Rear Air Bags and Height Adjustment

[John Jensen]

Here are my notes for adjusting the heights. Aftermarket adjustable links:

2014-2023+ RAM 2500/3500 Adjustable Air Suspension Links For Lifting

These easy-to-install kits quickly replace the stock rear sensor arms to Billet Aluminum Fully Adjustable Sensor Links. With these links you can safely adjust the stock ride height by up to 2.5

www.revelperformance.com

 

[18CrewDually]

Here are my notes for adjusting the heights. Aftermarket adjustable links:

2014-2023+ RAM 2500/3500 Adjustable Air Suspension Links For Lifting

These easy-to-install kits quickly replace the stock rear sensor arms to Billet Aluminum Fully Adjustable Sensor Links. With these links you can safely adjust the stock ride height by up to 2.5

www.revelperformance.com

View attachment 546542

Thanks John. They are the links we got for my father's truck. I couldn't remember to post the link.

 

[BLUKTY2]

Have you checked for broken springs? Could have a broken front spring causing the rear on that side to carry more weight. Or a broken leaf in the rear spring pack.

Good thought. I had not but just did earlier today. All look good.

That above I posted is the app on my android phone. If you notice, I selected 3500. It is specific to the rear only air springs which is what you have.
You can see it here in this screen shot, it refers to the rear only.
View attachment 546533

I finally got to where I needed to be in AlfaOBD. Thank you! I really appreciate you taking the time to get me moving in the right direction.

I first conducted a Compressor Circuit Test which completed successfully. This test sets a code (C2212) but the AlfaOBD software warns you that this would happen and to just clear the code. I had some trouble clearing this code but finally succeeded after a couple of tries.

I then tried to do the Component Air Mass/Pressure/Ride Height Readings. I got a prompt that says "Started. Please wait...". I initiated this test three times and waited up to about 10 minutes with no readings appearing. Not sure what to think of this one. Wait longer? This attempt also set the same code each time I tried it but the software does not warn you about this unlike the Compressor Circuit Test. Maybe this indicates a fault in the system?

I have not tried to do a manual fill because I would like to know what the pressure of the individual bags are first. I will keep trying to get these readings but I ran out of time today. If this test keeps failing with AlfaOBD I think that my Autel scanner can show me this information.

Here are my notes for adjusting the heights. Aftermarket adjustable links:

2014-2023+ RAM 2500/3500 Adjustable Air Suspension Links For Lifting

These easy-to-install kits quickly replace the stock rear sensor arms to Billet Aluminum Fully Adjustable Sensor Links. With these links you can safely adjust the stock ride height by up to 2.5

www.revelperformance.com

View attachment 546542

This is great information- thank you John! I am going to order a pair of these links as soon as I am done posting this.

I don't think that I will have much time in the near future to continue to pursue this issue any further but I will report back with any new findings as they develop.

THANKS for all of the help and ideas gang! Great bunch of folks on this forum.

 

[BLUKTY2]

Another update- here are some of the readings that I got on an Autel scanner and my take on what they mean. Please correct me if I am misinterpreting these readings:

These two photos show the value (in inches?) of the left side versus the right side. Higher on the left than the right which is what I am finding with a tape measurer, measuring from the ground to the top of the wheel well arch on level pavement. At the time these readings were taken the truck bed has probably 150#'s of weight in it. By my measurements, the right side sits about 1/2" lower than the left. This increases to about an inch with a heavy load in the bed. Note that Level Calibration has been completed so the module "thinks" that the truck sits level but it is not.



This photo shows that the pressure is identical in both air bags.



My plan at this time is to replace the factory linkages with the adjustable linkages from Revel Performance; these are going to arrive this Friday. I will slowly increase the length of the right link and will expect to see an increase in the psi of the right bag and an increase in height of the right side.

As always, any other thoughts/advise is welcomed and greatly appreciated.

 

[18CrewDually]

Now you're getting somewhere. When we put the links on my father's 2018 DRW I remember it being sensitive. In other words make small changes until you get it where you want it. Like 1 or 2 turns at a time and drive it in between changes to see where it settles out.

 

[BLUKTY2]

Now you're getting somewhere. When we put the links on my father's 2018 DRW I remember it being sensitive. In other words make small changes until you get it where you want it. Like 1 or 2 turns at a time and drive it in between changes to see where it settles out.

I will definitely make small changes and monitor the system after each change. I just got notified that the links will be arriving today instead of tomorrow, and I am anxious to get them installed. The real test will be when I get the camper loaded back onto the truck, which will probably be a few weeks. I will continue to provide updates on my progress.

Thank you for your continued advise and recommendations!

 

[DA67Goatman]

I'm glad you stuck with it and are showing your solutions. Thank you, keep it up.

 

[BLUKTY2]

Latest update. I was finally able to empty the truck bed and observe the live data with no weight in the bed. This is what was shown:



This is with the factory links, empty bed on level pavement. By my tape measurement, the right side was lower than the left by about 1/4". My previous tape measurements, from about 8 months ago, showed the right side lower than the left by about 1/2" with the bed empty. So I'm not sure what to think about that, but I guess that a 1/4 inch difference is not a big deal and I can live with it.

I left the factory link attached to the left side and attached the adjustable link to the right side. After a little adjusting to lengthen the right link, I got the bed level according to my tape measurements. This is what was shown on the live data:



So the left side dropped down a bit (without any adjustment on that side) and the right side went up a fair amount. The bed is level to probably within 1/8" according to my measurements at this point. The real test for me will be then I load up the heavy camper.

I will report back once I get the camper loaded and play around with the adjustable link.

 

[18CrewDually]

Sounds good. And same issue & results we had after getting the adjustable links.
Questions though. Are you letting the truck calibrate with you in the driver seat? And how much fuel in the tank? 1/2 tank?
I ask because both driver and 32 gallon fuel tank is on the left side and may be considered.
The real test is with the slip in camper unit in the bed of course. And loaded with fresh water.

 

[BLUKTY2]

Sounds good. And same issue & results we had after getting the adjustable links.
Questions though. Are you letting the truck calibrate with you in the driver seat? And how much fuel in the tank? 1/2 tank?
I ask because both driver and 32 gallon fuel tank is on the left side and may be considered.
The real test is with the slip in camper unit in the bed of course. And loaded with fresh water.

Very good questions and both something that I had not thought of. Yes, I am in the drivers seat and the fuel tank is 3/4 full. Definitely two points to keep in mind.

The bottom line is at this point I am pleased with the results and I am convinced that I am on the right path. Thank you for the continued input and advise! I will report back once I get the camper loaded and the bed leveled.

 

[BLUKTY2]

Here is another update on my progress. My camper is finally loaded onto the truck and I have been making small adjustments to the right side link, measuring the height of both sides with a tape measurer (ground to top of rear wheel well) and occasionally monitoring the live data of the air bag system. After each adjustment of the link I drove the truck for several miles and rechecked the height measurements of each side before making another adjustment. I also cycled the system between the Alternate Trailer Height and Normal Ride Height several times.

My initial goal was to level the bed of the truck from the 1" difference that I had to 1/2" or less. By my measurements I am now within 1/4-3/8", with the right side still lower than the left. Honestly, the following photos of the live data are inconclusive as I did not check this data with the original link in place on the right side with the camper loaded on the truck. So I don't have a "before" and "after" comparison of these readings with a heavy load in the bed, just with no weight in the bed.

While I am overall happy with the results, I am surprised at some of my findings/readings as I slowly lengthened the right link. Just to reiterate, I leveled the bed by extending the right link slightly before loading the camper (see post #28).

1. I am surprised at how far I had to extend the link to raise the right side 5/8-3/4 of an inch. According to the link instructions from Revel Performance, two turns should result in about 1/4" change in height; so 8 turns should result in about a 1"change. I made the mistake of not keeping track of how many turns I made to the link to lengthen it, but I lengthened it no less than 12 turns, probably closer to 15 or 16.

2. As I lengthened the right link the left side height increased as well, but not as quickly. All told it rose 1/4", which wasn't helping me achieve my goal.

3. As I lengthened the link, I expected to see a difference in pressure between the two air bags, with the right side slowly gaining a higher psi reading than the left as I made adjustments. This did not happen as the photos show.

Here is the live data after my final adjustment. These reading are with me in the drivers seat (185#'s) and 1/2 tank of gas:




System pressure in Alternate Trailer Height:



It is easy to see the difference between the left and right sensor arms after my adjustments. Left on the left, right on the right:



While certainly a good improvement, and within the goal that I was hoping for, I am surprised that the right side isn't much higher than the left by now considering how much I lengthened the right link. I suppose that I should probably call this good and move on with my life, but I cannot help but wonder if I can do better. Perhaps replace the factory link on the left side with my other adjustable link and start shortening it? IDK.

Unless someone has any other thoughts or advise I think that at this point I will drive the truck/camper around for a few hundred miles or so while occasionally monitoring the height of both sides for any signs of change. I will continue to post updates if I make any further adjustments.

Thanks again to all that have contributed to this post! I wouldn't be where I am now without your help.

 

[18CrewDually]

I would definitely consider it within a close enough range to leave it alone and see how it does over a period of time.
On my father's truck, we had the set it and forget it mentality unless it started to show a noticeable difference again. It has to be 3 or so maybe 4 years by now and it is still good.

 

[BLUKTY2]

I would definitely consider it within a close enough range to leave it alone and see how it does over a period of time.
On my father's truck, we had the set it and forget it mentality unless it started to show a noticeable difference again. It has to be 3 or so maybe 4 years by now and it is still good.

Thank you sir! Really appreciate all of your help!

 

[danielfastv6]

BLUKTY2, did you ever check each bag itself? I have a similar problem with my 21 3500. My driver side bag is hard/firm to the touch, while my passenger bag is much softer.

 

[BLUKTY2]

BLUKTY2, did you ever check each bag itself? I have a similar problem with my 21 3500. My driver side bag is hard/firm to the touch, while my passenger bag is much softer.

I did not. I just monitored the air bag data on the scanner.

 

[GodSpeed]

This thread is a year old so I won't rehash things that already seem to be resolved, but I too have a 2017 3500 SRW and have some questions for the OP or anyone with the same truck. Interestingly, it is VERY difficult to find info online on the 3500 air bag system. Everything seems geared towards the 1500 & 2500 systems which is very different. I happed to stumble upon this forum and thread by searching for info on the Revel rods as I have just about given up on the dealers.

- What gap do you have between your overload pads on the bottom leaf and the next leaf up when unloaded? My right rear is touching and I've had the truck at two different dealers and calibrated a million times with no faults, no external leaks, air compressor assembly (includes manifold) replaced... I'm having a heck of a time getting them to comprehend that this indicates there's an issue which I simply believe has to do with their calibration process and that very precise calibration is required at setting NRH to begin with. If they're not careful and precise with their initial measurements, all subsequent modes/heights/etc. are based off this incorrect initial NRH. Very frustrating. What I find additionally frustrating is that the OEM specs allow for a 1-5/8" (*286.2mm to 326.2mm with the target being 296.2mm) range variance to be within spec. *The techCONNECT (dealer tech software system) procedure to take this measurement is to measure A - from ground to center of wheel hub, B - from ground to a specifically prescribed spot on the frame (either 3" or 5", depending on wheelbase, forward of a hole at the rear of the frame, kind of beside the spare tire but rearward of the rear leaf spring perch) and then subtract A from B...again, targeting 296.2mm or roughly 11 11/16". I don't like that to begin with, but particularly if there's a variance that large between Left and Right but it's still deemed "within spec" and will pass all calibration procedures.

- With an AlphaOBD, can you command fill individual bags? Can you then recalibrate NRH and tell it, "this is NRH" ? By the sounds of the discussion and screen shots it appears you could, but then the OP and others with AlphaOBD would not have to use the Revel rods as the solution; why not just use the software to make L/R ride height adjustments?

 

[BLUKTY2]

I am unable to provide you with any gap measurements at the current time as my truck is at a dealership waiting for a new transmission. Probably won't have it back for at least a couple more weeks. Perhaps someone else will chime in.

As for using AlphaOBD to control individual bags, I have no idea if this is possible, but it certainly is an interesting thought and probably worth pursuing. Doesn't seem like you would have much to loose except some time. I have AlphaOBD but never tried using it to resolve my height issue. If you do pursue this, I would really appreciate a follow-up report.