Damian in NJ

I wasn't pointing fingers; in fact, had you read the quote from Karl of Racer's Edge, this seems to happen pretty often, regardless who prepped the car. Am I correct to assume that there are 'race spec' pins that should be used for racecars?

H2OJazz

If he had been hurt it would have been the foremost part of my post. The driver is a friend of mine - that was my first concern after the incident.

968workaholic

I just wanted to let everyone here know that he is fine. It just seemed to me that the conversation in this post never brought up the question if the driver was ok. Did not mean to offend anyone.


The ratio of arms in use and failures of those arms is small, so I wouldn't consider it an often occurance. Compare it to a timing belt failure. When the belt fails who is to blame? Porsche for not making the changing interval sooner? The manufacturer of the belt for making a product that couldn't withstand the service interval? The driver for not checking it/driving it hard? Same concept different situation.

Lemming

I don't have access to the other site, who was it! Eric? Regardless, I'm glad that they walked away from the accident.

As for the failures, that's one reason that I'm glad I run the old steel arms and pins that I replace on a yearly basis.

93 FireHawk 968

I can tell you I replace my pins every 2 seasons. I've broken both sides at different tracks despite very careful inspection during frequent servicing. I still run stock arms.

Now with that said, my car is track only with an aggressive set up that's driven very hard when compared to a street car.

SpeedBump

That is a very wise move and cheap insurance

Eric_k

I'm one of those that had a pin fail. Luckily just bent the fender and the tie rod. I replaced the pin & tie rod and was racing the next day. Others have not been so lucky. I believe mine failed because of undetected damage from previous incidents. The crack was were the pin is indented for the spindle bolt. It is inside the spindle and would only have been visible with disassembly. I should've taken it apart but didn't. There are no warning signs - until snap! Mine was a Charley arm but the others were Koklen and Fabcar so obviously this is a highly stressed part, no matter the manufacturer. Removal and inspection of the pins is good policy.

wonko

Just to clarify the discussion on 968 Forums:

1. This failure has happened on multiple vehicles.
2. It has happened on multiple manufacturers A-Arm pins. There is no particular manufacturer to point at.
3. I am not under the impression that these are cars that have been lowered to obscene levels.
4. Two of the failures obviously occurred over time and across several incidents based on the pattern in the breakage.
5. The breakage occurred within the spindle, thus making a visual inspection useless without removing the pin.
6. No matter what we do, something will take those stresses. Beefing up the pin will just move the stress to some other, most likely more expensive, part. So modifying the parts themselves does not seem to be the answer.
7. This has not previously been stressed as a weak point, and thus a vigorous discussion is warranted to both address the problem and also get the word out.

I have come to the conclusion that annual replacement and a thorough inspection (read remove from car) after any significant impact or off that jarred the suspension harshly is a reasonable routine. Discussions of alternative regimes would be warmly welcomed.

These are relatively cheap parts that can, and have, totaled cars if they break at the wrong moment. This should be easily addressed, the question becomes what is too often, and what is not often enough. Until there is more data, I don't think we really know the answer to that and should proceed with appropriate caution.

As the discussion began on the 968 Forums, I would invite further discussion to continue there.

http://www.968forums.com/index.php?showtopic=6275&hl=

John

Jason Judd

[B][I have come to the conclusion that annual replacement and a thorough inspection (read remove from car) after any significant impact or off that jarred the suspension harshly is a reasonable routine/B]
_______________________

That sounds like sound advice...I'm going to add 'pin replacement' into my yearly winter list of things to do...just like rod bearings. And I already have Karl's upgraded 19mm pins from Kokeln.

Jason

Peter Empson

I had a pin shear last year at Brands Hatch in my 944 and was very lucky that it failed where there was a large gravel trap to stop the car http://myweb.tiscali.co.uk/944lux/Balljoint.html, it's very sad to see that some others haven't been so fortunate.