CV boot - rapid deteriotion

[petercliffe]

Changed my offside outer drive boot with genuine lotus kit from CN in March 2013 due to slight tear.
Just checked and found the outer edges of the rubber now disintegrating as per photo.
Neither CN (Now Oakmere Lotus) or Lotus themselves are interested as over 12 months old but confirm records show obtained from supplier in 2012
Has anyone else had any issues or ideas why it has done this?

[Ian T]

I have seen this with other rubber parts - I fitted Quintin Hazell anti roll bar end links to my Mk2 Astra a couple of years ago and within a few months the rubbers were badly split and nearing unserviceable, a set of Febi Bilstein replacements and all has stayed well since.

I would guess in your case the parts are old stock and perhaps have dried out, as that was what I suspected of the QH ones on my Astra.

Ian.

[dapinky]

Same here - I fitted new everything to the front suspension last winter, when I came to restart the project in July the bottom balljoint rubbers had split and gone horrible.

Thats with 0 miles. just sitting on the driveway.

I used some old (New/Unused) balljoint covers that I had lying around (and had been for a long time) - they looked fine when i fitted them, but didn't last....

....so I ordered new ones, and no problems .

[Simon_P]

The original outer CV joint gaiter was a high performance rubber design - I think it was used on a Cosworth. Unusual in being rubber rather than plastic.

Inner joints have rubber boots as they have to change length as well as angle. Outer joints have to go through a larger angle only so are more commonly TPE (cheaper). So the design considerations are different

It looks like Lotus have substituted a rubber boot that fits without considering the application engineering. It looks like the installed length is wrong as is the bellows design - Compare it to a picture of the original one!

I would write to Lotus pointing out that the gaiter has failed after a short period of time, when the original part lasts easily for 100k miles or 25 years.
Mention that it is clear that they have substituted a different design for the original part, and ask what design validation they did on the substitute part?

[Jeemy]

Has anybody found a solution to outer CV boots? Mine also has this 'bellows' design - a flute, if that is the right word, at the small end - do I have that right?

We were looking at it the other day and concluded there must be a reason for it but if what Simon says is true and its not even correct, it does imply there were at least a few of these fitted.

I'm just planning on finding something that fits from a modern car, and fitting it; I got the Renault ones for the inners.

Dave mentions here GKN boots, these aren't the ones that failed then Dave? These work?

[dapinky]

Well, they haven't failed yet! - but only time will tell how long they will last for

(they fit inner and/or outer CV)

[Simon_P]

We were looking at it the other day and concluded there must be a reason for it but if what Simon says is true and its not even correct, it does imply there were at least a few of these fitted.

They would only have been fitted as a replacement.

I think that the 'ribs' of the bellows are referred to a convolutes. If the one at the shaft end touches the shaft on both sides it may be for pressure compensation. This would need the groove in the shaft where the clamp goes to be further away from the joint than a gaiter without that feature.

CV joint boots are application specific, so while the diameters may be the same the length, number of convolutes, and the rest of the design may be different. Compare the inner and outer gaiter, and ask yourself why they were designed so different, why the expense if Dave can by one that fits both. Many fit, some might last for a while.

[dapinky]

I think that it is unreasonable to ask any bit of rubber which undergoes stresses in loads of diffferent planes at the same time to last for more than 20 years....

....and whilst I'm sure that the ones I was provided with (being a 'multi-application' type) are not optimal for the elan, I'm equally sure that Lotus didn't put billions of dollars into development of a part specific for the design, and just found something that would do the job....

... material development has obviously occurred over the past 30 odd years, and milages driven (annually) have probably decreased.

As I say, I don't know if it will last as long as the originals, or maybe even longer - what I do know is that they fit (if you want to shorten them by one convolution, then it still fits), they're available, and they're cost effective.

I also know that when I replaced the ball-joint rubbers at the same time (With OE ones), they failed within 4 months of nil mileage!! - so the OE design, made with old materials, or stored badly for many years, is no guarantee of longevity in rubber components

[Simon_P]

I'm equally sure that Lotus didn't put billions of dollars into development of a part specific for the design, and just found something that would do the job....

GKN would have done extensive rig testing on the design, and Lotus spent millions on the vehicle testing. That is why the don't squeak, chafe, perish, melt, leak split (easily) and the originals can last 25 years/ 100k miles and counting. Much, much more engineering goes into the application engineering than you seem to think.

I had ball joint rubbers perish with zero use on another car - that's what you get if you buy stuff from china.

[dapinky]

I had ball joint rubbers perish with zero use on another car - that's what you get if you buy stuff from china.

Mine were Lotus supplied - so maybe they got them from China???? - maybe that's where the 'New' OE CV joint boots come from as well?

I'm well aware of the amount of time and money companies like GKN put into design/testing - but I stand by my statement that the materials in use 30 years ago have moved on a hell of a lot.

Also, I stand by the comment that Lotus would have found something which fitted and did the job.

Anyway - I won't know for a while how long they last (hopefully) - 'coz if I find out within the next 25 years, I'll just replace them again - it isn't hard or lengthy to do

[Simon_P]

Also, I stand by the comment that Lotus would have found something which fitted and did the job.

Lotus wouldn't have found anything. GKN did use a standard GKN inner boot - which is probably still in production and a high performance outer boot which has been unavailable for years. To prove that it does the job you have to do the application engineering ie vehicle specific testing.

Natural rubber hasn't changed much.

[dapinky]

Natural rubber hasn't changed much.

We agree on that ......

.....but it's a shame that the boots aren't made of just Natural Rubber - it's the vulcanising process which has changed, and the chemical additives - otherwise the boots would be yellow and gooey.

[Simon_P]

The material composition of a GKN gaiter will not matter matter - It will have been through all of the environmental and endurance tests. In that respect you can expect it to last 100k miles.

[dapinky]

True - mine had lasted for 128K miles over 23 years

...but I wouldn't use 30 year old rubber technology for my tyres........

...things generally change, evolve and improve (but there are always going to be 'cheap' copies made in the global economy) - and I'm fairly happy that a 'good' modern part is likely to perform as satisfactorily as an 'excellent' part did 30 years ago.

Bearing in mind that some of the processes/chemicals in common use many years ago are now frowned upon, ALL manufacturers have to change their material specifications over time - we can only get what we can get.

Like with brake pads - undoubtably the 'best' material for the job (in common usage terms) is asbestos - but it just can't be had, so we try for the 'best' available, with varying results, depending on price, cost, expectation and availability.

Anyway, the main point being that I'd rather use a 'good' one with todays technology, than a 30-year-old GKN one which may have been incorrectly stored - but either will probably be better than something thrown together in Shanghai for 2 dollars a gross.... but only time will tell if it a valid arguement, the rest is pure conjecture.

[Simon_P]

... the rest is pure conjecture.

It is actually really quite well understood.

[Fredjohn]

Is there a book running on who will have the last word??

[Simon_P]

[Jeemy]

Compare the inner and outer gaiter, and ask yourself why they were designed so different, why the expense if Dave can by one that fits both. Many fit, some might last for a while.

Away from your healthy debate, you ask why they were designed so different, clearly rhetorically. I do not have pictures of an OEM inner and outer gaiter to compare, as clearly mine are the same thing found by others in search for an aftermarket replacement - it fits, but it isn't right. The garage round the corner are very much of the "measure inside, measure outside, measure length, fit the bugger" mentality. If there is more to it than this, I'd be interested to learn. Is there somebody who could post a little more info in my favourite format, picture form? (When uploads are fixed).

[tigerdog]

A few of us have used "Uni-fit" CV boots or similar. They are one piece, stretchy and actually go over the joint. I have one on one of Smaug's outer CV positions. It's held up well for the five years and (*cough*) 2000 miles it's seen.

http://www.dormanproducts.com/catalog/o ... sories.pdf