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 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
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.
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 (https://www.haldex.com/en/na/valves-9c82abc0/pressure-protection-valves/haldex-pressure-protection-valves/90555396/)
Pressure Protection Valve, 90555396, Haldex (https://www.ryderfleetproducts.com/haldex-90555396/pressure-protection-valve-p-u55-90555396)
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.
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 (https://www.foreforums.com/index.php?topic=30072.msg291501#msg291501)
Pamela & Mike
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
PRESSURE PROTECTION VALVE - 1/4" NPT - REPLACES 9054107 842234136687 | eBay (https://www.ebay.com/itm/PRESSURE-PROTECTION-VALVE-1-4-NPT-REPLACES-9054107/254064851854?hash=item3b2771fb8e:g:weAAAOSwQS1aN-iX)
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?
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
I used these, 65 psi.
(2 Pcs ) Haldex 90555399 Pressure Protection Valve 1/4" NPT , 65 PSI NEW | eBay (https://www.ebay.com/itm/2-Pcs-Haldex-90555399-Pressure-Protection-Valve-1-4-NPT-65-PSI-NEW/162157994961?epid=1542116077&hash=item25c15ea3d1:g:tFIAAOSwyLlXorRe)
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.
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
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.