-thread-sealant/per0/59235

Loctite 2087067 567 Thread Sealant 50 mL Tube, White: Amazon.com: Industrial...

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1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
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