Calling all suspension experts... Sagging leaf springs

cmharmon

Member
I have a 2008 Heartland Sundance 3300 fifth wheel and my leaf springs on the left side (drivers side with kitchen when hooked up to truck) have flattend out causing my camper to sag and lean. I have two 6000lb lippert axles with 4 leaf springs on each axle. I had a service guy upgrade to a five leaf spring and change out all four leaf springs hoping it would beef it up and fix the problem. Well it did not change anything. The new 5 leaf springs on the left side are flattened out also. We are lost and dont know what to do. Is it possible that the new springs were bad? Do I need to go to a 6 leaf spring? I weighed the camper hooked to me truck weighing the camper only on the scales and it only weighed 8400 lbs dry. Do you have any ideas or suggestions? I am desperate. Thanks.
 

danemayer

Well-known member
Hi cmharmon,

I don't know much about springs, but I assume that they have a weight rating, and I don't know that the number of springs necessarily correlates with the weight rating. Do you know if the new 5 spring pack actually has a higher weight rating?
 
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jbeletti

Well-known member
cmharmon,

Unless you are pretty technically minded, this may not be helpful, but here's a bit of info on spring terms, definitions and a calculator.

Like Dan - I'm no expert on springs. I know little about them. But, from your description, it sounds like either bad springs or too low of a load rate for the springs based on the weight you have on that side.

Looking at another popular site, it looks like a 5-leaf spring is about right for your 6k axles. I suggest you you have your trailer weighed, wheel by wheel. Once you know with certainty, what sort of lead you're putting on the suspension and where (wheel by wheel), you can make a better decision on most appropriate springing.

There are a few guys on this forum that have shops and are pretty expert in this area. Perhaps they will see this thread and give you better/more accurate info. In the mean time, please find a place that can do a wheel by wheel weigh.
 

danemayer

Well-known member
If you look at this page, you'll see that for a given number of leaf springs in a pack, the weight rating can vary quite a bit. 6-spring packs for example: one set is rated for 4,500 lbs and another is rated for 7,000 lbs. On this Lippert page, 26" 4-leaf packs range from 1,700 lbs to 3,000 lbs.
 

wdk450

Well-known member
I can't tell you much about your new leaf springs, but I can say that in that 2008 production era poor quality leaf springs was a known problem on this forum, suspected to be caused by poor quality Chinese steel used by the vendors over there to make the springs.
 

Gary521

Well-known member
From some some the sites suggested, you will see that the number of leafs do not indicate load rating. So more leafs don't mean a higher rating or vice versa. Your axle has a load rating tag on it. You can put higher rated springs on a specific rated axle. For example, put 3300 lb spings per side on a 6000 lb axle. This will help a bit but you cannot exceed the axle rating on the overall trailer load. If you are so inclined, changing springs is not a difficult job. This will give you the opportunity to add "wet bolts" to the springs and shackles. Buy US made springs, if you can. I replaced the flattened springs on my 2008 trailer a few years ago.
 

caissiel

Senior Member
I had a similar assomption about my spring on the first year of ownership.
My 7000 # springs were formed in a W and looked overloaded.
Ordered a new set of springs from lippert and compared them. They had exactly the came curves unloaded and loaded as the originals.
Mine are now EMCO certified units for 7000# axles.
The profile for over the axle springs is different as it has to have a flat section for the mount plate. When loaded the flat section curves backward. Even over torqueing the hanger u-bolts creates a load on normal springs without the flats.
I just left it like that and kept the old Springs for spares, instead of returning for credit.

I did have bad experiences with spring plies braking on the previous 5200 lbs axles on SOB unit. So spares to me are important. But in over 25K miles on this they are still hanging on.
But observe often for broken plies within the pack.
A broken ply will usually happen in the middle of the pack in line with the shortest ply. Happened to me most of the time. And a broken main ply will throw the axle out of line.
You can determine broken plies also by observing the tilt of the center equaliser.
I always travel with spare spring in storage and can change one while DW prepares lunch. Happened many times with previous unit.

Sent from my LG-LS720 using Tapatalk
 
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