air leak, what is this?

David Anderson · December 31, 2018, 09:11:41 AM

This valve is leaking below the cap knob. It has a tie wire on it to keep it locked from turning. It is on the front air tank between my front wheels and has two read plastic lines on it, I assume to the front wheel service brakes. Is this some sort of regulator for the front wheel brakes??

David Anderson · December 31, 2018, 10:54:49 AM

Ok, I called a parts guy at San Antonio Brake and Clutch and texted him the picture and he called it a PR-2 valve, but there are multiple types. It is an overpressure preventer factory set at 65psi. I don't know if that is the cracking pressure or the pop off pressure. Anyone know the setting for this for an Eagle 10 brake system? Clifford??

Lee Bradley · December 31, 2018, 11:00:03 AM

Supplies low pressure air to you wipers, air seat, etc.

David Anderson · December 31, 2018, 12:53:31 PM

Yes it is off the aux tank. Apparently the two red lines from the front are together at a tee on the valve and come from the main brake tank. That would be the inlet. The aux tank would therefore be regulated by the PR2 valve. Anyone know what the pressure should be?

DoubleEagle · December 31, 2018, 02:09:21 PM

60 or 65 psi would be fine. It's the appropriate pressure for an air seat or the doors (which close like the jaws of death at 120 psi).

buswarrior · December 31, 2018, 03:18:15 PM

Hmmm... the devices are typically regulated, not the tank?

I'm not an eagle guy...

Regulating the whole tank down, reduces the volume of air available to do work, vs tank at system pressure and regulating the supply of air to the devices.

Anyhoo... check what's at each end of those hoses...

Happy coaching!
Buswarrior

Dave5Cs · December 31, 2018, 03:40:32 PM

Airbag filter with 65PSI (PPV)pressure reg on it then from accessories tank.

https://www.anythingtruck.com/product/060-282811N.html

David Anderson · December 31, 2018, 05:38:08 PM

The valve doesn't crack open until 65psi. After that the tank fills to 120psi. Therefore, the valve the guy at SA Brake will work. I'll have to go get it Wednesday.

buswarrior · December 31, 2018, 06:55:02 PM

Ok, given my head a shake...

From the discussion so far, that pressure protection valve's job is to focus air pressure on the brake related tanks, under a catastrophic air leak. If the pressure is below 65 lbs, no air flows to the auxiliary, the entire effort of the compressor goes only to the brake tanks.

Be sure it is set correctly, winding the cap changes the setting. When something goes wrong, it's proper function means everything...

Happy coaching!
Buswarrior

Bob Gilbert · December 31, 2018, 07:12:04 PM

David, that's a pressure regulator set at a given pressure probably 60-65lb, had the one at the back that controlles engine stop etc fail a couple years ago in so Tx, bought a regulator at HF still there 20,000 mi later. Bob

buswarrior · January 01, 2019, 06:53:17 AM

Not a regulator, a protection valve.

Nothing flows until it gets to the set point, then it allows full flow to system pressure.

Closes again, if pressure falls below set point.

Like a dam, no water goes over the top, until full, no water over the top, if the resevoir level drops.

Happy coaching!
Buswarrior

David Anderson · January 01, 2019, 09:05:51 AM

Quote from: buswarrior on January 01, 2019, 06:53:17 AM
Not a regulator, a protection valve.

Nothing flows until it gets to the set point, then it allows full flow to system pressure.

Closes again, if pressure falls below set point.

Like a dam, no water goes over the top, until full, no water over the top, if the reservoir level drops.

Happy coaching!
Buswarrior

You have it correct. I hope to get a new one Wednesday. The only device on the coach that I use the aux tank for in my air horn. All other air devices are gone, ie. the air door and wipers.
The factory setting at 65psi will work for this application.

I have to get it fixed because it leaks from the supply side and my whole system leaks down in about 10 minutes.

David