H2OJazz

I would encourage folks to check out the thread on that other 968 forum re A-arm failures. A good friend of many of us had a catastrophic failure recently. This is especially important to those of us who track our cars.

Peace

H2OJazz

Further clarification - pin failure

Techno Duck

http://www.968forums.com/index.php?showtopic=5441&st=40

Damian in NJ

Would a thorough inspection prior to the race shown the fault? Is that something that could have been missed?

SpeedBump

No, and it was not just one person with the failure there have been multiple occurrences.
You could just go read the thread, it's not like you have to pay anyone to read it.

Luis de Prat

Haven't read the thread, but I'm guessing these cars were lowered. IIRC, that's a no no unless you fit billet arms like Charleys.

SpeedBump

At least one of the failures was with Charley Arms

Damian in NJ

I guess if this has been at all a common occurence that the people prepping these cars would have anticipated the problem; the fact that it has happened over and over again is kind of frightening. Porsche did recommend that you don't 1) lower the cars too much and 2) don't fit 18" wheels-so if you're prepping a car, and do those things, then watch out.

PorscheDude1

Discussion on Pin failure with pics.
http://www.968forums.com/index.php?showtopic=6275&hl=

RajDatta

Were the failures all ball joint failures? If so, the tech has to be held responsible. There are plenty of warning signs before the ball joints fail.
If the failure is with some other part of the arm, the manufacturing has to be questioned.
Raj

PorscheDude1

True, if you are running stock a-arms and castor blocks.

Damian in NJ

This is from Karl Poeltl of Racer's Edge talking about the same thing.

am aware of 3 A-arm ball joint/pin failures that happened at Road Atlanta. All three were on cars from the Chicago region. All three were ball joint pin failures. Shawn’s was a factory arm; the other 2 were Fabcar arm pins. Shawn’s Pin failed at the groove that goes around the pin that the spindle retaining bolt goes through. This is a very common failure. I have had 2 of this exact failure happen to me, one on a 4 month old set of arms. In both of my 2 cases and also in Shawn’s case, the failure happened due to the fact that we caught the back side of a curb and the wheel got "caught" on the backside of the gator and pulled outward at the bottom as the car slid across it. The other 2 Fabcar pin failures both occurred in the esses at Road Atlanta. The pins failed at the section of the pin where the large diameter taper radiuses to the 17mm section of the pin.

Karl Poeltl

968workaholic

I am sure Porsche also doesn't reccomend turning a 968 into a full out race car either but that is besides the point right? Lowering the cars too much will break a factory control arm, due to the geometry being wrong. But when installing an aftermarket arm with geometry correcting pins, no more issue.


What are these signs of a failing ball joint that you speak of? The only thing that I can think of is a small amount of play, which is called a WORN ball joint not a FAILING balljoint. A FAILING balljoint will just break, no warning signs. Also, the incidents listed were caused by pins breaking, not ball joint failure. Unless someone devlopes X-Ray vision to look at the pins to detect internal fracturing, please share, otherwise accept what happened as an unfortunate accident, and resist the urge to point fingers because a piece of metal broke.

LTCMontana

Workaholic,
I agree 100%. Questioning Porsche's designs when people are stressing them far beyond the specs shouldn't be called "suspect." It should be called carelessness.

Has anyone heard of a failure on a street only car?

On the other hand, it is VERY useful to get the word out that these guys have found a weak link and we should all heed the warnings.

968workaholic

Also, for all interested parties the driver walked away without any injury. Seems like the wrong part of the incident got all of the attention.