Air Bags

[bcullifer]

I have a 2008 390QS Berkshire MH, For some reason the Right rear air bag want level up when it time to go. I can hear air coming out when I get out of the coach. I need help, Thank you all
Bill

[GoneSouth10]

I had a very similar situation with my 2015 34QS. I always had a little "pfffttt" from the right front wheel well when I'd step on and off the coach. Then about a month or so ago, I noticed that there was a sort of constant, but much softer "ppfffttt", like a constant air discharge. After digging around behind the wheel, I found I could reach the lever on the air suspension system and when I'd wiggle it, I could hear the discharge rate change. (My right rear wheel has the same set up, which is where you seem to be having the problem).
After talking to my Freightliner guy, we figured it was a very small air leak from the air line/coupling. My compressor more than keeps up with the leak, so I haven't yet taken the time to dig around under there, do the soap and water deal to find the leak, and do the simple (I hope) repair of cutting off about a 1/2" of air line and sticking it back on the coupler. My guy told me the ends of those air lines sort lose the integrity of the seal on the coupler after a while.
It sounds like you may have more than a small leak and your compressor can't keep up with it. You may need to just dig around, find the end of that air line (maybe it has completely popped off?) and see if that's where the air leak is coming from.
Good luck!

[A32Deuce]

Do these DPs have separate tanks and compressors or all the same compressor and tanks? Because if not and its the same air for ride and brakes, Get It Fixed ASAP!

[GoneSouth10]

Yes (Not sure if you're responding to the OP or my post). You can drive them with functioning brakes without (inadvertently) airing up the suspension - but you feel every rock, pebble, crack and tar snake on the road!! (Don't ask me how I know . . . ) After about 1/4 mile, you'll be pulling over to figure out why it feels like you're driving over a washboard . . .
Just to provide some perspective on the small discharge on my coach, when I park my coach after driving (with the air bags filled !), the air slowly discharges out of the bags so that after about 72 hours, the coach has "settled" down about 4" or so and the air bags are empty. When I start it up, the bags fill and the coach rises back up that 4" or so. Now, that "settling down" process takes about 48 hours instead of 72 hours. While driving, the bags fill up fine and remain filled, providing that smoooooth Freightliner ride!
Oh, and the brakes work, too
(Perhaps a different thread, but it's my understanding that air brakes function by the air pressure keeping the brakes "disengaged" and pressing the brake pedal actually releases the pressure so that the brake engages - a safety feature so that if you do lose pressure to the brake system, the brakes engage, not the other way around . . . but happy to be educated on this understanding).

[gordonsick]

I agree that it is not unusual for the air bags to deflate themselves. When I do maintenance under my coach, I usually leave the air bags inflated rather than lifting the coach with the levelling the jacks. This allows me to place blocks under the jack feet as a safety system when they are retracted (and they won't retract any more).

When I'm working on the rear of the coach, held up by the air bags, I put a 20 ton jack under the rear engine mount bolt, which is in the centre of the coach. I raise the jack a tiny amount to that it has pressure on it, but isn't lifting the coach. By the time I'm finished servicing my coach, I have to retract that jack a lot, because the air has leaked out steadily.

–Gordon

[gordonsick]

Originally Posted by GoneSouth10

Yes (Not sure if you're responding to the OP or my post).
[snip]
(Perhaps a different thread, but it's my understanding that air brakes function by the air pressure keeping the brakes "disengaged" and pressing the brake pedal actually releases the pressure so that the brake engages - a safety feature so that if you do lose pressure to the brake system, the brakes engage, not the other way around . . . but happy to be educated on this understanding).

That is a description of the fail-safe feature of the air brakes, but not a description of the normal operation of the air brakes.

For normal operation of our air brakes, depressing the brake pedal allows air to enter the brake chamber, which moves a piston to engage the front and rear brakes.

But, there is a "failsafe" emergency braking system, for the rear brakes, in which absence of system air pressure lets air out of the parking brake air chamber. This air is normally pushing against a heavy spring that will engage the parking brake if there is no air in the chamber. When you pull the yellow diamond knob to park, you are dumping air from that chamber, which engages the parking brake. The only way to release the parking brake is to air up the brake system, and push the diamond button down.

You may recall the alarm that sounds when you start the engine at the beginning of the day. This is coming from the air brake system, warning you that the system does not have enough pressure to operate the brakes properly. If this alarm sounds while you are driving down the road, your brakes are losing air pressure, but will work for a while. You should pull over to a safe parking spot and park. If you don't, the parking brake will come on while you are in a driving lane, and you are stuck until a heavy duty tow truck arrives!

There are three air tanks for the air brake system. One is for the rear brakes (Primary System, with 1 on the air gauge), and another is for the front brakes (Secondary System, with 2 on the air gauge). The third tank does not have an air gauge, but feeds air into the other tanks.

I believe that it is the third tank that supplies air to the air suspension, the air horn and the air chuck on the front firewall.

All three air tanks have a drain valve at the bottom that should be periodically opened to drain water out of the bottom of the tank. The valves are connected to lanyard loops that are in the front wheel wells. Two on one side and one on the other. An easy way to find the lanyards is by parking the coach with the wheels turned sharply to one side.

As an aside, when I took delivery of my coach, I couldn't find the lanyards, but I knew that they had to be installed by law. So, I asked my dealer to show me where they were, when I went in for service. I foolishly assumed that this would be common knowledge that even their sales people would know. Instead, I was presented with a bill for one hour of labour as the service technician combed through my coach to find them. (The Freightliner manual does describe how to find them, as I recall.) For me, that was the crowning glory of my dismay for the quality of service at that dealership, and I never went back after we finished the warranty period. And, I set about writing the manual for my coach. (Egads, I just realized that this procedure isn't in my manual. I'll put that in for my next revision.)

There are lots of manuals out there to describe how our air brakes work. I've got links to some in my manual below. Just not (yet) the procedure for draining water from the tanks.

–Gordon

[Eric B FR Diesel]

Originally Posted by bcullifer

I have a 2008 390QS Berkshire MH, For some reason the Right rear air bag want level up when it time to go. I can hear air coming out when I get out of the coach. I need help, Thank you all
Bill

Bill what year is your coach? Also there are two air gauges for each side of the coach what is the PSI that they are reading?

[Lincman983]

Bill,
Good afternoon. This is Mike from Forest River. found a fireside chat from Freightliner Custom Chassis that help better understand the airbag system on your coach. This publication was put forth in 2017, it is still pertinent to the vintage of your coach, however some minor components may have changed the majority of the main features are still relevant. If you have any other questions our concerns please do not hesitate to email me at mwinterrowd@forestriverinc.com. Have a great day

[GoneSouth10]

Originally Posted by Lincman983

Bill,
Good afternoon. This is Mike from Forest River. found a fireside chat from Freightliner Custom Chassis that help better understand the airbag system on your coach. if you have any other questions our concerns please do not hesitate to email me at mwinterrowd@forestriverinc.com. Have a great day

Mike - I haven't had a chance to drill down on that PDF, but is it applicable to a 2015 chassis? If not, do you have one for the 2015?
Thanks!

[Lincman983]

Gone South,
I do not have a publication from 2015 but I do think that the 2017 pdf still has pertinent info on the air ryde system, however some minor components may have changed the majority of the main features are still relevant.

[gordonsick]

Mike's Fireside Chat slides are nicer than other ones I've downloaded, because they include the speaker notes. Thanks for posting them.

The Fireside Chat is dated Feb 2016. It is relevant to my 2015 Berk 34QS. Probably the only thing mentioned in it that is extraneous is the V-Ride rear suspension, which we didn't have in 2015.

–Gordon

[GoneSouth10]

Perfect - thank you both Mike and Gordon!! I look forward to spending some quality quarantine time perusing this presentation!

[Eric B FR Diesel]

Originally Posted by GoneSouth10

Mike - I haven't had a chance to drill down on that PDF, but is it applicable to a 2015 chassis? If not, do you have one for the 2015?
Thanks!

Here is a link to the spec sheet from freight liner chassis that was used for your model year... not sure if this is what you are looking for.

https://cdn.fccchq.com/specsheets/20...ire-340-HP.pdf

If this is not what you are looking for it wouldnt hirt to call the 1-800-FTL-Help number and ask FL any questions.

[GoneSouth10]

Originally Posted by Eric B FR Diesel

Here is a link to the spec sheet from freight liner chassis that was used for your model year... not sure if this is what you are looking for.

https://cdn.fccchq.com/specsheets/20...ire-340-HP.pdf

If this is not what you are looking for it wouldnt hirt to call the 1-800-FTL-Help number and ask FL any questions.

Awesome - gracias!

[gordonsick]

Originally Posted by GoneSouth10

Perfect - thank you both Mike and Gordon!! I look forward to spending some quality quarantine time perusing this presentation!

Gone South,
I assume that you will also use some of that spare time to read my manual, since we have the same year and model of coach, it doesn't get much closer!

The Fireside Chat slides are from Camp Freightliner, I believe, so there are versions from various years, but things don't change much amongst the various versions.

The slides contain a lot of useful information, but you shouldn't rely on the filter part numbers and diagrams that they have. For example, Slide 81 shows 4 different fuel-water separators. The yellow one on the right has a plastic inspection bowl for water in fuel. It is the correct one for our ISB 6.7 coaches, which have that filter mounted on the frame. The caption incorrectly suggests it is only for other engines (C7 and MBE). The red filter beside it is listed for the ISB engine, but it is the wrong one for our coaches. I did follow some erroneous information for my first filter purchases, and this looks like one of my information sources. The correct filters can be found using your VIN number on the Access Freightliner website (as shown in slide 34).

Since this thread started with airbag inflation problems, it is worth noting that the Fireside Chat does not discuss one of the major airbag problems on our coaches. My manual discusses it and there is a lot of discussion on this forum about it. The only manufacturer documentation I have found to mention it is a very fleeting reference in the Equalizer manual that I linked above.

The problem is that, on rare occasions, the air bags do not inflate at the start of the day, and you are running on the rails with a very, very rough ride. So you need to check that the air bags do inflate after you start the engine and air up the system. You can see the coach rising relative to the wheels. The cause of the problem is an interconnection between two parts that are installed by Freightliner, so they really should discuss the problem in their documentation and they don't.

The airbag inflation problem arises when the jacks are retracted by the Equalizer System, but there is not full air pressure in the system within a specific time period (two minutes, I think) of the jacks being raised. The Equalizer system sets a temporary switch on the air system to inflate the bags, but won't do it if the system isn't aired up in time. As I say, my manual discusses how to solve the problem.

I don't think this is the problem of the OP, however, because he is only finding that one airbag fails to inflate. The others are inflating, so they are getting the switch signal.

–Gordon

[GoneSouth10]

Originally Posted by gordonsick

The problem is that, on rare occasions, the air bags do not inflate at the start of the day, and you are running on the rails with a very, very rough ride. So you need to check that the air bags do inflate after you start the engine and air up the system. You can see the coach rising relative to the wheels. The cause of the problem is an interconnection between two parts that are installed by Freightliner, so they really should discuss the problem in their documentation and they don't.

The airbag inflation problem arises when the jacks are retracted by the Equalizer System, but there is not full air pressure in the system within a specific time period (two minutes, I think) of the jacks being raised. The Equalizer system sets a temporary switch on the air system to inflate the bags, but won't do it if the system isn't aired up in time. As I say, my manual discusses how to solve the problem.

I don't think this is the problem of the OP, however, because he is only finding that one airbag fails to inflate. The others are inflating, so they are getting the switch signal.

–Gordon

First, thanks for the heads up on the information discrepancies.
Second - Haha - yup, that "riding on the rails" issue was referenced in one of my posts and I recalled your rather vivid description of it happening to you as well! In my case I think I drove for less than a 1/4 mile before realizing something was amiss. That said, that phenomenon does prove that there are two separate systems for brakes and the suspension. And yes, the "solution" to that issue was like chasing a ghost, but eventually stumbled on a "break camp" routine that ensures the filling of the bags.
Hope all's well up in Calgary and hope that Alberta Beef gets back on line soon!

[gordonsick]

Originally Posted by GoneSouth10

[snip]
Hope all's well up in Calgary and hope that Alberta Beef gets back on line soon!

Thanks for noticing our Covid problems in beef processing plants. That's a worry.

But, not the only worry for Alberta. Low oil prices are killing us, especially since a lot of our oil is heavy oil. And, we are a favourite target of climate alarmists who find it entertaining to do whatever they can to shut down our pipeline construction that would take oil and gas from Alberta to tidewater. We've been hit by Obama (Keystone XL to the Gulf Coast), Prime Minister Trudeau (Energy East to the Atlantic and Gateway pipeline to the Pacific). The well-funded activists work through lawyers and aboriginal groups with unsettled land claims, etc.

Offsetting this, we have some beautiful scenery and wonderful camping, when it reopens after Covid.

–Gordon

[lefaivre]

Originally Posted by gordonsick

Thanks for noticing our Covid problems in beef processing plants. That's a worry.

But, not the only worry for Alberta. Low oil prices are killing us, especially since a lot of our oil is heavy oil. And, we are a favourite target of climate alarmists who find it entertaining to do whatever they can to shut down our pipeline construction that would take oil and gas from Alberta to tidewater. We've been hit by Obama (Keystone XL to the Gulf Coast), Prime Minister Trudeau (Energy East to the Atlantic and Gateway pipeline to the Pacific). The well-funded activists work through lawyers and aboriginal groups with unsettled land claims, etc.

Offsetting this, we have some beautiful scenery and wonderful camping, when it reopens after Covid.

–Gordon

Originally Posted by bcullifer

I have a 2008 390QS Berkshire MH, For some reason the Right rear air bag want level up when it time to go. I can hear air coming out when I get out of the coach. I need help, Thank you all
Bill

I had the same problem with my 2012 390BH60 last year.

I was convinced when I took my unit into Freightliner in Calgary that I was going to need a new set of airbags.

Later that day I had a very pleasant surprise when they informed me that a complete inspection of the unit had only pointed out a leaky coupler and the bill was less that 200