-
Air Leak or Pandora’s Box ??
-
I will check that system of Hector’s out. They replaced 3 vavles and some fitting this trip but not air bags because bus would not raise to ride height. Said bags looked good. When I called to pick up , they said It dropped on one side over night and they kept it another 2 days to find leak. . Called and Supposed to take it up in the next week or 2 as I can find time. If I could find someone in San Antone or Houston I would take it there as they are a hecka a lot closer to my ranchito. Thanks for the insight Jon.
-
Here we go again……….I was under the impression that repairs of the leans had changed into one in which some practical consideration is given to the task. From your post it sounds as though you have spent a fair amount of money for replacement parts, and yet more time and money was consumed trying to figure out why that didn’t fix the problem. Add in your costs in time and fuel and pretty soon the cost gets disproportionate to what was actually accomplished.
Everyone whose coach does not have the leans can count on repeating this experience unless some thought is given to the best way to avoid it.
Here are some numbers for all to consider……….
8 air bags…………………$1200 to $1500 (just a guess)
Installation time…………1.5 hours each (that’s a maximum based on my experience)Consider the above to be a total of $3000 and that is for the entire coach.
Norgren Valves………….$800 (another guess)
Installation time…………..1/2 hour each (based on my experience)Consider the above to be a total of $1300 also for an entire coach
My guess is that with some shopping and negotiating an owner could refresh the entire underside of the coach including shocks but not including brakes for well under $5000 instead of spending a large part of that to chase a leak on one of the three suspensions. If an owner wanted to spend the time to do the work less than $2000 in parts and several days of work accomplishes the same thing.
Chasing leaks in a suspension we eat up the same number of hours easily unless someone is very lucky.
Prevost will not (at least has not) quoted the prices above but I’d want them to do the work unless you can connect with a qualified mechanic. I would negotiate with Prevost rather than accepting their quote prior to starting the work. One thing to be aware of is that once a project like this begins it is the perfect time to evaluate everything including shocks, ride height valves and anything else that is aging or giveing signs of trouble because getting the bus set up to change air bags opens things up to get at everything else and the time involved is less than doing each job individually.
Just my opinion.
-
Jon, They replaced ride height valves this last trip, also 4 new shocks. I don’t have the invoice in front of me of I could post the vavle part numbers. Actually the bus didn’t lean this fast before they started the ride height problem . It would go down but would take a week or 2 and would settle the same at all corners. I’m not at home and the wife called a day after I left for my shop and a day after I picked in up from Prevost and thought it was going to turn over. I told her it’s okay because it’s in the Hay Barn and it will just gentley fall on the hay. Think I will get them to replace all bags and go from there. I still have a welding shop out in West Texas will build ramps and stands and will start doing/checking my problems after this or at least to see what’s under there. Thanks for all the insight.
-
Glen,
If you took it in to cure the leans, and their “fix” was to replace ride height valves insist on getting your money back.
The ride height valves have nothing to do with the leans. Even if a ride height valve is puking air by the bushel, as soon as you turn off the key it is in essence taken out of the system.
If you have the leans look at the five port Norgren valve or any of the associated air bags as likely sources of the problem. It could also be a three port Norgren depending on which part of the bus is leaning, or any of the fittings within the system that is leaning. That’s it. Nothing else.
The problem in curing the problem is finding the leak because the leak can “hide”.
Before you return to arm wrestle with the folks that you want to fix the problem, study the articles relating to the air system and especially any that relate to the suspension on this site. Hector’s tutorial is excellent. Once you understand the fundamentals of the suspension(s) you will be in an excellent position when it comes to directing the repairs to your coach.
-
Jon, I took it in because the bus failed to raise and had to do it manualy. Just told them to replace anything else that looked suspect. They also performed 4 recall notices that had never been done. They also changed trans fluid since coach had 63,000 miles on it. Had one shock leaking and they were going to replace it. Told um do um all. They got coach to rise on start and parked it out back and plugged in. Tech went out next morning and service manager called and said in leaked down on one side overnight. They kept it another 2 days and said it was ready. I will stay with it next time and see how it goes. If I had a way to get it off the ground and blocked, I would look at it myself. Will get a setup so I can get under next time safely.
Thanks for the info.
-
Anytime a coach that has gone to the driving or ride height in the previous use, but fails to do so the greatest probability is that the coil on the solenoid valve that controls that function has failed. On the 5 solenoid manifold it is the middle coil, on 4 solenoid manifolds it is likely to be the third solenoid coil from the bottom.
There are other reasons why a coach will suddenly not come to the driving height such as bad level low switch (contacts) or bad solenoid valve, but they are less likely. If a coach will come to the driving height in two of the three positions (left, right or front) it is likely the problem is with the 5 port Norgen valve or the ride height valve associated with that position.
-
I could raise it up with control switch on front and back left and right. It wouldn’t rise on it’s on. My mechanic checked all valves and coils under floor board. All good there. I. Had to do so manually to make it up to the shop in Ft Worth. I’ve looked at schmatics and have a basic understanding of system, and I do mean basic. When I get everything situated for lifting I will start doing some of the repairs myself. Or at least try. Time is my problem now with working on the bus myself. In a couple years I will be retiring from my business and will have all the time in the world. That’s if these dang cows will take care of there selfs at the ranchito. Thanks Jon for all the help.
-
Glen, without seeing your coach or having a chance to do a test I can say with conviction that if you have the level low selector in the driving or ride height position and none of the systems go to the ride height the ride height solenoid or its coil is bad, or the level low control switch is not allowing power to pass to the solenoid coil.
Unless you have an aux air system filled with water or some obscure system related issue of a similar serious nature that makes if fail in an illogical manner, it is unlikely to be anything else, despite what someone has told you.
If you want to get into it on your own to diagnose the problem email me and I can walk you through a step by step methodical process to isolate the problem quickly.
-
Jon ,
Prevost fixed the rise part a couple weeks ago at there Ft Worth Shop! Now I’ve got to take it back because it will drop on left side overnight. Gonna replace all air bags. They are original. Told um to do it a couple weeks ago but somehow didn’t get on the ticket. Thanks for the help!
glen s.
-
Mine use to drop to left in two days ,,, replaced all bags and it dose the same thing unless i leave the level air control at 180 deg. from driving posisition … Why i don’t know why but that keep it level, maybe try that first.
-
Thanks David, will try that in the morning, Told Prevost to replace bags but they said they looked good no cracks. Can’t believe that. I bought Bus off one of my customers that had passed away many years ago. I guess the 63000 miles they considered low. But as you know rubber deteriorates over time.
-
David and Glen…….
The suspension system logic has evolved over the years and I am not familiar with the nuances of your vintages. I am certain however both of you have the system logic that requires a minimum aux air system pressure of about 30 PSI to keep the 3 port Norgren valves between the tag and drive axles from dumping tag axle air bag air.
That being the case both of you can verify that by airing up the coach, getting it level, and then slowly bleeding off aux air until it gets down to near 30 PSI, at which point if that is the cause of the leans you should hear air escape from the rear and the bus settle down.
It might be that when David leaves the level low switch in a manual position he interferes with the system logic and the air does not dump when aux air pressure gets low.
Hector has an aux air and suspension system with your logic I believe. Perhaps he can jump in. He is the expert on system logic.
-
Thanks Jon. Finishing up on my bus barn and will have everything I need to tackle these problems in the future if I can ever get the men back out to finish it. In the meantime, it’s Prevost. Don’t mind the cost per say but Prevoxt shop is about 41/2 hours north of me. Service manager told me they are opening a service center in Houston as we speak. Only 100 miles from me. Woo Who!
-
All of us that have a garage that we can work in will tell you that it is worth the price. I struggled to maintain our first coach on the floor of a barn. No pit, poor lighting, colder than you can imagine in the winter, but it kept me and the bus dry.
When we built our house in Knoxville I made sure the bus garage had good lighting, was plumbed for air, water, sewer and electric, and it had a pit beneath the bus. I thought I was in heaven. I did my own work on the barn floor, but it was a struggle. Now even though my garage is crowded and messy working on the bus is easy and the more I work on it, the more I learn and the more I learn the more comfortable I am on every trip.
-
I finished getting the air bags and shocks off of our H3 Saturday. Ours were also original but some even had threads showing so they were not going to last much longer. I am also replacing all the Norgren valves and the 3 ports for the tag axle have been the most aggravating to remove. I don’t know how they are on the XL, but on the H3 they are located on the inside tubing between the drive and tag axle. The only way to get to them is the small space between the transmission and the differential and it is all working above your head. I am going to replace all the tubing for the suspension as well. The old “while we’re at it” always sneaks in so I have changed the tranmission filter, will change the air dryer element and replace the brake chambers and slack adjusters.
WHEW!! I am tired just thinking about it!!!
Log in to reply.