George Macdonald wrote:
> On Mon, 18 Apr 2005 05:56:59 -0700, jim beam <nospam@example.net> wrote:
>
>
>>George Macdonald wrote:
>>
>>>On Sun, 17 Apr 2005 07:45:58 -0400, Imminent Vengeance <me@privacy.net>
>>>wrote:
>>>
>>>
>>>
>>>>George Macdonald wrote:
>>>>
>>>>
>>>>
>>>>>Depends where you live but that suspension system is prone to broken front
>>>>>springs in the frost belt - the spring breaks just where it enters the
>>>>>perch on the shock. Because of where the break is, you probably won't even
>>>>>notice any difference in ride/handling but you might hear a "doink" when
>>>>>you get out of the car on the side with the break; you'd definitely hear
>>>>>the "doink... doink" when you jack the front up. The break *can* put some
>>>>>side force on the shock which will wear it out quicker.
>>>>>
>>>>
>>>>The only time I broke a spring on my '93 Accord, it was at the other end of
>>>>the coil, at the top where it enters the strut mount. But I think this was
>>>>the result of that corner of the car jumping a huge curb while swerving to
>>>>avoid a bad driver.
>>>
>>>
>>>The break often happens on a violent bump but the root cause is usually
>>>weakening of the metal due to corrosion where water/salt gets through a
>>>hole in the epoxy coating of the spring. The upper spring seat has a
>>>rubber doughnut in it so there's no wear of the epoxy there. I've heard of
>>>the upper end going but AFAIK the lower is more common because of epoxy
>>>wearing away where it contacts the metal of the perch. If you live in a
>>>"corrosion area" it's worth checking springs for nicks in the epoxy...
>>>which *can* be caused by some of the (cruder) tools used to compress the
>>>spring, e.g. when swapping shocks.
>>>
>>
>>i've seen brand new springs with such nicks. bad [neglectful] handling
>>handling at the factory. as you say, corrosion pitting starts & that
>>causes a stress riser that initiates fatigue. it's the fatigue cracking
>>that kills the spring.
>
>
> Funny thing is I've always thought that spring metal can easily be made
> fairly corrosion resistant.

sure, there's all kinds of non-ferrous springs, but they're fiercely
expensive. i know honda springs don't seem "cheap", but believe me,
they are compared to the alternatives. also bear in mind that steel is
relatively high modulus compared to other materials and silicon/carbon
steel typically used in auto springs has a very high yield point
compared to most fatigue resistant stainless steels. lastly, spring
wire has to be comparatively soft for the forming phase, then heat
treatable to become hard and resistant to yielding. stainless steels
exist that have these kinds of hardening reactions, but they're a big
step up in cost.

> If Honda thinks they can skip that because of
> the epoxy coating, somebody there is dreaming. The Lyle tool I used to
> replace my springs really did a number on the brand new spring coating -
> tried to patch with epoxy glue and hoping it'll hold for a bit.
>
just rust resistant paint works fine. trouble is, once you have some
corrosion, you have pitting & therefore potential fatigue crack
initiation. strictly speaking, springs in that condition should be
replaced, but i can't say i'm a strict adherant to that rule. depends
on mileage & condition.

interesting you mention the lisle tool. i was extremely unimpressed
with the principle of that device, for the reasons you're describing
happened. i therefore built my own - does not touch the spring at all!
i'll email a photo to tegger.