Broken leaf springs - third time!

[solismaris]

My 2005 Prowler trailer has just had its third case of broken leaf springs. The first occured just 2 years after purchase, and the second 5 years after that. That set lasted a while longer: 7 years; maybe because I took it to a specialty shop and had them put on "extra heavy duty" springs".

Not good enough. Why do they keep breaking? I inspected the damage: The leaf just broke in half close to where it attaches to the frame. The metal doesn't appear to be corroded badly: surface rust but the inside metal looks shiny.

The design seems strange: Though there are several layers of leaves through the center (4 I think) it diminishes to a single leaf at the attachment. That seems like a weak spot. And indeed that's where the break occurred all three times. Is that a normal design?

I'd love to find a fix for this. I know it's an old trailer but is 2-7 years really the longest I can expect before a failure? This is the worst kind of breakdown because it comes without warning and can cause major problems if it happens far from home. Amazingly, the last failure happened 100 feet from my driveway! So all I lost was 4 days camping reservations 😞

Trailer GVW is 8000 pounds and I do not have it heavily loaded with gear or supplies.

[time2roll]

Assuming the 5000 to 6000 is the rating for the pair... I think 5000/5200 will be plenty. I believe that is what I have on my 3500 axles and it rides great.
I have the wet bolts but no shocks.

[myredracer]

Lynnmor wrote:

solismaris wrote:
Would there be a problem installing springs rated for 5000 or even 6000#? The shop is willing to do that if I want.

A much higher spring rate than required will cause a much harder ride. Since you are getting it weighed, you will know the minimum spring rate needed and then go higher using your best judgement in just how stiff is acceptable. Going to nearly double would be way too much.

Stock OEM spring rating on our TT model is 3500 lbs. The factory put 5200 lb springs on in place of 3500. Also have shocks and wet bolt kit on it. It bounces a LOT less and handling is better. No issues after 5 years and over 20K miles. No downside that I can see.

[Ron3rd]

The spring shop can also install bronze bushings allowing you to run "wet bolts" with a zerk fitting to grease the bushings, thus eliminating the junk plastic bushings that go away quickly and fall out when you remove the spring.

[Ron3rd]

See if these show up:

The photos below show how to make a spring that will never break.







The above photos show how to make a spring that will never break.

[Ron3rd]

solismaris wrote:
My 2005 Prowler trailer has just had its third case of broken leaf springs. The first occured just 2 years after purchase, and the second 5 years after that. That set lasted a while longer: 7 years; maybe because I took it to a specialty shop and had them put on "extra heavy duty" springs".

Not good enough. Why do they keep breaking? I inspected the damage: The leaf just broke in half close to where it attaches to the frame. The metal doesn't appear to be corroded badly: surface rust but the inside metal looks shiny.

The design seems strange: Though there are several layers of leaves through the center (4 I think) it diminishes to a single leaf at the attachment. That seems like a weak spot. And indeed that's where the break occurred all three times. Is that a normal design?

I'd love to find a fix for this. I know it's an old trailer but is 2-7 years really the longest I can expect before a failure? This is the worst kind of breakdown because it comes without warning and can cause major problems if it happens far from home. Amazingly, the last failure happened 100 feet from my driveway! So all I lost was 4 days camping reservations 😞

Trailer GVW is 8000 pounds and I do not have it heavily loaded with gear or supplies.

Had the same problem and the fix is have a real spring shop make you a set of springs. Most trailers come with cheap $39 China junk springs. A good custom made spring is about $100.

My local spring guy explained why they break at the eye almost every time. In fact, he told me where it broke when we were on the phone. He was right. He makes the second leaf below the top leaf longer to wrap under the eye. I have some pictures somewhere and will post them when I find them

[solismaris]

trailer_newbe wrote:
Is it always breaking the same spring on the same side?

No; last break was on the opposite side. But all 3 breaks were a clean break across the single leaf a couple inches from where it curls around the bearing, before where it joins the bundle of 2, then 3 leaves.

[trailer_newbe]

Is it always breaking the same spring on the same side?

[Boband4]

I had the clamp that encircles the multiple layers of the springpack break. This allowed the springpack leaves to spin out from each other. This meant all of the weight was carried by one leaf versus 4. Definately overloaded that one and caused it to break. I replaced the clamp with a worm drive hose clamp and it has been fine.

[Lynnmor]

solismaris wrote:
Would there be a problem installing springs rated for 5000 or even 6000#? The shop is willing to do that if I want.

A much higher spring rate than required will cause a much harder ride. Since you are getting it weighed, you will know the minimum spring rate needed and then go higher using your best judgement in just how stiff is acceptable. Going to nearly double would be way too much.

[dodge_guy]

I’ve never had a broken spring in 16 years. 14 of those with the same trailer! However mine was never overloaded, not even close. It was weighed and I was always 2k lbs under its GVWR. The other thing was the springs weren’t tapered like yours. Mine the leaves were longer and stopped about a 1/3 of the way from the spring eye.

I think it’s the style of spring you have!

[solismaris]

I will have it weighed. I don't believe it's overloaded but will find out.

The mechanism looks correct (nothing inverted).

There was no sag observed before the spring broke, and there is no sag on the other, unbroken side.

I think the biggest issue may be bad steel. Especially with the data point of the 26yo trailer with original springs that was just posted.

I have 3500# axles. Would there be a problem installing springs rated for 5000 or even 6000#? The shop is willing to do that if I want.

[Lynnmor]

CavemanCharlie wrote:
My TT is 26 years old and has not broken any springs yet.

Might it be from a time that better steel was used?

[CavemanCharlie]

My TT is 26 years old and has not broken any springs yet.

I bought it used about 6 years ago and I don't pull it far. I don't know how far the original owner pulled it. But, it has enough miles on it that the holes in the center section where the springs attach to the equalizer are starting to get elongated slightly. No broken springs though.

[valhalla360]

Take it to a scale when loaded for travel and see what the real weights are.

Yes, springs break but it's not common.

[JIMNLIN]

Is a 'center equalizer' flipped.....look same as other

I've broken springs on a equipment trailers that the equalizer links had flipped on one side.

On another used cargo trailer I had to buy when on the road some moron installed longer equalizer bars.....result was busted top leaf on curb side and cracked two leafs on the trailing axle same side. I was on the road so stopped at a large PJ trailer dealer in west TX. His tech found the problem quick and had me back on the road in just over a hour.