During my 2003 car's service and MOT at 53,000 miles, it was discovered by my Ford dealer that the lower end coil of both rear springs was fractured. I avoid potholes like the plague, and drive at less than 10 mph over the one and only speed hump I encounter, so the failures can't be blamed on either of those factors.
I don't know when the failures occurred because they produced no symptoms. I've asked the dealer to return the original springs to me so that I can inspect them. They tried to show them to me with the car raised on a hoist but the fractures were obscured too much by the lower spring cups. I assume that the failures were initiated by corrosion.
The fact that they'll need my car for a second day ~ they didn't have new springs in stock ~ won't be a problem because they've extended the loan of the 2007 1.8 litre petrol Focus Sport courtesy car until my car is finished.
Last edited by: L'escargot on Tue 22 Jun 10 at 17:47
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im replacing a spring a week now
in fact this week ive done a clio rear
and a punto front
i blame potholes not speed bumps
and the stresses of power steering on inferior spring material
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Isn't it down to the fact that modern coil springs manufactured in Europe are prone to failure because of the way they are made - the ends of the springs not being finished off properly allowing corrosion to take place. I think European manufacturers tend to flatten the ends of springs, rather than using a process called pigging.
Last edited by: Auristocrat on Tue 22 Jun 10 at 20:29
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>> I assume that the (spring) failures were initiated by corrosion.
Could be poor or faulty material, poor finish (corrosion, damage), poor damping (excessive load), design problem. Erm. Anything else?
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More likely to have been caused by materials defect, specification issues or manufacture.
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Or the accountants saving 10p per car made on the spring material - whilst providing a good source of income to both themselves in replacment springs and the garages for fittig them!
Vive La oleopneumatic suspension sphere!
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This was unheard of a few years ago, and is now affecting all makes and models.
To my mind, it has to be a combination of:
Woeful road surfaces
Speed humps
Heavier and heavier cars
Penny pinching by manufacturers.
My VW tech friend reckons their workshop does 4-5 spring replacements a DAY!
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>>Could be poor or faulty material, poor finish (corrosion, damage), poor damping (excessive load), design problem.
Armed with the knowledge that springs are failing at both ends of a large number of different makes and types of cars, taking these ideas in turn;
>>faulty material
A large number of makers - Ford, Vauxhall, the French ones, BMW and others ALL having springs made from faulty material? No, that's not credible
>>poor finish (corrosion, damage),
I think this is explains most of what we see - more below.
>>poor damping (excessive load)
By the time that poor damping would appreciably affect spring loads, the car would have failed the MOT - and, this can't be the case for all the manufacturers who have spring peoblems.
>>design problem.
I can't beleive that a large group of manufacturers who used to be able to design coil springs to last the life of the car have suddenly forgotten how to do it - en masse!
In my work, I know it's now difficult to specify heavy metal coatings - hexavalent chrome, or more relevant for springs, Cadmium. Fortunately, I work in an area where we have some happy exemptions, but, I can't imagine road springs qualifying.
The fractures I have seen do have corrosion evident in the area where the crack initiated - it's a very small thumbnail area about 1 - 2 in diameter. You need to view the fracture quickly after the spring breaks - general corrosion products begin to form over the fresh area of the break during the first 24 hours - leave it a day or two, and without some chemical and mechanical prep, you will not be able to identify the initiation point any more.
So, I blame the EU!, and general misplaced application of "green" laws (see W124 wiring harness problems for another example!)
As you can imagine, I think the line taken by a well known motoring site is not correct, and blaming potholes and speed bumps is nonsense.
Last edited by: Number_Cruncher on Tue 22 Jun 10 at 21:55
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>>faulty material
>>A large number of makers - Ford, Vauxhall, the French ones, BMW and others ALL >>having springs made from faulty material? No, that's not credible
>>I can't beleive that a large group of manufacturers who used to be able to design coil >>springs to last the life of the car have suddenly forgotten how to do it - en masse!
Its feasible that most european makers get them from a single source, and its more feasible that the price has been forced so low that known standards and or durability have been sacrificed.
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One of my rear springs had snapped allowing the car to lean to one side. It's a common weak point on E36 BMW's. My mechanic showed me the broken spring and it does seem that the fracture was initiated by corrosion.
So why did we not have this number of spring breakages in the past? Is it because the suspension was softer, so less load on the springs, or were the springs just better made?
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Is it because cars ( and some people ) are getting heavier ? Neighbour of mine has a fat wife and she fills the passenger side of his Focus. Can't see how he would have got one that size in an Anglia a couple of generations back.
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>> Is
>> it because the suspension was softer, so less load on the springs,
Spring load is largely a function of the weight of the car, not the spring rate.
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>>Spring load is largely a function of the weight of the car, not the spring rate.
You're right, I havn't thought it through :-)
A few years ago, a guy at work had the front spring snap on his Rover SD1. The strut dug into the side of his tyre and demolished it. I asked him if I could have a look at the tyre in his boot, and being stupid, picked it up to get a closer look. Thats when I found out about reinforcing wires that run through the tyre, because the sheared ends found their way into my skin, and left a dozen blood spots in the fingers. I learnt my lesson the hard (and painful) way...
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>>Its feasible that most european makers get them from a single source
Barely feasible - it isn't as though springs are a high tech item, and I would be surprised if even for a single model of car the springs don't come from multiple competing suppliers.
>>and its more feasible that the price has been forced so low that known standards and or durability have been sacrificed.
I could believe that if it were just one maker, or one model at a time, but, I can't see how that would magically happen across many makes and models - all at different points in their design life cycle - all at the same time.
If you look at some failures, they are usually in the area of the spring where the plastic coating has failed and there is corrosion beneath (whether the corrosion causes the plastic to fail, or vica versa isn't obvious). If the problem were of a more general poor specification, or poor material quality, the defects from where the crack initiates would be more evenly distributed along the length of the spring.
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think of the poor guy replacing these springs
me for instance
i really do get the heeby geebies compressing new springs as i get the opinion one at any time can break and a splinter of steel could pierce my body
i really dread doing road springs
its dangerous work
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Hasn't this thread been done to death previously?
My ole '93 Kia Pride's still on its original springs, AFAIK, and what about the Jowett on this forum?
Anybody want to do a subjective analysis by comparison?
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>> Hasn't this thread been done to death previously?
No it hasn't. What's been done to death is people claiming that their car's springs were broken by them having to drive over potholes and/or speed humps. I'm saying that mine weren't.
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>> i really dread doing road springs
>> its dangerous work
I do most of my own repairs and servicing but when a spring broke last year I took the car to a garage for the same reason BB.
Also I had a 15 year old Renault 19 with full history, dealer then independent garage then a load of motor factor receipts. That still had it's original shocks all round and original front springs, although the torsion bar had some work done at 12 years iirc.
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Well, I took the old springs home with me and inspected them.
Both were in a similar condition. The plastic coating had become detached from the lower two coils where the spring sat in the supporting cup. The plastic coating on the rest of the spring was still intact. The lower two coils were heavily corroded and the failure had occurred about one and a third coils from the end. The faces of the failure were heavily corroded and my guess is that it had been like that for some considerable time ~ probably years rather than months. I'm satisfied that the failure was initiated by the corrosion and had nothing to do with driving over potholes or speed humps. The car exhibited no symptom of the failure when being driven. I think the only reason it was spotted on this occasion was that the spring became more exposed when the suspension was lowered to allow new rear brake discs and pads to be fitted. I was offered pattern parts but I specified that all parts renewed should be genuine Ford.
In future I will probably view road springs as being consumable items in much the same way as brake discs.
I can't help but wonder how many people inspect the old spring(s) before making their diagnosis of the likely cause of failue.
Last edited by: L'escargot on Thu 24 Jun 10 at 07:23
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The practical advice I would offer to those concerned about road spring failure is to coat them with something to help to protect against corrosion - waxoyl perhaps?
>>I can't help but wonder how many people inspect the old spring(s) before making their diagnosis of the likely cause of failue.
Yes, I agree fully - few is the conclusion I have reached - hence the prevalence of bogus explanations pointing to potholes or speed bumps, pigtailing of spring ends and other nonsense.
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"The practical advice I would offer to those concerned about road spring failure is to coat them with something to help to protect against corrosion - waxoyl perhaps"
I use waxoyl) on everything rusty underneath the car - once a year..
(except exhausts and disks..)
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> I was offered pattern parts but I specified that all parts renewed should be genuine Ford.
Given that the parts that failed were genuine Ford, one wonders why you specified them again.
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>> Given that the parts that failed were genuine Ford, one wonders why you specified them
>> again.
>>
>>
Better the devil you know than the devil you don't.
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>> Better the devil you know than the devil you don't.
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Yes at least the ford springs snapped in such a way that they didn't cause any other damage, like shredding a tyre.
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does not mean they will do so next time, or that pattern springs wouldnt. What you do know is that Ford springs break.
Last edited by: Zero on Thu 24 Jun 10 at 09:59
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Yes at least the ford springs snapped in such a way that they didn't cause any other damage, like shredding a tyre.
>>>>>>
>>>>>>>thats because they have a full cup rather than a miniscule one so the spring cant slip down the strut and pierce a tyre
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>> or that pattern springs wouldnt.
Because pattern part manufacturers don't have access to the original drawings, they can only guess at dimensions, tolerances, material specification, heat treatment, surface coating or trearment etc etc etc.
No thanks.
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It's a suspension spring, not a rocket motor.
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They look like rocket motors to me!
:-D
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>> It's a suspension spring.....
>>
Exactly, and as such has had a lot of R & D, you get the best compromise of ride/handling, for each individual engine/trim combination, in many cases there may be upwards of 4 different springs listed by the vehicle manufacturer, in the patten part catalogue you will be lucky to see more than one!
that WILL effect the ride/handling of the vehicle to a greater or lesser extent.
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>> Because pattern part manufacturers don't have access to the original drawings, they can only guess
>> at dimensions, tolerances, material specification, heat treatment, surface coating or trearment etc etc etc.
>>
>> No thanks.
>>
Or hire a car for a day or two, take the part off, take some measurements and put it back on.
How do you think car manufacturers come up with solutions similar to their competitors ?
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>> How do you think car manufacturers come up with solutions similar to their competitors ?
>>
A tale.
About 3 years ago a new model top seller small car was launched, i was instructed to go and collect one of these from a tiny dealership in the back of beyond...no destination, only a purchasers name, after i'd collected said vehicle i was routed via a regular export dock run and topped up the truck with other vehicles.
After i'd discharged the top up vehicles only then was i told to deliver this vehicle to another quay of the same dock, the shipping notes miraculously already there..
It was being shipped thousands of miles to a competitors headquarters.
I suppose they all operate similar cloak and dagger routines to get their hands on new normal production models.
Things like spring dimensions would be easy in comparison.
Last edited by: gordonbennet on Thu 24 Jun 10 at 21:20
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I remember touring a Ford R&D establishment in Dunton many years ago and seeing non-Ford cars totally stripped, I was told that they regularly procure competitor cars and take them apart to see how they worked...
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>> >> Because pattern part manufacturers don't have access to the original drawings, they can only
>> guess
>> >> at dimensions, tolerances, material specification, heat treatment, surface coating or trearment etc etc etc.
>> >>
>> >> No thanks.
>> >>
>> Or hire a car for a day or two, take the part off, take some
>> measurements and put it back on.
That would only give them the dimensions of those particular samples. It would not tell them the original drawing dimensions and tolerances.
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>> That would only give them the dimensions of those particular samples. It would not tell
>> them the original drawing dimensions and tolerances.
close enough, Its a suspenson spring, the dimensional tolerances are not sub milimetre critical. Its very very very easy to reproduce an Item like a spring and meet all the orginal specifications.
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I agree. Besides, apart from the major body pressings, panels, and the engine and gearbox, very little of a car is actually made by the manufacturer. It's all bought in from third parties and then assembled.
The "utopia" is to find out who makes a part and go direct, although in the case of a suspension spring, the cost saving would be minimal. I know a friend took this route with a headlight for his Elise, and paid about half what a Lotus dealer wanted. It came in a Valeo box rather than a Lotus one, otherwise absolutely identical. French manufacturers are useful for this, as they tend to stamp the manufacturer on things like filters, brake pads and discs alongside their own logo. The likes of GSF can save you 50%+ on identical parts.
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>> ....... the dimensional tolerances are not sub milimetre critical.
The spring wire will have a diameter tolerance in the region of +/- 0.025 mm, and an ovality tolerance in the region of 0.014 mm maximum.
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most road springs have colour identification marks on them so its easy to confirm you have purchased the right spring for your particular model
secondly if you buy from a proper factor you normally find they have weeded out poor component makers as they like us dont like parts failing as it causes hassles somewhere down the line
anyway as already said most components are made by independant manufacturers and they also make stuff for the aftermarket,the problem comes when countries like china copy products and get agents top sell them via internet sites this is where problems can arise on safety critical items
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>> >> ....... the dimensional tolerances are not sub milimetre critical.
>>
>> The spring wire will have a diameter tolerance in the region of +/- 0.025 mm,
>> and an ovality tolerance in the region of 0.014 mm maximum.
So, you know the "tolerances" - you, too, could become a pattern spring maker, making perfectly good or superior springs, like all the others.
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>> >> ....... the dimensional tolerances are not sub milimetre critical.
>>
>> The spring wire will have a diameter tolerance in the region of +/- 0.025 mm,
>> and an ovality tolerance in the region of 0.014 mm maximum.
well within the ability fo someone to copy. Piece of cake.
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>> Its a suspenson spring, the dimensional tolerances are not sub milimetre critical. Its
>> very very very easy to reproduce an Item like a spring and meet all the
>> orginal specifications.
Quite so. Some firms also produce springs rated better than the originals.
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I took both broken springs to a former colleague who is a metallurgist and who now works for a spring research organisation, and where he gave the springs the full monty. He said the material specification and quality and the standard of manufacture were all first rate. His conclusion was that the most likely cause of the failures was the gradual propagation of cracks initiated by the corrosion at the lower end of the springs, and was not associated with driving over potholes or speed humps.
He said it should be borne in mind that at the design and development stage, and during regular quality audit testing of production springs, both the spring manufacturer and the customer (i.e. the car manufacturer) would subject batches of springs to durability tests comprising over a million cycles of compression and relaxation on each component. Compared to these tests, the effect on springs of driving over potholes or speed humps would be insignificant.
He added that on several occasions in the recent past he had been commissioned to inspect broken springs removed from cars whose owners had claimed compensation from councils for damage the owners had said was caused by driving over potholes or speed humps. In all cases his report to the council concluded that the owner’s claim could not be substantiated and should therefore be rejected.
I doubt very much whether many car owners take the trouble to even give their broken spring(s) as much as a cursory glance before trying to jump on the “potholes and speed humps damage” bandwagon.
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>> I took both broken springs to a former colleague who is a metallurgist and who
>> now works for a spring research organisation,
Thanks for the follow up L'escargot, makes interesting reading.
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>> He said the material specification and quality and the standard of manufacture were all
>> first rate. His conclusion was that the most likely cause of the failures was the
>> gradual propagation of cracks initiated by the corrosion at the lower end of the springs,
Thanks for the feedback.
However if quality and standard of manufacture were first rate, why did the anti-corrosion coating break down? Or is 7 years considered to be an adequate service life?
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I'm just pleased that the spring failures didn't cause any other damage or produce any adverse symptoms when the car was being driven. In future I'll probably treat springs as being consumable items. It's not as if it cost a small fortune to have them replaced.
Last edited by: L'escargot on Mon 12 Jul 10 at 09:12
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>However if quality and standard of manufacture were first rate, why did the anti-corrosion coating break down? Or is 7 years considered to be an adequate service life? <
Yes indeed, what counts as 'first rate' these days?
In the world of the second rate, Ford road springs (and others) last seven years - if you're lucky.
Poor quality materials, inadequate manufacturing technique (ie, plastic coating that peels off) and road salt seems the simple answer.
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I think I read somewhere that the heavy metals that were used in treating the springs for corrosion protection had been banned.
EDIT:- Yes it was N_C way back up the thread!
Last edited by: Old Navy on Mon 12 Jul 10 at 11:13
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>> >However if quality and standard of manufacture were first rate, why did the anti-corrosion coating
>> break down? Or is 7 years considered to be an adequate service life? <
>>
>> Yes indeed, what counts as 'first rate' these days?
>> In the world of the second rate, Ford road springs (and others) last seven years
>> - if you're lucky.
>>
>> Poor quality materials, inadequate manufacturing technique (ie, plastic coating that peels off) and road salt
>> seems the simple answer.
>>
Thanks to L'escargot, this thread has been brought some real new information. Not the BS, spurious rumour, and conjecture about pig-tailled spring ends and potholes that you might find published elsewhere as if it were fact.
>> seems the simple answer.
The answer won't be simple.
The metal that the spring is formed from will be first rate - and I imagine this is what the metallurgist meant. It must be first rate, as sny significant defects in the spring material itself would have meant rapid failure much shorter than the 7 years being discussed. As the springs are so both highly stressed, and see a large stress range in use, even a small defect will cause a crack to propagate rapidly.
That the plastic coating comes off, and corrosion is found beneath there is important to this failure, but, I've never seen any springs which have anything better on them. As I've mentioned before, I suspect that the heavy metal plating of spring materials is now curtailled by EU legislation, and as far as I am aware, there aren't good replacement techniques available. It isn't a question of only the cheaper manufacturers being affected, or somehow corners in specification being cut.
The question I would like to look into now is which comes first, the peeling of the plastic, or the corrosion of the surface of the spring? If the former, then, there's something that a DIY owner can do. If the plastic peels, waxoyl or similar applied to the spring may prevent corrosion assisting crack growth.
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So over what sort of timescale would the crack propagate NC? Minutes.... days??
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Just to add my tuppence-worth:
I think it's got to be corrosion over time, rather than bumpy terrain over mileage, that does for springs. I've driven several cars 100, 200, even 300,000 miles in very short timescales without ever breaking a coil spring. They were all minicabs therefore they were subject to all manner of potholes, kerbs and speed bumps/tables/cushions, usually in a hurry.
Then last winter I had a spring snap in my 13-year-old 100k Escort and my dad snapped one in his 5-year-old 70k C-class.
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>> So over what sort of timescale would the crack propagate NC? Minutes.... days??
>>
The quick answer is that there's no quick answer to that question!
The rate of crack growth varies quite significantly over the lifetime of any crack. When the crack is small relative to the critical size, it can propagate very slowly indeed. As the crack nears the critical size, it speeds up, both in terms of growth per unit time, and in terms of growth per stress cycle. The final fracture, once the crack has become critical, takes place at a reasonable proportion of the speed of sound in the material [shear waves propagate at about 3km per second in steel]
In the case of springs failing, I would expect to find other small cracks near the fracture site, but, the one that caused the fracture, effectivley "won" the race.
It is these many tiny cracks which cause springs to sag with age - the growth of each crack allow a small volume of metal to relax.
So, while at the tiny end of the spectrum you can have cracks in springs which remain there for years, and I would be surprised if any crack that had grown to failure was less than a year old, spending most of its life very small.
In large engineering structures, dealing with exisitng cracks and predicting their future growth rates is a vital part of asset management [large structures typically have unavoidable defects in them right from being brand new - especially where there are welded joints]. I've been involved in this predicitve fracture mechanics work for rail vehicle owners, which defined overhaul intervals, and operators of nuclear plant, while my colleagues have also worked on crack propagation studies on civil engineering structures and offshore equipment.
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>> Yes indeed, what counts as 'first rate' these days?
Please don't quibble about the words I used. I didn't get a writen report so I probably didn't quote my advisor verbatim.
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Ford Focus - It's not been caused by potholes or speed humps. - Bellboy
