I think you're right, though I would note that early ('62-'65) 6 cylinder Chevy Novas used steel monoleaf springs on the rear. They are unlikely to fail in that application because they are on the rear of a lightweight car. Monoleaf springs on the front end of an old Ford with a single transverse spring give me the willies just to look at. First, there is the matter of it being on the front end. Unless you drive in reverse all the time, a front wheel is the first to arrive at any pothole you hit. By the time the rear wheel arrives at the pothole, the front wheel has already taken the brunt of the impact and speed is reduced, so the rear suspension has less to absorb than the front does. Also, unless you're in an old VW, the weight of the engine is sitting on the front wheels. If a transverse monoleaf spring fails, YOU WILL SUDDENLY HAVE NO STEERING CONTROL! The car is going to dart very sharply toward the side that breaks, due to the axle being pushed back and the weight of the car shifting toward that side. I've dis***embled many old Ford transverse springs, and I've found my share of broken spring leaves, but I've never seen a main leaf fail--for exactly the reason that F1 Flathead explained. With the stock spring, you are more likely to crack the center of the crossmember (seen that many times) than you are to break a main leaf. If you're going to run a monoleaf, be sure that there is no binding in your spring shackles and have really good shocks.
No ,I'm not gonna get mad , but I am a little confused about what your disagreement is . Just to clarify ( not argue ), All I meant was this.... A monoleaf spring has one leaf and a handful of spacers .One job of the spacers is to take up space in the crossmember to equal the thickness of a multi-leaf spring so the u-bolts will tighten up . Then if the car sits too high or low, you can move those spacers around , all on top of the leaf ,all below the leaf , or any combination . That changes ride height because it moves the leaf up or down in the crossmember . With a multi-leaf spring , you cant just arrange the leaves any old way you want . I think we're on the same page , but you lost me with all the ****** talk .
Ha ha, that's cool. i don't REALLY mean are ya mad, I mean like in a friendly poke at ya way. I'm following with you on the spacers, I just didn't think that any of it had anything to do with spring rate. That's what my first post was about, spring rate being independent of what kind of spring or how it's mounted. I know the shims don't change the spring rate, I just took it one further and took the position that you could change the ride height on a multileaf and also not change the spring rate... After that, I was giving you a bit of a hard time for sport. (spring rate...Pamela Anderson...there's a fertile joke lurking in there)
Ive broken 2 mono springs on my cars over the years, so I no longer use them. I have switched to using Posie Super Slide Springs and have no problems with ride or breakage. Both cars had SBC engines in them so weight was not a factor. They both broke in the middle of the spring.
I know of 3 mono's that have broken here in england, personally i don't like them, I've never had a Posies spring break.
We are agreed then . This is all making me think I'll just keep my mono-leaf that's in my tub as a set up spring in the shop and replace it with a normal spring before I finish it . All these stories are freakin me out .Lots of theories on why they break , but I don't want to be a statistic .
A bunch of guy have seen it, but only one posted a picture. Sounds like a very limited problem. I'll stick with multi leafs for my own peace of mind though.
Would like to see a close-up well-focused of BOTH of the broken ends. That little rust spot with a halo around it is very interesting.
I think the post on here or the other thread about this that talked about a flat or arched perch could be the key. The perch does need to be slightly curved or the center of the spring is catching extra hell all the time. I am going to run a mono-leaf on a project soon. Just going to inspect the spring very carefully for imperfections before installing it. Maybe smooth it up some first too if need be. This thread has got me thinking about their safety though.
You don't really want to do any "smoothing up" of a leaf spring (or any spring). The surface of good springs is shot peened to induce a residual compressive stress to the surface. As you bend a spring, one surface is compressed and the other is stretched. The residual compression left from shot peening keeps the outer surface of the spring from going into tension as the spring is bent. Because it is not in tension, small cracks and surface imperfections don't tend to open up and propogate into big cracks. If you remove metal from the surface, you remove this compressed layer. Dan
A word here on chrome springs and hydrogen embrittlement. Any type of electro- plating can cause hydrogen emb. from what I was told by an engineer familiar with this subject.There standard was to bake within 3 hours after plating. If you wait too long it is too late. I think it was 350deg for 2 hours. Ago <input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden">
Yes, any acid processing on heat treated steel has potential to cause hydrogen embrittlement (HE). Any plating is a very common source: chrome, nickel, zinc. Baking after removal from the tank is the corrective action to minimize the HE potential. General rule is 400F for 4 hours within 4 hours of tank removal. Can be 350F and less time, but higher temp and longer time is better. HE does not cause the spring to break by fatigue. HE is a totally different mechanism and if truly HE will cause failure in 72 hours. HE is an intergranular cracking (along grain boudaries) and requires a sustained high tensile force. Not a cyclic tensile force like fatigue cracking which is intragranular cracking (through the grains).
Ok guys, go to my follow up post "Monoleaf broke follow up" and get up to date photos and comments. _______________________________________________________________________ Still think OKC ****s big time.
I agree. I have a '71 Vette & one of the leafs broke, but it all stayed together because of the clamps, & it was in btwn other leafs. It also damaged the u-joint on that side because of the extreme neg camber after the break. Could have been dangerous tho if it didn't stay together.
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