You are not logged in or registered. Please login or register to use the full functionality of this board...

High air pressure
#1
As the coach sat for the last 2 years in a building, the previous owner came to it every couple of weeks and started the engine to build air and make sure all is fine. About 4 months ago he noticed that the air was not coming up and upon further investigation they found out that the engine air compressor was not working right. A new engine air compressor was installed along with a new air dryer and D2 governor.

As I drove it home from Monroe LA, I noticed that the air gauges were cycling a lot between 95 and 120 or so but I knew I had 3 leaks upfront- the 60psi safety switch on the parking brake was leaking, the SR-1 relay valve on the other side of the firewall next to the 6 pack was blowing air out of the bottom and 2 of the 1/2" air line elbows on the brake pedal manifold had minor leaks.

Once I got home, I fixed all these fast. I can still hear a leak around the front driver wheel (airbag, connection or brake chamber) and will sort it out shortly.

Today I had to drive it to Duncan RV in Elkhart to have a new driven windshield installed tomorrow.
With all the front air leaks fixed the gauges were staying nice at 100 to 120 psi cycling at idle.

But..once I started driving, both gauges were pegged to 150 psi, then cycling down to 130 not less.....the only time they went down to 100 is when I was at a stop light and had my foot on the brake. Once I started driving again back to 150 psi....I think this is rather high air pressure. Am I wrong ?
Is it possible that the new air compressor and air dryer when installed were not adjusted properly ? Or the wrong D2 governor ?

What should be done ? I have to drive it Thursday to WW Williams in Grand Rapids for the oil service, air bags replacement and height valves replacement but wonder if I have to do something before that......Don't want to blow up an airbag or brake chamber diaphragm and the highway if the air is too high an stays high like this.

Any advice ? Thoughts ?

Thanks
Marius
1997 #440
Reply
#2
More I think about it, the more I think that there has to be something wrong with the AD9 Air dryer purge valve not opening at 120-130 psi.
At idle the D2 governor will purge at 120 psi. I can hear it.
Once driving, if the D2 opens to purge at 120 psi and sends air through the line to the dryer. If the dryer purge valve is stuck closed or sticks, the system will build pressure to 160 psi...Am I on the right track ?

Wondering if there is an adjustment for the purge valve on the air dryer...maybe the mechanic messed it up when they installed it. With all the air leaks I had in the brake and aux circuits the system was bleeding off pressure on its own.
Marius
1997 #440
Reply
#3
Since this problem started after the mechanical changes it is clear that something is hooked up incorrectly. The governor's pressure sensing line should be connected downstream of the dryer and the line from the governor to the compressor unloader also goes to the dryer control port. If it is hooked up any other way things will go funky. Get a diagram of the port connections for the governor and compare that to how yours is plumbed. You will find the problem.
Jon Kabbe
1993 coach 337 with Civic towed
Reply
#4
Went back to the coach today and checked everything. It is hooked up correctly. The new Reliabilt Tru-Flo compressor came with a new D2 governor when installed in May along with a new air dryer.
The way it is installed on the back of the compressor, the d2 governor is upside down so I took the plastic cap off ...then a bunch of water started coming out....Let it drain, started the engine is it puffs fine at 125 psi unloading the compressor. Played with the brakes, higher rpms, got it to come up and down several times...seems to be ok stationary.
Windshields just put in, can't drive it until tomorrow. Will see how it drives and if the problem is still there.
That much water inside the governor could have hydro locked .....possible ?
Have to get after the tanks and drain everything again. Must have a lot of moisture in the system if there was water in the governor.
Marius
1997 #440
Reply
#5
Marius, did you pick up your coach in Monroe, LA?
That is where I am located.
Steve Magown
West Monroe, LA
1997 Newell #458, one of the earliest slide coaches, 3 roof airs, 74 GMC Eleganza, 62 Vette, 67 SS 427 Chevelle, 07 GT3, 02 Boxter, 68 Toronado, 67 Toronado, RZR 800, 88 Mastercraft, 86 Ski Nautique, 02 Baja Islander
Reply
#6
Hm, water in the spring and exhaust chamber, that doesn't seem right. It's also going to cause problems in freezing weather startups if water continues to collect there. Was the water possibly coolant? The air coming from the reservoir has been dried by the dryer. If there is a cracked in the head of the compressor coolant could flow into the governor and out the exhaust port. With the governor mounted spring side down liquid would collect up to the level of the exhaust port. With liquid in that space I believe it's possible to liquid lock the governor at least for a while until the liquid can seep out the pressure adjustment parts.

The big question is where is the liquid coming from. Is it coolant, or is it not. I can't figure out how this much water could come up the tube from the top of the reservoir. But that may be a symptom of my limited imagination more than anything.
Jon Kabbe
1993 coach 337 with Civic towed
Reply
#7
I picked up the coach in Destin Florida. Rick had it in a nice storage building owned by a friend.

It was water. I let it drain, did not put the cap back on yet. Picked up the coach from Duncan with 2 new windshields and drove it to my building. No more high air. Worked perfect as it should. Unloaded at 125 psi and worked well.

BTW, if anybody will need front windshields for this vintage, model 2000, I guess.....be aware that the glass Newell gets is from CoachWorks and one windshield is $420. My bus had a crack from a stone in the driver side. When they put it on, it was obvious that it was a different looking glass.

The original that Newell put back in the day had a clear/grey tint to it with a green/blue top shading. The company that made that glass is out of business since 09. The replacements are clear/green-ish...look very nice but different. If you change one, you will end up changing both to match the look.
Marius
1997 #440
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)