Air bags and auto leveling

[Hummin Cummins]

I had pac brake airbags on my '95 2500 with manual fill and I really liked them. Looking to put bags on my '11 2500 and have it narrowed down to the pac brake bags or hellwigs. This time i will be using on board air and a leveling (height control) valve to automatically maintain ride height. I saw hellwig sells that type of system as a kit with a compressor, but they wont sell valve separate. I know I can get a valve elsewhere on line or at the local truck parts place.



Is anyone else using an auto leveling system? I see from searching most use the in cab control / regulator and gauge type system. Would like to hear feedback as to how the auto systems are working on our trucks.



Thanks

Chris

 

[NIsaacs]

I assume you are talking about overload bags? I don't think a leveling valve would work on this type since the springs are the primary system. With "air ride" then yes that is the way to go.



Nick

 

[Bob4x4]

Nick,they will work fine as long as you understand they will not go lower than your height with springs alone

 

[STEVEBROOKS]

Chris,

I have Airlift brand bags and their auto-leveling system on my truck. The system works like a charm, and the difference between using them and not when towing my heavy 5er is amazing. Let me know if you have any other questions.

Steve

 

[NIsaacs]

Nick,they will work fine as long as you understand they will not go lower than your height with springs alone

Thanks Bob, I did not know that. I figured the auto valve would be too much or too little air for a small movement bag. I would think it would require quite a volume of air to respond to the valve dumping and inflating?? Some times I think too much:-laf



Nick

 

[Hummin Cummins]

Steve,
Thats what I was hoping to hear. I was thinking mount the valve to the bed crossmember with adjustable linkage running down to the the axle. Either the axle tubing or the diff cover, depending on the length of travel needed for movement. The plan is to maintain the minimum psi in the bags for empty ride height and when loading the 5er, bags "should" automatically inflate to raise the truck back to the original ride height. Other question I have is would a valve with a dump port be beneficial? i. e. When getting ready to unhitch the 5er, dump the air and let the truck squat instead of running the rv's jacks the extra length to take the weight off the truck? Seems simple enough, but I always like learning from other's successes or mistakes.

 

[NIsaacs]

when loading the 5er, bags "should" automatically inflate to raise the truck back to the original ride height.

I am still having a hard time understanding this automatic system. Steve, maybe you can explain how it works?



Since in an overload air bag system you want the springs to take the majority of the weight, if the bags aired up to the normal height, all the loaded weight would be on the bags. Also, does it require two valves? I never figured you wanted the fill lines to be common with each bag. What am I missing here? Thanks



Nick

 

[Bob4x4]

http://www.haldex.com/en/North-Amer...nsion-Control-Systems-new/EGP-Leveling-Valve/
http://www.haldex.com/Documents/hbs...eling_Valve_Product_Bulletin_ L25013_9-01.pdf

 

[NIsaacs]

Thank you for the links. I can see where that valve would work great on air suspension systems but I am still a little confused as to how it works on overload's with conventional springs. I guess you would need to adjust the linkage for empty and loaded use??



Nick

 

[Bob4x4]

The link is adjusted empty at normal ride height,when you add a load the truck will start to drop-the valve will add air to keep it level. Remove the weight it will dump air to keep it at normal height

 

[STEVEBROOKS]

Chris/Nick,

My Airlift system has a magnet that is on the end of an adjustable arm that is clamped to the driver-side rear spring. Mounted on the frame is a sensor that, when the bed's empty, is located adjacent to the magnet. When the bed's loaded sufficiently or my 5er is attached, the frame squats down and the sensor then moves away (ie, below) the magnet which then triggers a small compressor to pressurize the bags. Using the arm, the compressor on/off trigger points are adjustable to account for personal preference, and the system will also automatically dump presuure too. There is also a manual pressure dump valve which can be pulled to release all system pressure. I hope this info helps.

Steve

 

[NIsaacs]

Since in an overload air bag system you want the springs to take the majority of the weight, if the bags aired up to the normal height, all the loaded weight would be on the bags.

Thank you Bob and Steve for taking the time to educate me, however the above quote is still muddy to me. I can't understand why you would want an empty ride height with a load. There would be no more weight on the springs loaded as there would be empty, all the weight would be on the bags.



On a true air ride system with only air bags to carry the weight, I can see where empty and loaded would be the same ride height.



Nick

 

[Bob4x4]

Thank you Bob and Steve for taking the time to educate me, however the above quote is still muddy to me. I can't understand why you would want an empty ride height with a load. There would be no more weight on the springs loaded as there would be empty, all the weight would be on the bags.

On a true air ride system with only air bags to carry the weight, I can see where empty and loaded would be the same ride height.

Nick

No,not all the weight. The springs still carry weight,some is carried by the bags,the amount will depend on the air pressure and size of the bag

 

[NIsaacs]

No,not all the weight. The springs still carry weight,some is carried by the bags,the amount will depend on the air pressure and size of the bag

Okay, it's making more sense now. Even if the control is asking for more air because the height has not been reached at the adjusted level, the lift on the bag has stopped at what ever capacity it has, based on bag size and the air pressure capacity of the system. That the springs, then take over the weight thats left over. I guess as long as that amount is enough so the springs can control the sway of the load, all is well. Dang, I hope I am not the only one that cant see the forest for the trees!:-laf Thanks again



Nick

 

[mwilson]

Okay, it's making more sense now. Even if the control is asking for more air because the height has not been reached at the adjusted level, the lift on the bag has stopped at what ever capacity it has, based on bag size and the air pressure capacity of the system. That the springs, then take over the weight thats left over. I guess as long as that amount is enough so the springs can control the sway of the load, all is well. Dang, I hope I am not the only one that cant see the forest for the trees!:-laf Thanks again



Nick

No, you are not alone. I understand air rides, leveling valves etc. as well as anyone in my field. This spring ride with automatic air assist is something different to me.



I keep locking up when I remember the bold print warning on any of these add on air bag kits which states "NEVER COMPLETELY DEFLATE BAGS, 10PSI MINUMUM PRESSURE MUST BE MAINTAINED" or something very similar.



So if the leveling valve lets all of the air out when you unhook from that big ol' fiver won't the bags be dead empty??? I picture the empty truck happily setting on it's springs with two pruney looking air bags beside them.



Or will the valve keep some air in the bags so that the truck rides like a bobtail spring ride tractor and your teeth keep banging together on every expansion joint???



Or even worse every time the truck bounces empty the air bags try to fill and you recieve a double rebound bounce if you want to call it that.



I read about these on the Air Lift website, checked out the nifty, groovy electric eye leveling valve and all that. I am having trouble seeing the auto level and dump valve feature being all that great when coupled with a spring ride truck versus an in-cab control system.



Now if the truck was full air ride then Hell Yes, I would be first in line. Nothing on the planet any better than full air ride.



If you are considering adding a manual truck style leveling valve at least get one that is rated for "rapid response".

Yes, there is a difference in them even though they may look the same.

Also if you want the dump feature there are leveling valves that have that feature built in as well.

No power required, there is a simple shuttle built into the leveling valve. You install an air toggle in the cab that has access to system air pressure. Run a single air line from that valve to the "dump" port on the leveling valve.



When you apply air it moves the shuttle which blocks the inbound air to the bags and allows the air already in the bags to exhaust.



EASY PEAZY, and a proven design.



Here are a few examples, if one catches your eye I can give you the attributes.

http://www.midwestwheel.com/\specials\catalog0\38Height Control Products13007242012.pdf



Mike.

 

[NIsaacs]

No, you are not alone. I understand air rides, leveling valves etc. as well as anyone in my field. This spring ride with automatic air assist is something different to me.



I keep locking up when I remember the bold print warning on any of these add on air bag kits which states "NEVER COMPLETELY DEFLATE BAGS, 10PSI MINUMUM PRESSURE MUST BE MAINTAINED" or something very similar.



So if the leveling valve lets all of the air out when you unhook from that big ol' fiver won't the bags be dead empty??? I picture the empty truck happily setting on it's springs with two pruney looking air bags beside them.



Or will the valve keep some air in the bags so that the truck rides like a bobtail spring ride tractor and your teeth keep banging together on every expansion joint???



Or even worse every time the truck bounces empty the air bags try to fill and you recieve a double rebound bounce if you want to call it that.



I read about these on the Air Lift website, checked out the nifty, groovy electric eye leveling valve and all that. I am having trouble seeing the auto level and dump valve feature being all that great when coupled with a spring ride truck versus an in-cab control system.



Now if the truck was full air ride then Hell Yes, I would be first in line. Nothing on the planet any better than full air ride.

Thanks Mike, that was well written and addressed some concerns I have that I couldn't spit out. I was starting to get embarrassed to keep asking questions and yet Bob kept answering them with out loosing patience with me, thanks Bob.



I seem to recall that my Firestone Ride Rites are rated 5,000 lbs per set at 100 psi. If thats the case I would still think that the auto valve would try and level the truck and over come the weight necessary on the springs to control the load. Yet Steve has one of these systems and says it works as intended so there is probably something I am still missing.



Nick

 

[mwilson]

Thanks Mike, that was well written and addressed some concerns I have that I couldn't spit out. I was starting to get embarrassed to keep asking questions and yet Bob kept answering them with out loosing patience with me, thanks Bob.



I seem to recall that my Firestone Ride Rites are rated 5,000 lbs per set at 100 psi. If thats the case I would still think that the auto valve would try and level the truck and over come the weight necessary on the springs to control the load. Yet Steve has one of these systems and says it works as intended so there is probably something I am still missing.



Nick

I could be missing something as well, going to continue to ponder this tonight.



Mike.

 

[Hummin Cummins]

Good discussion goin here. I'll try to catch up since I started this. LOL.



Mike, Very good points. The valve you are talking about is exactly what I plan to use. A rapid response manual leveling valve like class 8 trucks use. Similar to the one on my pete tri-axle. Mount the valve on the bed crossmember and the linkage to the differential cover or axle tube.



I think the point that we are missing is even though the valve is "automatic" All the adjustments for desired ride height are determined by the user upon installation. My old pacbrake bags also had to have a minimum air pressure so in therory, there is always weight on the bags even when the truck is empty. With that said, I dont believe a dump valve would work in this application since the bags require some amount of air pressure even when unloaded, although it would be a nice feature to have.



The linkage that controlls the leveling valve is adjustable. Once the desired ride height is determined (which can be any height that u wish) the linkage is adjusted for that height to be the "neutral" or "off" position of the valve. So once the valve is installed and linkage adjusted to the neutral position with the factory minimum pressure in the bags, when that big ol 5er is unhiched, the valve will release just enough air to return back to the original no load minimum pressure. Will work the same for any load size. From my experience with my old manual fill bags, a level loaded stance and good ride could be achieved with around 50 to 60 psi.



These bags are "overload" bags and nothing more. If they are installed properly, their job is to eliminate sag and porpoising (spell check anyone?) lol. They arent meant to take the full load off the springs.



It should work the same as Steve's system, except that the air is drawn from a tank rather than turning the compressor on and off as needed. Steve, I assume your compressor is dedicated to the airbags and not used for other air needs? Kinda along the same lines as the in cab controls that come as a kit. From what I've read those kits turn the compressor on when you want increased psi in the bags. A true In cab control would work like a tag axle on a dump truck. The system would be charged all the time and u simply turn the regulator to adjust pressure as desired on the fly, making a constant air supply from a tank necessary. That was my original thought in doing this but I'm trying to avoid running a bunch of airlines into the cab.



From Hellwig's website:



For the hands off user offers automatic and instant height adjustment to any change in load condition. The vehicle will always seek its pre-determined ride height. For example if you have preset the Auto Level System to maintain say, a 20inch rear bumper height above ground, as load is applied to the vehicle by placing weight in the vehicle or on the hitch, the bumper will momentarily drop closer to the ground. When the Auto Level height sensing valve receives that input it will begin “airing up” the Hellwig Air spring, thus raising the bumper back to its 20inch above ground preset. In another example, if load is removed from the vehicle and the bumper to ground distance exceeds 20inches the Auto Level height sensing valve will “air down” the Hellwig Air spring adjusting the vehicle back to the 20inch preset. At all times the height sensing valve applies only the needed air pressure to maintain the preset height, thus providing the best ride possible for the load demand.



Maybe this will help muddy things a little

http://www.mediafire.com/file/4ztzwy5zyde/4880.pdf



Chris

 

[mwilson]

I'm getting up to speed now. I think you would still benefit from the dump valve as you would only trip it while unhooking so the bags are deflated which would drop the rear of the truck. As soon as you finish unhooking and drive out from under the pin you turn the valve off and let the leveling system take over again.



Doing so only involves an air source to the flipper valve in the cab and one line back to the shuttle style leveling valve. You could also mount the flipper valve in the body or in a tool box, it does not have to be in the cab. You could flip it just before putting the landing gear down.



Midland KN20001 Valve. I have a nice Freightliner guard that I sell with it. Have redone many air ride trucks that lack a factory dump valve using this little guy and a shuttle style leveling valve

Mike.

 

[Bob4x4]

I doubt if less than 10 psi will raise the truck an appreciable amount, I know mine doesn't