Yesterday I experienced something that could have been much worse.

On my fourth session, I experienced a rear lower ball joint failure as I was entering a braking zone into a 29mph hairpin. The log shows that I reached 87mph and at about -.5G, the ball joint failed. So it basically failed immediately as I got on the brakes. The track isn't that wide; it is about as wide as a public road. There is approximately one lane's distance between the track and the wall on that turn. The good thing is that the failure didn't scare me enough to take my focus off of keeping the car safe. I felt the failure and then noticed that I basically had no brakes. I just veered off the track and into the infield section to avoid the wall. You can see in this circuit overlay where exactly the part failed.



That is the pit in and out turn as well. The right side is pit out.

And here is how the part failed:


And what the lower control arm did to the wheel:


I'm not quite sure what to recommend here. I have personally never been into that side of the car (well not as deep as separating the ball joints). A few of us suspect that the ball joint was installed using an impact or overtightened and the bolt stretched. I also suppose that it may have been loose. I have owned the car since July 2009 and done tons and tons of track days and hard driving; all of it has been on street tires. I guess all I can really say is watch out. All I really expect out of this car is to be a semi-nice car that can go to occasional track days and it has done that. I'm not disappointed in the car or anything. A lot of people will say "Go through every bolt on the car before tracking" and I do agree that that is a good idea, but unless you are using a micrometer to measure for bolt stretch, that may not have even worked here. So, if anything, I'm just sharing an experience and maybe raising some awareness.

BTW, I did discover through some searching that 1997 accord front lower ball joints are the same as our rear lower ball joints, You can press the old one out and press in an accord ball joint. I fixed the car yesterday and I'm rolling on a friend's AP2 wheels for now until I get one of my other RPF1's repaired.

31MAR2015-Updated with part number:

Moog K9643 Ball Joint

 

Glad to hear you're okay!

 

It was a control arm failure and not the ball joint, right? This goes on my list for regular replacement along with brake lines. Thanks for posting!

 

I think it was ball joint failure. looks like the threaded part just completely snapped in half.
but since there was nothing to hold the arm to the knuckle, it ended up hitting the wheel

 

That is correct. The only real question is whether or not it was loose or just overtightened.

...

Replacing them might not be a bad idea esp if you are going to be going for all out time or w2w (jumping curbs, contact, etc) on R compound tires.

 

Gotcha, I couldn't see the picture very well on the phone.

 

problem is trying to find a replacement.
is the 97 accord a direct replacement? or is there modification needed?


i would think that the ball joint was over tightened.
if it was under tightened, you probably would have heard it
atleast that would be my guess.

 

I didn't modify anything when I used the accord ball joint to replace this broken one. It seemed to be the same, but maybe I missed something...(??)

 

I agree with it being over tightened, lots of body shops just use impact guns on everything they can get a gun on.

 

I just replaced mine today with the 1997 accord front lower ball joint. Its exactly the same. Air hammered em out and back in. Took about 30 minutes. No modification needed to the ball joint.