Pressure Protective Valve "PPV"

[Retiredwarhorses]

After getting the new M931A2 and having a lousy 30.00 part cause so many issues...I took apart the old one, here are the pics.
If they had used a stainless steel needle it may have prevented the unit from not working.
this truck had only 4 hrs on it, everything new...this is what not draining the air tanks gets you I suspect.

Issues I had were, air tanks going to 150psi and venting out of dryer, no horn, wiper motor etc...I would have sworn the issue was the Governor...but Suprman stayed the course and convinced me to gittr dun....15min Job.

 

[crasheej]

Clean up, put back together good to go now?

 

[ichudov]

Awesome job and great pictures? Where is that valve located exactly?

 

[Retiredwarhorses]

NO, the valve was replaced...no cleanup, the needle and entire assy was frozen up and the rust was severe.

the Valave is located on the Inlet of the Wet Tank....

 

[aspann]

Where did you get your PPV valve? Is it the same as the one on the primary tank?

 

[doghead]

http://www.steelsoldiers.com/showthread.php?100355-Air-system-relief-valve-opening-on-M925-Frozen-air-lines-valves

btw, the new site google search works great!

 

[Retiredwarhorses]

Where did you get your PPV valve? Is it the same as the one on the primary tank?

Napa, part was in the parts cross reference located in 5ton forum....
Its a standard 65-75 psi ppv....28.00

 

[Purplerambler69]

I recently had to replace my ppv. My local Napa wasn't able to help me even with the part numbers from this sites cross reference page (no big surprise). I then went to my local Mack garage. The ppv I bought there was built slightly different than the one I removed from the truck but with 1 quarter inch 90 degree elbow, it connected fine and worked perfectly. This ppv was from Meritor Wabco with part # R95590555396. I also purchased an air dryer service kit which had the exact same parts as the originals. This was a Haldex part # DQ6026. Just thought I would add this in case someone out there dosnt have a Napa close-by or prefers not to deal with them.

 

[juanprado]

The OE valve is made by Bendix and is adjustable by turning the knob/cap. No reason for us to adjust it and I think the design is one of the reasons it builds up crud. It is available at Napa rebuilt in the Haldex line with an x at the end of the part number signifying rebuilt. The part number is here on a previous thread I posted the info on a m939 thread. (don't have it handy as I am on a phone)

Haldex and others also sells a pressure protection valve with the same pressure rating and ports but is a sealed one piece external design made in plastic/nylon or cast that is superior. Does not look the same but does the same exact thing and might be better suited to keep moisture out of it.

 

[Floridianson]

http://www.vanhorntruckparts.com/product/20777/PR-2-Pressure-Protection-Valve/ I got mine from them $34.78 shipped.

 

[Kawgomoo]

On my truck the valve was no good either. When i crawled under their to check it out i noticed the lock wire and inspection tag were missing. The adjuster was cranked all the way in.

I removed the valve, cleaned it up, and reinstalled it. At first it was not working {i put it back together the same setting i found it} As the truck was airing up passing 80psi i turned the wipers on and crawled under the truck. Backed the adjustor on the ppv out about a turn at a time until the wipers came on. I will do a pressure drop test to see when it cuts out tomorrow, and finalize the adjustment.

All in all. Repair cost zero dollars. I have every confidence it will work fine, until it gets full of crap again.

Dirty


Clean Enough