Wanna See A Leak?

[tdelorme]

I knew I had a leak somewhere because my auxillary compressor kicks on about every three hours. This evening I had some time so I started searching for the leak. First spot I checked was the steering compartment where there are so many air connections, and proving the old saying that even a blind squirrel finds a nut now and then, there it was. Looks like the Norgren valve has a small crack. Does anyone have the NAPA replacement part number for these valves? I think I will go ahead and replace all the easy ones.

[Jon Wehrenberg]

Ted,

From Prevost, part number 641274 cost $55.79 each.

Now I will confuse you. Before you start replacing things check a few other places. Typically when the coach is parked there is no aux air pressure on these valves. The valve my have been used to hold air pressure in the air bags, in which case the symptom may be a coach that leans or settles down.

But unless your converter has set up the leveling system such that aux air pressure is required to maintain a given pressure to hold a valve like this open you should not see this unless your bus has the leans, in which case you will still have an aux system leak.

This can be quickly checked by feeling the solenoid valves in the steer compartment, key off, and if one or more is warm then it could be aux air escaping from around the O ring on the actuating plunger. I'm not sure any of us here can give anyone else a definitive answer on leveling and suspension system valve problems because of the complexity and variations in the generations of systems designs used on our coaches. Those variations were due to design changes by both Prevost and by converter changes to provide features not on the Prevost system.

If you share some of the information about how your bus has been acting we might be able to be more helpful. The picture below shows the valves to check to see if they are warm. BTW, with the key on, and the leveling system switch in the driving or road position at least one of the valves shown will be warm all the time.

[MangoMike]

Mel Torme,

If you do have to replace one of the solenoid control valve as Jon has outlined here's another howto with additional information.

Picture 1.jpg


http://www.prevoman.com/Pages/Manifold/Manifoldpg1.html

Mike

[tdelorme]

Well, the strange thing is the coach stays level..My bus barn's floor is level so I just back in and shut her down. Stays level, but, the aux. compressor does cycle on every two or three hours. Runs for 30 seconds or so and shuts down. Now the 5 port valve that is leaking seems to have a small crack in the valve body. When I spray the valve and the bubbles start, I can reach up with my hand and squeeze the valve body with my fingers and the bubbles stop. If the valve body has several parts and one part is loose, I can't find a way to tighten it up.
My questions now are, #1. Do I need to bleed the systen down (and shut off the aux compressor) before I remove this valve or look for a shutoff close by? and #2. Is removing the valve going to bleed the whole air system down (air bags included)? Or is it impossible to know this for sure. Older Liberty, 1991. #3. Is the solenoid valve a Prevost part and do you know the part #.
Thanks, Jon And you also, Mango, I have printed the solenoid valve change out info and put it in my book of knowledge. (very small book)

[truk4u]

Ted,

Just bleed all the air out of your aux system, making sure your compressor is shut down. The only effect will be the loss of pocket doors, stair slide, engine bellows, gen bellows, etc. and will not effect your brakes or air bags.

It would help if you included your year and conversion as a signature for folks with the same vintage.

[Jon Wehrenberg]

Ted,

I need to make a correction to what I posted above. If that is the three port valve on the steer compartment rear wall immediately below the five port valve IT DOES HAVE AUX AIR SUPPLY COMING INTO THE BOTTOM PORT.

I was prompted to verify what I told you earlier and if you have the Prevost installed plumbing that valve supplies aux air to the five port valve that is used when parked to hold air in the front air bags, or when driving to direct aux system air to the ride height valve.

You are correct in that your aux pump is likely running due to that leak.

If you only replace that valve you will dump all aux air as soon as the lower 3/8 diameter hose is disconnected. You may want to lower the front and bleed aux air out as Tom suggests just so nothing will surprise you. The front end should not lose air, but with so many design changes and converter modifications I can't say your front end will not drop.

[tdelorme]

OK, Jon, so I guess that will be a different Prevost part number. The part # on the valve is a 16 digit number that I will see if Prevost can cross reference to. I'm not going to pull the valve till I have a replacement but I am going to clean the crack up and coat it with epoxy in case we want to use the coach before I get the new valve.
Thanks, Tom, I went in and fixed the signature to show the year and converter.

[BrianE]

Ted,

The folowing link will direct you to a Norgren distributor in your area. These valves are used in many applications and your local distributor will be familiar with the part numbers that are on the valve body. My local distributor sold me parts to overhaul my Norgrens and they also offered remanufactured valves for exchange. The cost of their services are much less than going to Prevost for replacements.

http://www.norgren.com/kip/distlocat...ibutorsAll.asp

[MangoMike]

Mel Torme,

Besides Prevost, I've also bought valves from these guys.

Norgren Distributor
Penn Air
York, Pa
717 840-8100 Dave in parts

Mike

[Jon Wehrenberg]

Ted,

Highly unlikely it is cracked. What you are seeing is a leak sideways past the end O rings on the spool inside the valve. Neither end of the valve body is sealed. On a Norgren valve air can leak through the valve (and not make bubbles) or out the ends of the internal spools and make bubbles as you see.

The Norgren number on that vintage Norgren has been superceded and the number I gave you is a good Prevost current part number.