New MINI Suspension failure
New MINI Suspension failure
Author
Discussion

LotusBob

Original Poster:

6 posts

202 months

Saturday 26th May 2012
quotequote all
Is anyone aware of a weakness in Early New Mini rear suspension control arms?
They failed on my 53 plate CooperS nearly causing a roll.

Dave Hedgehog

15,294 posts

221 months

Saturday 26th May 2012
quotequote all
its a mini adventure biggrin

Defcon5

6,399 posts

208 months

Saturday 26th May 2012
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Are they supposed to be straight! DO you often transport a car full of fat women?

m8rky

2,090 posts

176 months

Saturday 26th May 2012
quotequote all
Slightly off topic but had a 55 plate Hyundai Coupe in my friends garage last year with a N/S balljoint sheared after hitting a pot hole due to heavy corrosion of the suspension arm.
Makes you wonder if safety standards are not so rigourous these days.

fareaster

234 posts

196 months

Monday 28th May 2012
quotequote all
I don´t know the circumstances of the failure but looking at the photo the impression is that some sort of excessive compressive load has been applied along the axis of the arm to cause it to buckle like that.
As far as the Hyundai balljoint is concerned, again without knowing the full circumstances of the failure, it’s difficult to understand how a corroded suspension arm could cause a balljoint failure. What can happen is that the rubber garter becomes damaged allowing water etc into the joint, the ball surface starts to corrode and pit, the articulation torque then rises resulting in a fatigue failure at the neck of the ball.
Quality standards in terms of the test regime and manufacturing process are much higher these days

Manicminer

11,787 posts

214 months

Monday 28th May 2012
quotequote all
Looks like it's had a sideways kerb to wheel hit at some point in the past.

I do vaguely remember something about these on early cars as I know I checked them on mine before I bought it (2001 Cooper). I had it 4 years and it's now with my brother and his family so will get him to check his to be safe.

The Wookie

14,169 posts

245 months

Monday 28th May 2012
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Not heard anything about the rears, although I have heard that the steering racks are quite sensitive to a bump

s m

23,960 posts

220 months

Monday 28th May 2012
quotequote all
fareaster said:
I don´t know the circumstances of the failure but looking at the photo the impression is that some sort of excessive compressive load has been applied along the axis of the arm to cause it to buckle like that.
Trolley jack in wrong place?

Fish981

1,441 posts

202 months

Monday 28th May 2012
quotequote all
s m said:
fareaster said:
I don´t know the circumstances of the failure but looking at the photo the impression is that some sort of excessive compressive load has been applied along the axis of the arm to cause it to buckle like that.
Trolley jack in wrong place?
That would be my guess.

Manicminer

11,787 posts

214 months

Monday 28th May 2012
quotequote all
Not sure why anyone would jack it there though???

anonymous-user

71 months

Monday 28th May 2012
quotequote all
They are actually supposed to fail like that !! Thats why you didn't roll!

If track control arms are made very stiff, they fail catastrophically, leading to the wheel/tyre tucking under and generally a roll. Hence they are made of steel, with pre determined failure mode. However, to fail like that, it will have been either:

1) previously hit sideways into a kerb (generally puts a little bend into the two members (they get a bit "bowlegged"
2) as mentioned ^^^ someones used a trolley jack under it and bent it


Once they have an inital little bend due to a prior incident 1 or 2 above, they then start to flex, and fatigue. Generally, some time later they then fail in a more noticable way, resulting in some pretty mad toe/camber angle on the wheel! But, the wheels does not become seperated from the car. hence you are still here to tell the tale ;-)


NelsonR32

1,775 posts

188 months

Monday 28th May 2012
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Damn those 12+ year old wear and tear faults!

TheEnd

15,370 posts

205 months

Monday 28th May 2012
quotequote all
Yea, they're the mechanical version of a fuse, they'll bend before anything else does.

One thing that's very likely to do that is being strapped down on a recovery truck with the straps over the arms.

They are sitting there in full view and look like easy spot to tie down, but it doesn't take much of a dent or buckle to get it started, and would do two of them more likely than each wheel being banging into something.

hyperblue

2,835 posts

197 months

Monday 28th May 2012
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I've never heard of them failing, certainly not a common problem!

fareaster

234 posts

196 months

Monday 28th May 2012
quotequote all
Max_Torque said:
They are actually supposed to fail like that !! Thats why you didn't roll!

If track control arms are made very stiff, they fail catastrophically, leading to the wheel/tyre tucking under and generally a roll. Hence they are made of steel, with pre determined failure mode. However, to fail like that, it will have been either:

1) previously hit sideways into a kerb (generally puts a little bend into the two members (they get a bit "bowlegged"
2) as mentioned ^^^ someones used a trolley jack under it and bent it


Once they have an inital little bend due to a prior incident 1 or 2 above, they then start to flex, and fatigue. Generally, some time later they then fail in a more noticable way, resulting in some pretty mad toe/camber angle on the wheel! But, the wheels does not become seperated from the car. hence you are still here to tell the tale ;-)
Generally track rod control arms and similar suspension components are steel pressings or forgings but its also quite common to see aluminium forgings on the exotica.
I have often been amused by the explanations given for a "vehicle leaving the road". On one occasion the son of the owner of the car claimed that while cornering the tie rod broke causing the very expensive accident. Maybe his father believed him but I certainly didn´t when I examined the components - it was quite clear that the vehicle left the road and the tie rod broke as it over articulated when it hit a kerb!

HustleRussell

25,705 posts

177 months

Monday 28th May 2012
quotequote all
Dave Hedgehog said:
its a mini adventure biggrin
Usually I disagree with you on pretty much everything, but that is funny hehe

scotty_d

6,795 posts

211 months

Monday 28th May 2012
quotequote all
NelsonR32 said:
Damn those 12+ year old wear and tear faults!
Who taught you to count 53 plate= 12+ yeras old hehe


I have a 53 plate cooper S and i had it on my ramp a few weeks to stone chip it and can confirm the rear suspension struts were in good order.

Marquis Rex

7,377 posts

256 months

Monday 28th May 2012
quotequote all
Dave Hedgehog said:
its a mini adventure biggrin
rofl

s m

23,960 posts

220 months

Monday 28th May 2012
quotequote all
Fish981 said:
s m said:
fareaster said:
I don´t know the circumstances of the failure but looking at the photo the impression is that some sort of excessive compressive load has been applied along the axis of the arm to cause it to buckle like that.
Trolley jack in wrong place?
That would be my guess.
Vauxhall Cavaliers were on Watchdog some years back with a similar issue at the front end