Need to beef up rear suspension on 08 Expy EL

[The Sod Father]

I have a 2008 Expy EL Limited and need to beef up the rear suspension. I tow a 7,500 lb camper with about 800 lbs of tongue weight. I use a weight distribution hitch and it helps transfer the weight but I still get some sag. If I crank up the WDH too tight, I get porpoising. Plus the soft suspension is not ideal for this type of towing.

I've scoured the web for air bags but they do not exist for the gen 3 Expy. At least not that I could find. My other option is to get stiffer springs but have not found a source or know if this is even an option.

Any suggestions?

 

[Johnnie Parker]

Following.

 

[Grrumpy]

Unfortunately with an independent rear suspension there isn't too much you can do. No air bag set up's are available.
There is a Sumo rear coil spring insert that may stiffen it up a bit, but the best fix would be to go to a pair of new heavier duty rear spring/strut assemblies from KYB or Bilstein.
My 2019 has the same basic suspension and I tow a 7000 lb camper with a 750 tongue weight, so I am well aware, after much researching, of what is available.
Some here advocate for a heavier rear sway bar, which while will give you better handling when solo or towing, will not do anything to "stiffen" your Expy while running in a straight line.
From what I have read here, if you have the load leveling suspension there is even less you may be able to do.

 

[BigOleFordFan]

I've scoured the web for air bags but they do not exist for the gen 3 Expy.

So, are these "Air bags" that you seek different from the "Air Ride System" that came stock on the rear of many '011 EL's (like mine) ?

I don't know for sure, but as I understand it, that system functions like a continuously variable, electronically-controlled set of air bags/shocks that adds pressure when a load above normal levels is detected, and returns to normal when the load is reduced or removed..thereby ensuring that the ride comfort stays constant and that the suspension can't bottom out.. perhaps that's where the "load-leveling" part comes in to play...

Unfortunately with an independent rear suspension there isn't too much you can do. No air bag set up's are available.

So based on this statement, apparently my truck does NOT have an independent rear suspension ?