I have a new to me 2009 Nimbus and my front and rear air pressure readings go down to 2 psi overnight. This is my 2nd DP and didn't experience this in my Country Coach, is this normal for Foretravel or do I have a leak? The coach stays level so it does not appear to be the air bags. any guidance would be appreciated.
You sure have several leaks dropping that fast or one big leak. It could be leaking out a fitting or a bad spot on a hose. These can be found with kids bubbles that have been put in a spray bottle. If this is a dead end then you have an internal leak through your protection valves (these should close at about #60) and the check valves at your storage tanks and the check valve in your air dryer.
Overnight we may loose #10 total overnight not down to #10.
Mike
Also make sure your auxiliary air compressor is working.
Do you know when the air dryer was last serviced?
No I don't, and thank you for the feedback. Any recommendations for a service center in the Phoenix Arizona area?
I believe it is as it goes on frequently.
If it is cycling often this could be the tie in valve to your main air system leaking or you could have a leak in a 6 pack, air bag or related piping or your slide seal system. This little compressor isn't there to keep the main air system full.
Mike
As noted by Mike (above), both of your protection valves (and possibly other valves) are leaking. They should maintain pressure in your F & R brake tanks at about 60 psi for at least a day or two. This is not a good sign, because the protection valves are "down stream" quite a ways from the air compressor. It is possible the valves are contaminated with white powder from a failed air compressor cartridge.
Your air leaks are working your Aux pump a bunch. My pump runs once or twice per day.
I fixed leaks in the air bladder systems and isolated the Aux pump from the level system as my coach sits level with out help from the HWH level system pad.
My air guages on the dash sit at zero all the time after sitting for several days. Aux air pressure is 90 psi and bladder supply pressure is 12 psi.
When the air system is pressured up, and you open the water drain valve on the wet tank, what comes out?
It sounds like I have 2 problems then.
1) The check valves are not working on my brake tanks
2) There may be a leak in the air bag or slide seal system.
Does anyone have a recommended service facility in Phoenix?
When the air system is pressured up, and you open the water drain valve on the wet tank, what comes out?
I will suggest you have a bladder seal leak and nothing else.
Using the Forum search tool, I found the following recommendation:
Great Service in Phoenix, AZ - Massey's Diesel and RV Repair (https://www.foreforums.com/index.php?topic=28571)
FOT has, on their website, a downloadable list of owner recommended service shops. There are 2 shops in Arizona:
FORETRAVEL (https://www.foretravel.com/owner-service)
Our speculating on possible leak sources (all real potential areas) may not be leading you to the source.
Absolutely, check for what comes out the tank drains and let us know.
Then, WITH COACH PROPERLY SUPPORTED and air pressure up, check everything with a soap solution.
jimgior13 has asked about a service center twice. They may be challanged to work on the system (knowledge or ability). We all assume that people do as we do.
jimgior13
Contact info for Phoenix
East Valley RV Specialist, 10020 E. Apache Trail, 866-846-7726, www.eastvalleyrv.com
Little Dealer Little Prices. 2350 W. Deer Valley, 623-889-3900, Little Dealer Little Prices | Arizona RV Dealer | Top 50 RV Dealer | Best RV... (http://www.littledealer.com)
Excuse my ignorance, but which wet tank?
You are not ignorant. You are following the exact same learning curve that we all go through. It seems daunting at first, but you will soon get up to speed. Continue hanging out here, read the posts, listen to the comments...before long
you will be answering questions instead of asking them.
Do you have a air system diagram for your coach? If so, look at it. Follow the path of compressed air after it leaves the engine air compressor. It will go the the air dryer, where moisture and oil are removed, and then to the first air tank in the system. This is the "wet tank", so named because it serves as a backup trap for water that gets past the air dryer.
Ideally, the dryer will remove all the water, and the wet tank will only receive dry air. If, for any reason, the dryer is not doing it's job then water will accumulate in the wet tank. You should on a regular basis open the tank drain valve to check. If you only get dry air - that's good. If you get any water, or oily looking wet whitish paste, then that is a sign of possible dryer failure. In that case, the dryer should be serviced ASAP.
The wet tank drain valve is probably located in the driver side rear wheel well, in front of the outside dual tire.
Thank you I'll go look for that now and post the results.
It's also possible to pay a good mechanic, one who is used to working with air brakes, to localize the leaks, mark and note their location, and present you with some options. Someone used to working on heavy machinery will have not only the safety equipment but a flexible back and good hearing. Think truck repair shop.
And to second what Chuck and Jeannie said earlier, it's a steep learning curve but it ain't rocket science. I am also a firm believer that anyone operating a heavy truck needs at least an overview on the workings of the braking system when they lay their foot on the treadle. This was my first area of study after our new-to-me Foretravel arrived.
Chuck,
Thank you for this clear concise description (Reply #17). It was a couple of years of ownership before I fully understood my air system.
Richard
Here in Canada to be able to get a license to drive a vehicle with air brakes you have to go thru an Air Brake course then sit an exam for a license. Driving without this license is against the law.
Johnh
I had Massey's in Phoenix ,April 2019 replace my original shocks with 8 koni far shocks. Plus replaced the green coolant with red fleetguard
Complete coolant.
Service mgr Tom is good. As mentioned, it's a very busy semi shop, but they had several coaches there.
Usually booked in advance, so call to explain your problem. Good luck
the pressure switch on my aux compressor had a pinhole leak in the diaphragm and would leak the system and have to cycle on every 20mins to keep up...new switch fixed it up..
Here are my findings so far.
I ran the engine and built up the pressure, shut down and went to the engine compartment. I could definitely hear a air leak coming from the right side as you look into the engine compartment. I sprayed soapy water but was unable to find an exact location, but there is a definite leak. Within minutes both front and back air tanks bled down significantly. While the engine is running air pressure is around 118 both front and rear - is this safe enough to drive with the leak?
I was unable to locate the wet tank for the air system - would it be close to the engine or in one of the basements?
If you mean to drive to a shop, yes but I would get it fixed right away. You Probably need to get under the coach but unless you
have suspension blocks don't go under. Did you open the engine battery door to find the leak.
1.On some of the Nimbus coaches they hid the air dryer on that side up behind the tag axle. It could be the purge valve has broken or has trash in it not letting it close. Or it could be a bad hose in that area.
2. Should be unless it gets worse.. How long has this been going on?
3. The drain should be just in front of the left hand (drivers side) duel wheel hid under the fender skirt down real low. The tank its self is hid above the differential.
Mike
Thanks Mike - back to the coach to look for the drain. I've only had the coach a month and noticed 2 weeks ago.
My wet tank bleed is in front of the drivers side drive wheel in the front of the wheel well.
Keith
Not the engine battery door but the rear engine access.
Leak seem to be coming from this (photo)
Shared album - James Giordano - Google Photos (https://photos.app.goo.gl/bw9wkADyxsqncu4GA)
That thing with the round black cap is your D2 governor. If the air is coming out the exhaust port then the governor may be/is bad. They are about $25 If the governor was telling the compressor to pump and never shut down then the over pressure valve would be sounding off on the wet tank.
Mike
On edit: That (a governor) is one thing you need to have as a spare that travels with you all the time along with the end wrench that it takes to change it out. If you aren't mechanical inclined find someone that will show you how to change it out as that is the heart of your air system. It isn't but 2 bolts and hose but important for you to be able to DIY
Thanks Mike. I see several D2's online - are they universal or should I get a specific part number off my old one.
Is is common for the D2 to leak when then engine is not running? I believe I read in an earlier post the leak can be heard with the engine off. I am not that familiar with the air system, but if there is air leaking from the D2 when the engine is off, would that suggest a check valve is not holding?
If after replacing the D2 governor* you still have air leaking there, change the air dryer. We'll tell you why later.
Art
*D2 Governor is the name given by Bendix.
To answer a previous question: Air is coming out of the wet tank when opened.
Only dry air?
No moisture., oil or white powder?
If so, that is GREAT!
Just dry air. Something is leaking near the D2 I can hear the hissing. Will investigate further on Tuesday
Your wet tank if it's in the same place as my U-320 will be in front of the rear axle . When looking from the engine cowling forward it is behind the engine and in front of the axle (behind it in relation to the front end of the coach).
Leak, plus, perhaps bad check valve.
Found leak at T fitting that seems to have slowed things down, but air still will go down into the 40's overnight and I read or heard somewhere that the check valve should stop it at 60psi - is that correct
In short yes the isolations valve should close at about #60. They (our coach has 2) are located on the front and rear tanks, which both are located up front.
I just saw you post about the governor from 3 weeks ago. In general Bendix D-2 governor different numbers are from part number changes over the years, whether the set point is adjustable or not, and what the set point is out of the box. Now cut in/cut out span is around #20 and is not adjustable. Cut out/cut in can be like #105/125 or 110/130 out of the box so they have 2 different part numbers. So any good truck parts store will have one on the shelf just ask for a D-2. Have you noticed what your cut out/in pressure has been? If so ask for one that is close to what you have saw on the dash gauge.
Mike
Do you have a air system schematic for your coach? If so, you need to study it so you understand the flow of air in the system. Doing so makes it much easier to diagnose problems and narrow down the possible location of air leaks.
The diagram below is a good "generic" depiction of a air system on a coach with tag axle and slide(s). It may not be exactly like your newer 2009 Nimbus, but it is probably similar.
If you reduce the air system down to the most
basic components, you have the air compressor, the air dryer, the wet tank, and the 2 brake tanks. Everything else is ancillary. The dash pressure gauges read the
brake tank pressures, because they are the most critical tanks. They power the brakes. The brakes save your butt.
Each brake tank has 2 "check" valves. The
inlet check valve keeps air pressure from escaping "backwards" in case of a big air leak UPSTREAM of the tank. The
protection valve is designed to retain a minimum of 60 psi in the brake tank in the event of a big air leak DOWNSTREAM of the tank. 60 psi is enough to provide braking so you can get the coach to a safe place to park. It also is enough pressure to keep the emergency spring brakes from activating. Hence the name "PROTECTION VALVE". They protect you in a emergency.
If you start out with full pressure (120 psi) in your air system, and after a short time (one night) your dash air gauge shows pressure below 60 psi, then you could have a leak either upstream OR downstream of the brake tanks. You don't know which check valve is malfunctioning. The only way to further pin down the leak location is to replace the check valves. Once you know both sets of check valves are holding THEN you can go hunting for the leaks.
Where is the Rear Air Tank located & best way to access it. Thanks
Raise coach and block with safety stands
Slide under front end where ever is good for you
Set up with your back next to the front axle
Look up to the front of the coach
You will see the 2 matching tanks in front of you just behind the back of the generator
On our coach the rear is the one on the passengers side but yours may be different.
Mike
Expanding on Mike's directions, there is one sure way to ID which tank is "Front" and which is "Rear". It
does require that you have the air system diagram for your coach.
When you crawl under the coach, you will notice that most of the air lines in the vicinity of the brake tanks are marked with white tags. The tags have numbers printed on them. The tag numbers correspond to the air line ID numbers on the air system diagram. By matching the numbers on the diagram to the actual air lines, you can positively determine which tank is which.
Note: You can't use the generic diagram I posted earlier for this ID method. It is
not specific to your coach.
Thanks Chuck - I was able to get my air diagram from FOT