One issue only determined after I purchased this fine machine. Is I have very slow air leak.
I can level the bus and after an hour have no detectable air pressure loss on the primary or secondary gages. In fact the primary will hold air for several days with no detectable loss. But overnight I get a definite list. The passenger side drops and she ain't level by morning.
Does your experience point me to look any any particular area first. I can start soaping every joint but if there is a common problem I'd like to start there. Without a shop and working this in a field/parking lot is not going to be fun.
Joe: on the other board at top in the articles section is a complete tutorial on the level low system unique to prevost. Prob in one of your norgen valves. Might cure it's self but you need to watch it very good . Bob. Everyone else welcome to watch it at prevostcommunity.com very educational on air leveling systems.
I had a leaking leveling valve on the rear of the side that was low - there are three leveling valves on the bus, two in the rear and one in the front. There should be no air leaking out from the exhaust when the bus is level and turned off. That's the simple one. The level low system uses a number of Norgren valves to control the height of the bus. There is a manifold in the compartment below the driver - another easy place to look for leaks. I second the tutorial - very helpful.
Steve
Are you sure it is a low level system or a HWH leveling system either way start at the manifold and the electric control valves plenty of places there for leaks have fun
It has to be a leak after the protection valve it closes at 70 lbs and will not let air into the suspension system that is why they drop
The bus setting for those years check the plastic lines the Texas rats love that stuff so do welding sparks and grinder sparks
good luck
Quote from: robertglines1 on August 02, 2012, 05:50:41 PM
Joe: on the other board at top in the articles section is a complete tutorial on the level low system unique to prevost. Prob in one of your norgen valves. Might cure it's self but you need to watch it very good . Bob. Everyone else welcome to watch it at prevostcommunity.com very educational on air leveling systems.
I found it and will watch it. The air diagram is scary!
Quote from: stevet903 on August 02, 2012, 06:06:54 PM
I had a leaking leveling valve on the rear of the side that was low - there are three leveling valves on the bus, two in the rear and one in the front. There should be no air leaking out from the exhaust when the bus is level and turned off. That's the simple one. The level low system uses a number of Norgren valves to control the height of the bus. There is a manifold in the compartment below the driver - another easy place to look for leaks. I second the tutorial - very helpful.
Steve
Can I get to the valves in the rear axle without a pit or lift? Are there connections near the passenger front (like in the spare tire compartment) similar to those in the steering compartment? or is the only thing over there the air bag connection?
Quote from: luvrbus on August 02, 2012, 06:08:05 PM
Are you sure it is a low level system or a HWH leveling system either way start at the manifold and the electric control valves plenty of places there for leaks have fun
It has to be a leak after the protection valve it closes at 70 lbs and will not let air into the suspension system that is why they drop
The bus setting for those years check the plastic lines the Texas rats love that stuff so do welding sparks and grinder sparks
I'll start checking all the exhaust ports I can find for leaks. If I find one (or more) is the best course to replace or rebuild the valve?
I vacuumed the bays last Saturday and did not see any signs of rodents. Maybe I'll be ok in that area.
Your in for a real education here LOL::: ck leveling valve first soapy water is your best friend here. Replace leveling valves-- if needed not that expensive... spray all over air bags and connections.. If you have any push type connections pay particular attention to them. I feel your pain. Bob
prevostcar.com is another good source for pneumatic diagrams particular to your coach--pre converter. takes last letter in your serial # plus last 4 digits(your unit number) If you need help getting thru their site just ask. Bob
They are scary Joe as my friend Bobofthenorth says a very over engineered air system on Prevost's don't crawl under the bus working on those it comes down in hurry play safe block it up or your wife and someone else will enjoy your bus
Those were always a problem that is why most have the HWH system and like Bob I feel for you could be a easy fix maybe not so easy
Need to look at system but if I remember correctly when you are in level low your level ing valves are out of system. I know they are. been about 4 months and 7 new norgen valves since I worked on it and 40 hrs studying diagrams. 8 new air bags.many feet of new air line.What a experience. Smile ..
5ea 24 volt coils 3 leveling valves 8 shocks 10 bushings Just thought I'd make someones day. Don't plan on doing it again!!! Bob
Hey Joe, I've been fighting a slow leak on the driver's rear for the past 5 years. I thought I had it at one point when i discovered the fitting at the top of the air bag was actually loose. I tightened that, replaced the seals in the little cast air cleaners (probably had nothing to do with the level low, but the system held air for a while longer after that). After several gallons of soapy water now, I've extended my system from holding level overnight to almost a week. If I'm going to be parked longer than that, I carry 4 stout wood blocks just for the rear. I set it down on the 4 blocks and then level it front to rear with the front air bags, they hold air forever it seems. Just make sure before you crawl under that beast you set some good blocking. That's a lot of weight being held up by mere air pressure. As TomC would say, "Good luck".
Will :)
Joe -
Just an FYI - I've seen brand new Gillig Phantom transit buses, with less than 250 miles on the clock, sitting cattywompus in the bus yard the morning after being delivered by the factory.
Such are the joys of air suspension!
FWIW & HTH. . .
;)
I have one bag that will sometimes hold for a few days just fine, then the next time we move and i adjust the level, it will go down in a day or so. Can't hear it leaking anywhere, soapy water doesn't show anything, i think i have it narrowed down to a worn o ring in the push-pull knob for that bag. It will leak down about 1 lb an hour. Need to find the right size and shape, (Think they are a flat o ring? ) and replace. Just a pain to get to because i have to take out the seat to get to it.
Thanks for the many posts and suggestions.
Here's a good post on how to make a bubble solution -
http://www.busconversions.com/bbs/index.php?topic=20295.0 (http://www.busconversions.com/bbs/index.php?topic=20295.0)
The glycerin or corn syrup makes it last longer and helps you to see the smaller leaks...
I have an 85 Prevost and I fought my air leaks for a few years until I finally put on a set of Big Foot levelers.I just love the system and my only regret was I wish I would have done it when I first did my conversion.I full timed for seven years so I could justify the cost.I like the fact when you set up you dump the air out of your bags and your bus is rock solid.Makes a big difference when you are in high winds and big storms.
Don
"I'll start checking all the exhaust ports I can find for leaks. If I find one (or more) is the best course to replace or rebuild the valve?"
Joe,
I have found that the internals of the Norgren valves get corroded and the bores pitted. They will leak and work intermittently. "O" rings looked OK. Thus, in my experience, there is no choice but to replace the valves. A careful, difficult analysis can identify the bad valve/s to minimize the number changed. One reason the valves corrode is from moisture in the air system. Make sure your air dryer has been changed.
Ed Roelle
Flint, MI
Quote from: edroelle on August 03, 2012, 09:27:29 AM
"I'll start checking all the exhaust ports I can find for leaks. If I find one (or more) is the best course to replace or rebuild the valve?"
Joe,
I have found that the internals of the Norgren valves get corroded and the bores pitted. They will leak and work intermittently. "O" rings looked OK. Thus, in my experience, there is no choice but to replace the valves. A careful, difficult analysis can identify the bad valve/s to minimize the number changed. One reason the valves corrode is from moisture in the air system. Make sure your air dryer has been changed.
Ed Roelle
Flint, MI
Changing the dryer is on the do it soon list. I'm still going back thru the record I have to see when specific things were done. Ive got to look for that one again.
Thanks for all the replys.
Joe,this is off topic kinda on that but did you find any reason or paper work on why the heads and oil pan have been taken off before that part scared me on a lo mileage 8V92 engine ? Low oil pressure and overheating will shut a DDEC down
I am just curios why the heads and pan were remove and both heads were removed
Quote from: luvrbus on August 04, 2012, 07:26:36 PM
Joe,this is off topic kinda on that but did you find any reason or paper work on why the heads and oil pan have been taken off before that part scared me on a lo mileage 8V92 engine ? Low oil pressure and overheating will shut a DDEC down
I am just curios why the heads and pan were remove and both heads were removed
Not sure if you have confused Joe(s) or buses. But to directly answer your question. This bus had a complete rebuild about 20,000 miles ago Or when it only had about 80,000 miles on it.
According to the PO it was right after he purchased the coach. He was on I-70 west bound out of Denver and he drive it till it seized. Stewart and Stevenson did the rebuild. They did not try and rod the radiator. New radiator from prevost. Blamed on the use of the wrong coolant. All 8 cylinder kits. new main and rod bearings. new injector assembly. Below is the summary from the bill. (yes I asked and got papers on the advertised rebuild). I never got a clear answer as to why the DDEC did not interlock it down but was told all those systems work now.
Engine runs good. No leaks as it sits and it did not burn/leak any oil on the 1000 mile trip.
COMPLAINT:ENGINE SEIZED
CAUSE:OVERHEAT,RADIATOR PLUG,
CORRECTION:REMOVED AIR BOX COVERS,INSPECTED CYLINDERS,ALL CYLINDERS SCORED,REMOVED
CYLINDER HEADS,FOUND SEVERAL PISTONS SEIZED IN CYLINDERSj
DRAINED OIL,REMOVED OIL PAN,REMOVED ROD CAPS,REMOVED CYLINDER KITS,
CHECKED CYL HEADS FOR CRACKS AND LEAKING,HEADS CHECKED GOOD.INSPECTED
INSIDE OF RADIATOR,FOUND RADIATOR CORES PLUGGED SOLID,ORDERED NEW RADIATOR FROM
PREVOST.BUILT AND INSTALLED NEW CYLINDER KITS WITH NEW ROD AND
MAIN BEARINGS.INSTALLED OIL PANJNSTALLED CYLINDER HEADS,
OVERHEADJNSTALL VALVE COVERS,HOSES,P1PING AND EXHAUST.
INSTALL NEW RADIATOR,FILL WITH OIL AND COOLANT,START AND
ROAD TEST,ALL OK,
Joe, to cause that the PO must have been using the override the DDEC is one smart cookie it has to be human stupidity to cause that the ECM is in full control unless a owner out smarts it
I just noticed the engine had been gone into is why I asked a rebuild at 80,000 miles unbelievable if it was warranty work the whole engine would have been replaced
I bet that was a 12 to 15 thousand dollar you take care of the 8v92 and it will serve you well for years
thanks for the info
good luck
Quote from: luvrbus on August 05, 2012, 10:54:23 AM
Joe, to cause that the PO must have been using the override the DDEC is one smart cookie it has to be human stupidity to cause that the ECM is in full control unless a owner out smarts it
I just noticed the engine had been gone into is why I asked a rebuild at 80,000 miles unbelievable if it was warranty work the whole engine would have been replaced
I bet that was a 12 to 15 thousand dollar you take care of the 8v92 and it will serve you well for years
thanks for the info
good luck
He would not tell me he used the override, but when I was asking him what happened, he left me with the impression it was his fault.
It was a $14,000 bill.