Metal band on leaf spring

[Guest]

Guest
Hi Jim,

On the topic of spring eyes and bushings . . . after bashing out countless plastic and bronze bushings (often in relatively short mileage) . . . primarily because of the out-of-round spring eye . . . I decided to make my own steel bushings. (I have a metal lathe). I have recently installed these steel bushing on the trailer and we will see how they last.

I think you are on to something with trying to find springs with better formed eyes and bushings.

Rob

Rob,

Nice job on the steel bushings. Eaton presses in a rubber assembly with a steel bushing in a larger spring eye. Wondering if the grease would damage a bushing like that. The spring eyes in what we can currently purchase is not ideal.

Jim

[Lonestar]

Cate&Rob

Rob,

Regarding the bronze bushings on the left, how many miles were you able to put on these before they ended up up in the deteriorated conditioned? I'm sure you lubricated them regularly, and I'll bet many of us have bushings in the same condition and do not realize it. I lube every couple of thousand miles, but really wonder if it helps considering the way they are made.

Also, I assume 90% of the trailers on the road today have worn out plastic bushings or wet bolts with bronze bushings that have never been lubricated. Do the spring ends just eventually wear through?

Jerry

[Jlawles2]

Most of the rubber bushings in springs I have seen use a steel tubular liner for the bolt to go through.

Unless you are using a grease with some strange additive, the Viton or Nitrile used to make the bushing should be compatible.

[Cate&Rob]

Lonestar
Hi Jerry,

The bronze bushing in the picture was one of the worst but still had less than 10,000 miles on it. The primary direction of the spring pressure on the hanger bolt is pushing the bushing into the gap where the spring eye wrap closes back to the spring. When I was changing out springs looking for the right combination to balance my 5th wheel side-to-side, I would find deformed bronze bushings after less than a hundred miles. The bronze is far softer than the non-uniform spring eye surrounding it. I tried the "Never Fail" LCI plastic bushings and they would also get squeezed into the gap at the end of the spring wrap. These are supposed to be run dry and I never cared for that.

If you look at a truck spring bushing, there is an inner and outer steel sleeve with rubber in between. There is enough flex in the rubber to cover the range of motion (which is very little) thus there is no grease required. I could not find anyone making steel bushings for trailer springs . . . so, I had to make my own. They are well greased, of course! We will see how long they last . . .

Rob

[Guest]

Rob,

Another way we could look at this is to obtain a much thicker bushing with bonze inside and supported with a steel outer bushing. I believe the shaft is 1/2 inch? The bushing ID in what we have I believe is 0.58 inch?

Jim

[Jlawles2]

If we could get a good steel outer, then the inner lubricant surface could be polymer or bronze. I think as Rob pointed out, the eye destroys the soft bushings, so his thicker steel bushing may survive because (hopefully) the material he used was stronger than the bronze and polymer that were there before.

Something like a 1018 CR https://matweb.com/search/DataSheet....53e2421&ckck=1 is better than the same material in HR in yield but not ultimate https://matweb.com/search/DataSheet....effebb946995e6

You can then get into the 4140 series and if you get the right one the properties are insane compared to the normal: https://matweb.com/search/DataSheet....f5229afc53bb04

you then get into bronze bearing and the low side is like a play dough compared to the high side that is harder than A36 https://matweb.com/search/DataSheet....5d221c9f604caa vs https://matweb.com/search/DataSheet....33f45d129f7331

At the end of the day, there is no real substitution for thickness for bridging. Thin materials may show to be of adequate strength, but thicker materials can spread the load internally better to help minimize deformations.

[Cate&Rob]

Guest Jlawles2

We are a ways off the original topic of this thread, but to put some numbers to the bushing discussion . . .
It would be ideal to source springs with bigger eyes so that we could install more robust bushings, but that does not seem to be the case for trailer springs.
I have springs under at least three different "brand names" . . . but, they are all manufactured in China.

The spring eyes average 0.685" ID but they are oval with an open gap where the spring wraps back to itself.
The bronze bushings average 0.698" OD with a 0.575" ID. The bolts average about 0.560" diameter.
Thus, the bronze bushing is actually compressed (and deformed) as it is inserted into the spring eye.

The steel bushing that I made are an unknown alloy mild steel tubing (I had to be able to turn ID and OD on the lathe). Machined to match the bronze 0.698" OD and they would not go into the spring eyes without a lot of force. They would not deform as easily as the bronze. I had to turn them down 8 thou further to 0.690" to get a similar feel insertion pressure, using a hydraulic press.

I know . . . more details than anyone needs . . . but might be of use to Jim if he can find a US (or Canadian) source for spring manufacturing.

Rob

[Guest]

Guest Jlawles2

We are a ways off the original topic of this thread, but to put some numbers to the bushing discussion . . .
It would be ideal to source springs with bigger eyes so that we could install more robust bushings, but that does not seem to be the case for trailer springs.
I have springs under at least three different "brand names" . . . but, they are all manufactured in China.

The spring eyes average 0.685" ID but they are oval with an open gap where the spring wraps back to itself.
The bronze bushings average 0.698" OD with a 0.575" ID. The bolts average about 0.560" diameter.
Thus, the bronze bushing is actually compressed (and deformed) as it is inserted into the spring eye.

The steel bushing that I made are an unknown alloy mild steel tubing (I had to be able to turn ID and OD on the lathe). Machined to match the bronze 0.698" OD and they would not go into the spring eyes without a lot of force. They would not deform as easily as the bronze. I had to turn them down 8 thou further to 0.690" to get a similar feel insertion pressure, using a hydraulic press.

I know . . . more details than anyone needs . . . but might be of use to Jim if he can find a US (or Canadian) source for spring manufacturing.

Rob

These dimensions are helpful to provide to Eaton Detroit spring to see if they can bend the spring eye to fit an appropriate bushing. They make custom springs with US sourced steel but their mandrel may or may not be able to accommodate what we need.

Jim

[Lonestar]

This is an interesting topic and I'm enjoying the engineering that's going on here. I wish you guys were at Dexter making all this happen, or at least someone was manufacturing a quality solution.

But, as I asked above, what's going on with the 99% of springs out there with worn out plastic inserts? You hear of a lot of flat spring issues on this and other forums but I haven't heard of any complete failures of spring eyes.