Shocks help

[spconway]

We have a 2009 PW PLAT TS with Dualies, less than 20,000. The rear bounces so much over any bump that our dogs ( 90 pounds) go 8 inches in the air with each bump and I can not sit in the rear. We will sell if we can't find a solution.

1.KONI. Called PW and they recommended $800 Koni shocks. Installed _NO DIFFERENCE.
2. Adjusted air Pres in tires to run 75 PSI rear and 50 PSI front as per PW- NO DIFFERENCE.

Help my frustration level is high. Anyone who has a solution please let me know. I have thought about Air Shocks but know nothing. We love our PW but it is not making it and we are going to an airstream trailer pulled by our SUV if no answer to this problem.

Steve

[Mat Mobile]

Look on the bright side! Free dog trampoline!

Seriously though, I'm wondering if the stock springs from a Dually 1 ton Sprinter are over-built for an RV.

I'm in the process of lifting my van. So I had custom springs made to the exact weight of the van. This meant weighing the van and each axle. I was suprised at how light it was (but it does have a fiberglass body). My rear leaf springs ended up having more leafs but I suspect they are thinner. Disclaimer: I've only tried it once (it's still in the shop) but the ride was MUCH better.

Basically, springs hold up the weight of the vehicle and allow it to bounce. Shocks prevent the bouncing from "cycling".

So maybe the issue is that the spring rate in the back is too high?

I hope you don't have to go out and purchase another leaf pack... But maybe it's worth getting the weight of the van and each axle and asking a few spring experts. I will also suggest asking Van Compass as they know Sprinter suspensions very well and have done improvements on other RVs like yours.

[spconway]

Mat
Thanks, Good thoughts . I would not be surprised about the leaf springs. I will look into that. I have heard from Van Compass and AgileOffroad. Both guys make custom shocks for Sprinters and I am discussing it all with them too.
Steve

[booster]

The big thing with springs, both front and rear, in cargo vans is not that they are necessarily to high a rate, it is that they are way to progressive. They have to be to be able to handle being an empty van or a van running at max gross weight. As they approach the gross weight area, they get into and area of the spring that is very high rate and often a huge overload leaf that will actually slap the rest of spring pack on bumps.

The hard part, I think, is that most of the aftermarket spring guys make there spring also quite progressive, and start stiffer besides, so they can get very stiff. It may be quite hard to get a multileaf spring pack not to be progressive, but I don't know that for sure.

The newer Sprinters can switch to air ride, which by all accounts is much smoother, but expensive to buy. On our Chevy, we went half and half with air and springs. We put in airbags with internal bump stops and took out the big overload leaf in the springpack. We carry about 1/2 the weight on the bags and half on the much less progressive and stiff remaining leafs in the springpacks. Our ride got very much smoother and quieter with this setup.

[spconway]

Booster,
Thanks for info. What Air Bag did you buy?

[InterBlog]

I did a lot of research on this issue in October of 2017. If I were in your position and I did not want to mess with a DIY job, I'd go to Utility Bodywerks in Elkhart IN and I'd get them to do a VB air suspension retrofit for me. I talked to a guy named Jeff Whitlow there, and he quoted me $5,500 for the kit and $895 for labor, *unless* there was something about my van that would make the installation more difficult and drive up the labor cost somewhat.

Unfortunately the VB system could not be retrofit to a T1N Sprinter, as it was really designed for an NCV3, so I did not pursue this. But I would have, if it had proven feasible.

VB will not sell direct (I tried that approach first, thinking that perhaps DH and I could retrofit ourselves).

[booster]

Originally Posted by spconway

Booster,
Thanks for info. What Air Bag did you buy?

We used Airlift bags, but I don't think there are any add on air bags for Spinters, so not something off the shelf for you I think.

Switching to the VB system would be by far the best, but expensive. Pure air ride gives a very smooth ride, although can be a bit "floaty" for some tastes. Most really like it.

[booster]

I take that back, there are aftermarket bags for Sprinters.

https://www.sprinterstore.com/produc...-models-2-bag/

This might make it so you could go to lighter springs and put the weight on the airbags to get a smoother ride. Just be sure you have good bump/overload stops in case you have a bag failure, which is very rare, but happens.

Here is an interesting add on that is claimed to smooth out ride when used in conjunction with the stock springs.

https://kelderman.com/shop/2014-spri...air-suspension

[Boxster1971]

Originally Posted by booster

I take that back, there are aftermarket bags for Sprinters.

https://www.sprinterstore.com/produc...-models-2-bag/

This might make it so you could go to lighter springs and put the weight on the airbags to get a smoother ride. Just be sure you have good bump/overload stops in case you have a bag failure, which is very rare, but happen....

Those Boss airbags from the Sprinter Store are not a good idea for Sprinters. They are from Australia and like the US kits like AirLift and Firestone they can lead to severe frame damage. The Sprinter vans are unibody and the frame rails under the van are not designed for constant point loads like these kits make. There is an infamous thread on the Sprinter-Source forum that discusses the issue in great depth after a plumber overloaded his van with the Firestone Airbag kit. Shortly after the full story posted both Firestone and AirLift dropped their Sprinter kits.

There is only one add-on Airbag kit that will work safely on a Sprinter. It is made by Dunlop and not currently sold in the USA. I got mine from a U.K. dealer. The full story of my install is at this link on the Airforum.
http://www.airforums.com/forums/f240...on-158957.html

- - Mike
2012 Sprinter 3500 Extended converted B-Van by Airstream

[booster]

Interesting about the frame damage. There have always been claims of that with the other brands of vans, too, but they never quit making the bags.

Do you have any experience with the style of bags in the second link in my earlier post, that mount at the rear spring shackle instead of the middle of the axle?

[Boxster1971]

Originally Posted by booster

Interesting about the frame damage. There have always been claims of that with the other brands of vans, too, but they never quit making the bags.

Do you have any experience with the style of bags in the second link in my earlier post, that mount at the rear spring shackle instead of the middle of the axle?

I have no personal experience with the Kelderman air suspension, but it is a lot like the VB air suspension, more a full air suspension system. I have read several good reviews by Sprinter owners who had the Kelderman system installed. Both the VB and Kelderman systems are a good solution for Sprinters. The old negative is they require about 12-15" of free space behind the rear axle to allow the installation of all the required components.

There is another option for Sprinters, the Glide-Rite air suspension from the U.K. It is available from several shops in the USA, and from the Sprinter Store.
https://www.sprinterstore.com/produc...-system-4-bag/

There are also systems from Europe, Italy for one has a kit that is mentioned near the end of my AirForum thread posted above. But they are probably more difficult to option in the USA.


- - Mike
2012 Sprinter 3500 Extended converted B-Van by Airstream

[Boxster1971]

In case anyone wants to read the full story on the Sprinter-Source forum about frame damage from a Firestone Airbag kit here is link to the 16 page thread that was stared 9 years ago.
https://sprinter-source.com/forum/showthread.php?t=4622

The plumber who started the thread likely overloaded his 2500 model Sprinter. I'd imagine if you kept the load within limits and the pressure in bags in 40 psi range you could avoid frame damage.


- - Mike
2012 Sprinter 3500 Extended converted B-Van by Airstream