I'll try to load more than one at a time, but is usually will only let me load one at a time. Driving on Tulsa'a main streets. Went over a 1 1/2 inch bump. Snap. Looks like there was a fault in the spring before it broke.
ouch. this is a prime example of the dangers of running monoleafs instead of a leafpack. I hope you and the car are ok.
Typical migrating fracture, small inclusion on the surface allowed a stress concentration or riser and after repeated cycles the fracture begins to migrate until "SNAP".
Nope it's actually what jrBlack30 said.... it opens up a little bit at a time and a little water gets in there and rust it, then it opens a little more and rust a little more... hence the rings like a tree, you can tell it was growing. Glad you're alright doc!
Cars fine. Wife and I both sh*t our pants. We were approaching a bad spot in the street so I had already slowed to about 20mph. Got some paint rubbed off the fender brace on the deuce.
I would bet that if you examined it closer,you will probably find more that just hadn't broke yet! Look for little spec of rust with a small rust colored spider webs moving away from the center, there will be more. This is caused by a number of factors, mostly raw material control and process. Final inspection at the manufacturer should have caught that one, as it started from the surface, simple visual inspection should have caught it.
All steel is cast. Some goes on to get forged, some tempered, etc. The granular structure is affected by these processes, so appearance may change somewhat, but Castings, Forgings, Extrusions and Billet all start out as molten metal poured into some shape or form. Had a customer bring me his car a couple of weeks ago after struggling with very poor handling for some time. It had been in several shops, but it was *** that found and replaced a broken mono-leaf spring. It snapped where most do, right in the center. I've been in many discussions on this and one factor that probably bears consideration is that a mono-leaf isn't flat, yet we clamp it down, with extreme pressure, to a flat surface. The cyclic oscilations on the end of the spring should be more likely to fatigue metal in this cir***stance. A standard spring pack has the advantage that each leaf is shoring up the one next to it, against this fatigue. In my mind, this is the most common cause of a mono-leaf failure, closely followed by examples like the one above. I suspect that building an arched perch seat and clamping spacer would go a long way in adding longevity to the spring's life.
you can tell where the spring fracture started, its interesting to see what looks like rust discoloration in the lines (so it tells me it has been cracking for some time and rusting as it has increased. When I was going to Engineering School to be a Metallurgist, that was some of the best cl***es (fracture ****ysis). would have loved to had that specimen to look under the microscope at. Just can not tell from the picture what the depression is at the orgin (damage, void, weld spark or some other impact.)
It would help if you would list the brand of this spring so others can make an informed decision about their own purchases. Don't worry about "being sued" over that. If you list the brand and show the pictures without lying about the facts, that is perfectly legal and well within your rights.
I had a mono leaf on my 32, switched it out for a multi leaf, much better ride with the multi leaf. Didn't care for the mono leaf. Ago <input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden">
This is a very interesting thread. I hope it continues. If any one thinks that a spring pack solves the problem, think again. For sure a spring pack is more durable in some cases, but they do fail. Case in point, when I took apart my 50 F1 (lots of hard miles)all, accept the smallest spring, were broken in the middle. I would like to hear more about the reasons for mono-leaf failer as Corvette doesn't seem to have any problems, At least not that I know of.
It was discussed already Thus the "RE: Broken Mono-leaf FOLLOW-UP", as shown in the ***le. This is a new thread showing the pics of the spring removed. Read up on his earlier post: http://www.jalopyjournal.com/forum/showthread.php?t=468381
As I said in the other thread, if your spring breaks in the middle, between the Ubolts, it wasn't clamped properly. The center section of a spring is completely dead and unstressed if properly clamped against a solid spring seat. The crack in this spring certainly progressed from a surface defect, but the real issue is that there is no way to properly manage stress in a monoleaf. As I stated on the other thread, a monoleaf gets over stressed and will always fail sooner than a properly designed mulitleaf. Another big advantage of a monoleaf is that it naturally has a progressive spring rate. At small suspension travels, it's relatively soft. As you move it further, and pick up more leafs, it gets stiffer. A mono leaf can't do that. As a result, a monoleaf designed to handle the max suspension load will be very very stiff and result in a really ****py ride. The only way to even come close is to make a tapered leaf mono leaf that tapers down from the middle section the end. It's way easier and cheaper to just use a multileaf. Plus you get the added benefit of being able to design it so that the main leaf is the most protected leaf and the very last leaf to fail. Dan
As the HAMB Metallurgist, I can give you some information Your spring failed by fatigue cracking. The rounded fracture area, called beach marks, is where the crack propagated with each stress cycle. The crack grew a very small amount each suspension flexing, on order of 0.000001-0.00005 of an inch each time. Within those beach marks, there are thousands/hundreds of thousands of very small crack size increase where the crack length grew. Since the crack took time to get that size, it also allowed some corrosion to start. The origin point is where the beach marks converge at the surface. Without more detailed photos and possibly detailed lab ****ysis, I can not tell you exactly what caused that spot to become the crack origin point. That is your root cause for the failure, fatigue cracking is just the mechanism that allowed a crack to initiate and propagate until it became a critical size and then you had overload tensile failure. Most of your fracture surface is tensile overload, looks like lava rock or real rough surface. The leaf spring may have some mechanical indentation or a pit, a surface defect of some sort that led that spot to become a stress concentration where the fatigue crack initiated. Look real close with magnifying gl*** on the surface at the origin point and see if you can find something. No matter what, all it does is let you know why the crack started. That spring definitely had some type of defect that is the root cause, you just have to find it. You might discuss with the manufacturer and see if they will give you a new one and use this for their ****ysis. ***uming they give a **** about product quality and customer service
depends on who made it,someone has been selling Mobile home type transport springs as mono springs they are not designed for the flex of car use,and look just like a auto type just made for different use............
We had one break on the Goodguys Giveaway roadster last year when it was on the big rig traveling between shows. The company would not warranty it. The car had maybe 200 miles on the clock. After that, I will NEVER use a monoleaf.
This is true. I snapped the main leaf in the rear leaf pack under a 32 coupe; however, the spring clamps held the leaf pack together. The back end of the car ended up way off canter which made us look at the leaf pack. As I told my Dad, this occurred under "normal" driving.
Thanks for the great answers guys. Now what we need is a qualified answer on the durability of the Corvette type mono spring. Perhaps that is what we need developed for the hot rod scene.
SURPRISE! The composite front spring was developed for 28-34 Fords by HAMBer Andy from Kerrville TX quite some years ago. It has supported his roadster up front for quite a few years now.
In 1984 We raced the then new Corvette C4 in IMSA road racing. At a 24 hour event a bunch of the cars, including ours, broke the exhaust off right at the diff. Soon after all the cars started breaking the composite mono leaf spring. We broke 3 of them on about 8 hours worth of racing.
The Corvette spring is fibergl*** and is made by a company called Liteflex. Although it is also a transverse leaf, like an early Ford, it is not used as a suspension control member. If it breaks, the SLA susupension just falls down onto the jounce bumper. Dan
First let me say we use the mono leaf spring but I have replaced five (5) mono leaf front springs two (2) were on my own 32 roadsters . Three of the springs broke through the tie bolt hole, one broke outside of the clamp and one broke half way between the clamp and the eye.the two that broke outside of the clamp were on the p***enger side of the car. Two of the springs were chromed and the other three were painted. They all had that spot on the bottom side of the spring where the break was. They do not warrant the springs from breaking and say that it has never happened. The one that broke on my wife's car broke in the tie bolt hole and it was chromed and after it broke she was able to drive it about a 1000 miles home . Her spring had about 65,000 miles on it. Bruce
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