Softening the Suspension on an M101CDN Trailer

[k294]

Bumping this back to the top because I am trying to follow along...

I would like to replace the gnarly/rusty/generally-too-rough stock springs on my cdn m101 with more progressive units. Sounds like these OME/Dakar Leaf Springs (CS013FA) and the slightly lighter duty CS012FA are the way to go? With new bushings of course.

Anyone who's used these-- how was the swap? Fairly straightforward, or was there some fabbing/modding that needed to happen?

I'm looking for the least amount of hassle possible.

Edit: found another source for the springs/kits if indeed these will work: http://www.lowrangeoffroad.com/inde...ion-parts/old-man-emu-dakar-leaf-springs.html

 

[AA1PR]

I didnt read every post

but from what I have seen in the past if you remove too many springs..

that the springs often break where there is no support underneath them

think of them as a foundation that flattens out when under load & flexing, when they collaspe the one underneath supports it

if you remove one long one & leave too short of a one, the longer spring basically tries to flex down past the supporting one & breaks at the fulcrum point

hope this helps

 

[shakotankei]

Anyone need an old set of leaf springs?

 

[Expedition.Report]

I am interested in what you guys found out as well, for now I am going to try and run lower tire pressure in the trailer wheels to see if that helps

 

[BrettDez]

Anyone actually have success with this? My stock springs have gone flat so they need to be replaced now.

I don't want to go too soft which is a fear of mine.

 

[workingonit71]

alternative to standard springs/shocks for progressive spring support?

in-between my axle and frame

...but from what I have seen in the past if you remove too many springs..

that the springs often break where there is no support underneath them

think of them as a foundation that flattens out when under load & flexing, when they collapse the one underneath supports it

if you remove one long one & leave too short of a one, the longer spring basically tries to flex down past the supporting one & breaks at the fulcrum point....

The quote above was the focal point of my recent trailer suspension re-build (its not a M101CDN, though my trailer is rather heavy at 1600-1800 lbs-trying new configurations-; maybe comparing apples to oranges?). Since I feared having my springs flatten-out, if over-flexed, breaking the spring (broke one on my car-hauler), and/or causing a hanger to tear off the frame at that point (happened once on my little trailer, spurring my alternative approach), I put a bump stop e to stop those mishaps from happening again. However, I wanted to have a progressive response from the bump stop, before the limit of travel is reached. The axle (on my "being modified for soft-roading" trailer) has only 1.125" of travel from normal ride height to suspension at full droop, so I thought that the use of standard shock absorbers would not be beneficial, and opted for a non-standard approach: a progressive bump stop to serve both functions. It acts like a hollow air spring (like a Timbren Aeon $$$, Sumo, or like found on the old Ford Model A shocks -"balls"-, and similar on several older European models). I modified it to fit, and softened its "rate" (by removing the hard/stiff top). I had experience using poly bump stops on several of my trucks, and thought that the Daystar "progressive" would need little mods to fill my needs. I've tested it, in actual on-road use, and "simulated off-road" terrain (pot-holes, speedbumps, whoop-de-doos), and it does well. I can even soften the rate more, if I choose to. If you, the OP, want to use "soft-er" springs on your M101CDN, but wish to avoid the consequences of over-flexing under over-loading or rough impact, consider this approach (or similar).

• Daystar 4.5" progressive stop
• modified, welded to angle 2x2x.25
• loaded trailer, stop in slight compression

 

[M35A2]

I just happened across this thread. While I am an advocate for doing things oneself, perhaps also categorize your use case. Do you have plenty of time to experiment and try different things, and if something fails are you close to home? Or will you load up and be gone without a convenient opportunity for rework?

If the latter, in my experience you are far better off bringing the springs to a spring shop. Tell them what you want and they will know what to do. They can even re-arch and heat treat the packs as needed.

Someone said you can get into trouble just by removing leaves because if the remaining leaves are not properly supported it could eventually cause a problem. Totally true.

There is even more than that. You might soften the ride but cause the spring to react not as linearly as before. That can get annoying when a certain load and a certain bump at a certain speed gets the trailer hopping as it did before.

Finally, as you remove leaves you change the ride height, and OP noted that it was perfect at the outset.

Telling the spring shop that you want a softer ride with the same ride height and load capacity of X (most probably less than what the Army needed) and for a surprisingly affordable fee will get you on the road without a science experiment (or fighting the center bolt when it flies apart or to get the spring back together).

My .02.

 

[Septu]

I am interested in what you guys found out as well, for now I am going to try and run lower tire pressure in the trailer wheels to see if that helps

That's all I've done (have been riding ~20 lbs for the last 2 summers - although barely put any miles on this summer). Kinda works, but I don't think it's a perfect solution. And I wouldn't want to go too much lower.

 

[java]

That's all I've done (have been riding ~20 lbs for the last 2 summers - although barely put any miles on this summer). Kinda works, but I don't think it's a perfect solution. And I wouldn't want to go too much lower.

Depends on the load. My tires are at about 12 psi iirc, and the sidewalls look normal. My trailer is probably about 1k lbs loaded. Look at the weight to pressure rating on the tires, as an example, say they will hold 3500lbs at 40psi. Your tires don't need nearly that much air to hold a 2000lb trailer. so in theory for a 2k lb trailer you would only need 22 psi, and the load is split on the tires, so 11 each.

I just make sure the sidewalls look normal, and the treads are pretty easy to see if they are under or over inflated. After a dusty road, onto pavement, you can see really easy how the tread is wearing on the road.

 

[brentbba]

Anyone need an old set of leaf springs?

Shakotankei just did this conversion to the OME's. He'll have to chime in on the ride. Quick shake test on both his and my trailer showed a much more flexible response on his. Mine obviously much, much more stiff with the original military leaf springs than his new set up.

 

[BrettDez]

Thank you for the update guys, do you know the exact part numbers that were used for the OME conversion? Did you use the HD leaf?

 

[ezzzzzzz]

I didn't bother reading through this thread. I have restored/modified a M101cdn trailer for my use. The stock leaf spring packs were disassembled, sandblasted, primed, painted and reassembled using poly slider material between each leaf. The shackle bolts were rifle drilled and cross drilled to allow for lubing with a grease gun. It rides very nice unladened or ladened.

 

[j_colter]

Any updates on the ride of the OME conversion springs?

Cheers,
Jeff

 

[j_colter]

Beware of the recommended CS012FA-CS013FA for a heavy M101cdn

I have a 2000 lbs m101cdn. It has the following setup
-Steel lid (I believe 100lbs or more)
-RTT
-Tongue box with batteries
-40L water tank between tongue box and trailer box
-Two propane tanks 20 lbs and 10lbs in trailer
-Extended tounge
-Camping gear pretty much fills the tub box
-Roll out awning, side mounted on poles

The CS013FA (heavy duty samurai springs) were not heavy duty enough for my trailer as I installed one and the leaf basically flattened out. I currently have the new springs in with a spring shop to have two more leaves made to add to the leaf pack, gonna cost $160 per leaf Will update with more info once I get the upgraded leafs installed.

Cheers,
Jeff

 

[yj4trails]

Might want to look at Rancho 2.5 lift springs for the front of a cj3a. They are exact same length as stock and use similar bushings.