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Parabolic spring snapped.


Betsy
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I have just had a nightmare weekend. I was greenlaning with friends in the Peaks, when on a particularly rocky lane, my right rear parabolic snapped 2 out of 3 leaves, and the 3rd leaf was left looking very fragile. We manged to eventually recover the vehicle to a road ready for breakdown services, but we would have needed a large block of wood and a couple of ratchet straps to secure the rear axle had the 3rd leaf snapped.

This is the second time this has happened - last time was a front spring when both leaves snapped.

My vehicle is a 109 soft top 2a. She has a mechanical front winch, the weight of which was blamed for the earlier front spring failure. CP replaced the fronts for HD items FOC, and these have been fine ever since but give a hard ride.

The rears were standard 3 leaf para's. I have done about 15000 miles on them including a trip to Morocco with a moderate load. I also do regularly go off road and the lanes around here are notoriously rocky. One thing the parabolics do give is amazing articulation, thus improving the off road ability of the series vehicle. This has raised my concern for the durability of parabolic springs on a vehicle used off-road.

I don't think I have been overloading the rears, they certainly seemed to be sitting at normal height with all the kit on board. Lately, I have been noticing it was very difficult to set of from a standing start without a certain amount of kangaroo stylee lurches. This was probably due to the spring winding up.

Anyway, I have decided to remove the parabolics and replace them with a new set of standard 109 springs. This may compromise the off-road ability of the vehicle, but at least they should last longer than parabolics.

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Happened twice to me as well, once at the fronts and than at the rear. I have gone to standard springs in front, but still run paras at the rear. Mine where an early set from ti console. They replaced them for me but i said never again in front, not worth the money.

Pic for the record

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... Lately, I have been noticing it was very difficult to set of from a standing start without a certain amount of kangaroo stylee lurches. This was probably due to the spring winding up.

Due to the spring winding up, yes I tend to agree, but probably winding up because one of the leaves had cracked already. This weekend it cracked the second.

Shame you had the problem, with your Morroco trip etc I'd always thought your experiences were a valuble lesson to us all. Perhaps they still are, but not in the way you hoped :-)

Are you aware there seems to be another player in the market? Only supplies Trade, but currently that's through Paddocks, who appear to have dropped their earlier supplier. Unfortunately I can't recall the UK web site of the spring maker.

Good Luck.

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Spring wrap could easily explain that sort of failure.

It's one of those things you never notice till you start looking, I've noticed Series running paras do wrap very easily off-road.

On and off. I'm sure that you must get some wrap if you set off on road with a little errr... vigour. Do I recall that you set up a pretty useful anti-wrap system on your axles, or was I imagining things?

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On and off. I'm sure that you must get some wrap if you set off on road with a little errr... vigour. Do I recall that you set up a pretty useful anti-wrap system on your axles, or was I imagining things?

I did, and it made a massive difference - obviously the extra leverage of the portals and big tyres exaggerates wrap but the anti-wrap stopped all that dead. When watching other Series at play days etc. I find myself watching the springs, especially on climbs, and you can watch the front paras wrapping as the front end scrabbles for grip and bounces about.

Original anti-wrap bar post here should anyone be interested.

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Thanks for all the replies chaps :i-m_so_happy:

I'm a little disappointed, because they did perform so well in Morocco, and have been pretty good all round. Its no doubt that for a road use only Series Land Rover, para's would be the only thing to have. If you want to use it off road, and especially if you want to explore the greater axle articulation, it looks like you should expect an eventual failure unless you modify the vehicle with anti wrap.

I personally do not want to modify the vehicle any more than it is, so will be fitting a set of standard springs. They will be poly bushed.

Whats the view on retaining the ES3000 Pro Comps that I have fitted? will they be too soft for standard springs?

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Why not try the heystee, send an email to Paul and tell her your story.

I think he has the right paras to your Land.

Systems available for Land Rover Series II, IIA & III

88" (SWB), Load level A, suited for lightweight but serious off-road driving HST 715.10.1 e-mail

88" (SWB) & 109 (LWB), Load level B, suited for serious off-road without compromising load capacity HST 715.10.2 e-mail

109" (LWB), Load level C, suited for stationwagons in all-round conditions HST 715.10.3 e-mail

109" (LWB), Load level D, suited for heavy duty overland trips with maximum load and serious off-road HST 715.10.4

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  • 3 months later...

Why not try the heystee, send an email to Paul and tell her your story.

I think he has the right paras to your Land.

I've just discovered this thread.. I fitted Rockymountain parabolics , 4 leaf rears, 2 leaf fronts to my 109" SW before I drove Overland to Kazan in Russia.. After covering 20,000 miles over all types of terrain I then attempted a drive to Tanzania.. I got as far as Syria before having to abandon the trip due to wars and closed boarders.. However a few years later and after a vehicle rebuild, the Rocky Mountain springs are still as fresh as they were when new, the arch remains and no problems experienced with them.. Ive been through a few sets of shocks tho..

Rocky Mountain Springs feature a number aspecs in their design.. Like the HeyStee springs the 4 leaf rears have proper 4 leaves in the spring pack and not additional helper leaves.. The springs are surface peened to prevent cracking, a feature not mentsioned by the other parabolic spring makers.. These springs have been used over many hard miles of harsh terrain, not tarmac roads and are well flexed regularly off road.. So when choosing springs you should check for features such as surface peening to prevent cracking, avoid springs with added helper leaves.

Heystee do appear to be a premium spring maker and the cost reflects this..

The Rockymountain springs do not appear to have the same premium image, and have a more humble paint job on arrival, but the quality of the spring steel, the spring surface treatment and the fact that they have covered distance and hard terrain reliably for me, without showing signs of degrading, would make me strongly recommend RockMountain springs to anyone else.

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Front axle wrap on series vehicles is bad enough without making things worse by fitting Parabolics.Parabolic technology has been around for decades, but Rover persisted with multi leaf designs except for the 101 models. Just have a look at the extra work and material involved in manufacturing multi leaf springs. This costs more money but if done correctly produces a stronger more flexible and higher durability product.I think It's to do with surface tension.For the sake of explaination . Bend a 1/4'' thick length of timber for example and the surface doesn't stretch very much, it flexes and returns to shape. Take a 2'' thick piece of timber of the same length and bend it the same amount and it is much less flexible and may break because the surface has to stretch much more.

Bill.

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Front axle wrap on series vehicles is bad enough without making things worse by fitting Parabolics.Parabolic technology has been around for decades, but Rover persisted with multi leaf designs except for the 101 models. Just have a look at the extra work and material involved in manufacturing multi leaf springs. This costs more money but if done correctly produces a stronger more flexible and higher durability product.I think It's to do with surface tension.For the sake of explaination . Bend a 1/4'' thick length of timber for example and the surface doesn't stretch very much, it flexes and returns to shape. Take a 2'' thick piece of timber of the same length and bend it the same amount and it is much less flexible and may break because the surface has to stretch much more.

Bill.

If you look at the WW2 Willys MB jeep it was fitted with anti-tramp bars as standard.

I have 9.00 tyres and when they spin, they did use to cause noticable axel tramp with my the original Multi leaf springs., But this effect has been reduced with the parabolics..

I have found many cracked leaves during the time I had multi leaf springs..

The original multi leaf springs are easier to manufacture, compared with parabolic springs.. Parabolic springs vary in crosssection so in theory should be less prone to cracking from concentrated loading.. If they are made correctly, surface peening prevents lines of stress forming and will help to reduce the risk of cracking, correct tempering will allow the spring to retain their arch and resist bending..

From the S shaped spring picture to the Cracked leaf shown, this suggests that some vital flaws in the heat treatment and variables in the steel used has to be concidered.

Remember theres a fine line in heat treatment between tempering and hardening.. If the steels alter slightly in their material and composition it would be very easy to over harden when tempering or not evenly temper the material at all.. This why we see examples of a cracked springs, they've been overharded, and a banana shaped spring which is soft and is below the state of being tempered, It hasnt been treated enough. Those springs should be covered as a fault in manufacture otherwise it becomes very expensive.

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If you look at the WW2 Willys MB jeep it was fitted with anti-tramp bars as standard.

I have 9.00 tyres and when they spin, they did use to cause noticable axel tramp with my the original Multi leaf springs., But this effect has been reduced with the parabolics..

I have found many cracked leaves during the time I had multi leaf springs..

The original multi leaf springs are easier to manufacture, compared with parabolic springs.. Parabolic springs vary in crosssection so in theory should be less prone to cracking from concentrated loading.. If they are made correctly, surface peening prevents lines of stress forming and will help to reduce the risk of cracking, correct tempering will allow the spring to retain their arch and resist bending..

From the S shaped spring picture to the Cracked leaf shown, this suggests that some vital flaws in the heat treatment and variables in the steel used has to be concidered.

Remember theres a fine line in heat treatment between tempering and hardening.. If the steels alter slightly in their material and composition it would be very easy to over harden when tempering or not evenly temper the material at all.. This why we see examples of a cracked springs, they've been overharded, and a banana shaped spring which is soft and is below the state of being tempered, It hasnt been treated enough. Those springs should be covered as a fault in manufacture otherwise it becomes very expensive.

Tony is absolutely right, and this is why there is such a difference in prices between different manufacturers. TIC/Heystee are horrifically expensive compared to some of the cheap brands, but you get what you pay for. RM are more affordable than TIC, but still dear compared to most others. Correspondingly, their quality is very respectable, but not quite the best available. Cheaper brands then these two are not worth the money - the springs will need replacing far too soon.

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The ''S'' shape in the spring is a product of torque reaction, axle wrap, call it what you like.People have varying opinions about what 4 wheel driving is about. I have fitted Parabolics to three different Landrovers in the past for clients that mainly used their vehicles on mountainous fire trails and during obstacle testing on all 3 cases the increase in front axle tramp was obvious.

Some older members of this forum will know that I have always been critical of the standard LandRover front suspension design re axle location,which I believe is due to having shackles on the wrong end of the spring. IMO and personal experience of running parabolics on the rear of my own vehicle, they are not the answer to perform the dual duty of suspending and adequately locating the axle assembly. Before I made the ''A'' frame to locate my rear axle I was regularly breaking or kinking the Transit parabolics that I use. They don't do that anymore. As for the job of purely suspending the vehicle on rough corrugated roads over many thousands of miles, multi leaf springs win hands down. The successful aftermarket spring manufacturers that supply suspensions for outback Australian conditions produce multi leaf springs not parabolics for good reason.

Bill.

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The ''S'' shape in the spring is a product of torque reaction, axle wrap, call it what you like.People have varying opinions about what 4 wheel driving is about. I have fitted Parabolics to three different Landrovers in the past for clients that mainly used their vehicles on mountainous fire trails and during obstacle testing on all 3 cases the increase in front axle tramp was obvious.

Some older members of this forum will know that I have always been critical of the standard LandRover front suspension design re axle location,which I believe is due to having shackles on the wrong end of the spring. IMO and personal experience of running parabolics on the rear of my own vehicle, they are not the answer to perform the dual duty of suspending and adequately locating the axle assembly. Before I made the ''A'' frame to locate my rear axle I was regularly breaking or kinking the Transit parabolics that I use. They don't do that anymore. As for the job of purely suspending the vehicle on rough corrugated roads over many thousands of miles, multi leaf springs win hands down. The successful aftermarket spring manufacturers that supply suspensions for outback Australian conditions produce multi leaf springs not parabolics for good reason.

Bill.

I can see the S shape is a result of 'spring wrap' but I question the quality of the spring.. For a correctly tempered spring to bend like that I would expect it to crack long before.. Then again, if you go past a springs elastic limit it will then become malleable so if you are using low rate springs for soft ride and maximum travel they will eventually flatten or bend into an S shape instead of resisting Axel wrap.

The standard land rover Leaf spring front/rear suspension design is a very simple conventional design and works very well at locating the axels in place.. Unlike designs with front mounted shackles the rear mounted shackles are done to give better steering reaction on the road. With front mounted shackles, as the vehicle leans while cornering at speed this causes the leaning side of the axel to move forward, effectively increasing the turn-in on the front wheels.. The opposite effect happens with the rear mounted shackles, as the leaning side of the axel to moves back slightly, reducing the effective steering angle, so working as a kind of fail safe for high speed road use..

One on the best, simplest designs for axel location is Fords transverse leaf spring method.. An A frames locates the axel and a transvers semi eliptic spring provides the absorbsion

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Bill is right about multi-leafs, however I have beaten the absolute bejaysus out of my TIC parabolics (the last 3 years they've done several thousand miles fully laden at speed on Russian roads supporting portals & 37's) and they are still the right shape.

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