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Topic: Air Leak from this valve (Read 1200 times) previous topic - next topic

Air Leak from this valve

Greetings Foretravel Owners,

Lately, I've noticed our coach leaks down air pressure rather quickly.
I started the coach to pressurize the tanks then shut down when the pressure reached 110 psi.
I crawled underneath and could clearly hear air escaping and I traced it to this valve that is connected to the driver's side front air tank.

My questions are:
    • What is this valve
    • What is the purpose of this valve
    • Why might air be escaping from the valve
    • Should I replace this valve or is it doing its job

Thanks,
Guy N Christa
2000 U320 4010 WTFE #5609
2017 Ford Explorer toad
Current RVSA Certified RV Technician
Previous 2001 Forest River Windsong 340

Re: Air Leak from this valve

Reply #1 –
That looks to be the pressure regulator for the air suspension. It has a diaphragm in it that will leak. Yes you can and should change it. There should be a tag on it to identify it by. You should be able to use that part # to order it by, or heavy truck parts place may have them.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Air Leak from this valve

Reply #2 –
 The Pressure Protection Valve.

There is one on the Front tank, and One on the Rear tank.  The purpose of this valve is to retain a minimum quantity of air in the tank, in the event of a catastrophic air loss downstream of the valve.  If the Front and Rear air tanks were only used to operate the brake system, this valve would not be necessary.  However, on our coaches, these tanks are "multi-purpose".  They not only provide air pressure to the brake system, but also to the suspension system, the throttle/cruise control (on some models), the air step/cover, etc.  If a hose were to be cut...say to one of the air bags, then the pressure in the respective air tank could be rapidly depleted.  A properly functioning Protection Valve would close, retaining enough pressure in the tank (usually about 65 psi) to operate the brakes and bring the coach to a safe stop.

Part linked below is a good replacement.  You want a valve that closes at about 65 psi:

90555396 - Pressure Protection Valve - Haldex product

Pressure Protection Valve, 90555396, Haldex
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: Air Leak from this valve

Reply #3 –
Guy, please make sure that your coach is properly supported before crawling under. Especially if you're looking for air leaks.
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Air Leak from this valve

Reply #4 –
Quote from: folivier –
Guy, please make sure that your coach is properly supported before crawling under. Especially if you're looking for air leaks.
I left that detail out, but I did block the coach up before descending below.
2000 U320 4010 WTFE #5609
2017 Ford Explorer toad
Current RVSA Certified RV Technician
Previous 2001 Forest River Windsong 340

Re: Air Leak from this valve

Reply #5 –
We had the same problem a while back, here is what the diaphragm looks like inside.
What did you do to your coach today VI

Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Air Leak from this valve

Reply #7 –
Quote from: GuynChrista –
Wow, where did you get the rebuild kits?

We had a couple left from when you could get them. Now it is just cheaper to replace the valve with new. You don't have labor time to disassemble, clean, and put back together.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Air Leak from this valve

Reply #9 –
Quote from: DavidS –
Used these.. Replaced a couple about 3 yrs and still going strong
David,

I have seen where you recommended this valve several times in other threads.  Do you know for sure what the closing pressure is for this valve?  It says nothing about that in the eBay ad.  Is it marked somewhere on the valve?
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: Air Leak from this valve

Reply #10 –
I cant remember exactly but I want to say 55 to 65?

Other numbers on the valve do not go to anything I could find online

Pretty sure I had found it at one time and it fit the perimeters

Re: Air Leak from this valve

Reply #11 –
I used these, 65 psi.
(2 Pcs ) Haldex 90555399 Pressure Protection Valve 1/4" NPT , 65 PSI NEW | eBay

Genuine Haldex. Ad says New rather than New Other.  Time and effort to replace these is significant.  I would hate to save a couple bucks and then have to do them over. But then it could go the other way as well.  Original ones lasted 18 years.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Air Leak from this valve

Reply #12 –
As I agree with Roger.. Hate doing things twice.. Mine are holding up fine.. Might turn into a victron/ ? Argument and then again maybe not.. I only know what has worked for me as others so it might be another way of skinnin the proverbial cat

Re: Air Leak from this valve

Reply #13 –
Both leak, one started blowing air out the hole in the bottom all the time. With no air in the tank I cleaned the bottom and sides of the PPV with alcohol and put a band-aid made of 3M VHB tape, put a zip tie around the cylindrical part and another over the end and across the top.  That leak is almost nothing now.  The valve still leaks, a project for next week.  I have new check valves too,  when I take it apart I will replace anything mechanical that could fail over time.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN