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Sheared off lower ball joint
A bad thing happened today. I was Autocrossing and the lower ball joint
sheared off and then the upper ball joint pulled out (left front). The wheel (wheel, rotor, hub) came off and did a lot of damage to the body. Has anyone had this happen? Not looking forward to get a price to repair the body work. Thanks, KenM 2560 |
sorry to hear that. were you in atwater?
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Keep us posted. -- weld failure >?
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I was running in Marina.
The lower ball joint stud sheared off. The remainder of the stud and the nut are still in the spindle. I talked to Dennis today and he has never seen that happen before. He is checking on it. Not as worried about the parts as the body. The parts can be replaced, don't know what it's going to take for the body. Thanks, Ken M 2560 |
It is entirely possible that the loading of the front suspension while in a turn caused it (the lower control arm) to exceed the design angle of movement causing it it fracture? Otherwise you would have had to impact something with the tire/wheel to create a shearing force (unlikely). Did it fracture right next to the "ball"?
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parts information
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Barry Bloch General manager Superformance LLC. |
Ball joints just don't break! It's possible that there was a whole bunch of defective ball joints in their production run. I hope the company (SPF) investigates this problem and identifies who else may be in jeopardy. It's better to be safe than sorry.
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Pictures
This should be a link to the pictures I posted. First time so I hope it works.
http://photobucket.com/kenm2560 I was almost going straight and I did not run into anything. Honest, this was not driver error. It was not binding when checked the day before. Thanks everyone for the concern, I am ok, just upset about what happened. Working to get the car running for the next event. Thanks, Kenm2560 |
I'm no metalurgist, but I've seen failures like that in aircraft parts. The just flat assed failed. It looks like the sheer load exceeded the capacity of the material. That means that either the heat treat was missed or insufficient or that the forging alloy was wrong. I'd be more inclined to look at the heat treat.
At least I'm glad you weren't hurt.. |
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Ken, sorry to hear about your misfortune and I hope things get patched up quick so you can be back on the road! -Dean |
Ken, get it patched before the 21st of June. I'd like to hear about it first hand at breakfast.........Where ever it's going to be..........
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Yea, pretty bold statement. Like you Dan, I have some pretty extensive experience in the airline/aircraft industry. I know of at least one instance where the nose gear on an MD-80 failed. Boeing/MD just said that it looked like metal fatigue and appeared to be an isolated incident. It has not happened since, to my knowledge, and no service bulletins were posted either. Sometimes things just happen based on the series on events that precluded it.
Neither the airline or the manufacturer were found to be at fault and it was determined by the FAA to be an "unexplainable isolated incident of metal fatigue". Just glad you are safe (as were all of the pax). |
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If you look at the 009.jpg picture you can tell that this condition has existed for some time. The final failure happened when the dark gray area failed. The lighter gray area had been cracked for some time. It appears to me that it failed right at the transition to the threads. Is that correct?
And don't feel bad. The chances are that a casual inspection would not have indicated the condition so you did not do anything wrong I would recommend that all ball joints be replaced. Could have been a bad batch. or an isolated condition. |
I have not taken out the part of the ball joint stud that is still in the spindle yet. I don't think it is right at the transion.
There were no signs of the problem, I checked the car over pretty good. Just put the shock back on and eveything looked ok. I agree all the ball joints should be replaced. Quote:
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Have you looked at the possibility that the upper joint failed first causing the break at the lower joint and tie rod as wheel snaped back? Just a thought, but if the lower joint was tight and correct taper it should not have sheared like that. The start of the threads should be higher on the stud, so the tapered sholder is what is contacting the spindle hole.
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In my opinion there's no way that part should have failed even with the most severe duty. I believe that if you were to check the hardness of the part you will find that it was either heat treated improperly or that during use lubrication wasn't able to get to the part and it work hardened and failed. If this was a part that was supposed to be "lifetime lubricated" I think a lack of or insufficient lubrication from the very beginning is your culprit. If you have access or live close to a metallurgical (SP) lab I would have them perform an analysis to find out for certain what the cause was.
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Maybe it's just a car, but I would not want it to be mine. I agree with the statements regarding heat treat and general manufacturing quality. These parts are made to survive a vehicle lifetime and usually wear out before failing in the field. Maybe if the car hit a concrete abutment or a sinkhole would it shear, but not under normal driving conditions. I wonder who the manufacturer was? If I had an SPF Cobra, I'd change all four ball joints and replace with Moog parts. |
Yea, I think it's important to find out what happened and maybe test some of the failed parts from the same batch before running out and causing mass panic. One incident won't cause that, but it's still important to know what happened, if for no other reason than personal knowledge.
Now, if the incident does not end up being an isolated event... |
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Unfortunately my work days just went from 12 hours to 14 for at least the next few weeks. Hopefully I will have this Sunday off. If so, if no other engineer has chimed in by that time I will take a couple of your pictures and point out some things to you. If time allows I will have one of our stress engineers at work take a quick look at a couple of your pictures and see if he agrees with my analysis. |
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