Checked your balls lately?? Ball joints, that is...

[dtfastbear]

So I came out of turn 6 at Infineon Raceway and head down the short straight, and I notice that my steering wheel isn't quite straight. I slowed way down - the car felt really darty, but there was nothing loose in the steering and no vibration. I drove in at about 40 mph to the pits. Here is what was wrong:





My mechanic said he's never seen a ball joint cracked like this before. There is some oxidation in the crack, so it must have been cracked for some time. I didn't hit anything hard (like a curb) during that track session.

I feel pretty lucky that I noticed it on the straight. I don't think it would have made it through the esses...

Dean

[Grady Clay]

Dean,

WOW, that is as close to biting a high speed bullet as I have seen in a long time.

You must not have read these threads in the past weeks:
What are signs that the ball joint needs replacing?
and
Long term & Commonly Neglected Maintenance

Please have a professional forensic engineer analyze that failure and post the results here. If you need help with the cost, say so. That is an absolutely frightening failure.

Best,
Grady

[azasadny]

Dean,
Wow, you're lucky!!

[Randy Webb]

So, what happened to your balls when you saw that? just estimate the shrinkage to the nearest 10%

[djmcmath]

Thank heaven you survived -- that could have been a nasty out-of-track experience.

Question: how did you spot it, without removing the ball joint from the strut? Seems like, because of the way it's constructed, that it'd be tough to catch that on anything like a "routine" inspection.

TIA,

Dan

[RoninLB]

not uncommon when slamming huge NYC pot holes.. although I've never inspected a broken one.

[dtfastbear]

Hey Grady - where might I find someone to analyze it and what would I expect in the way of results? What would we learn from it?

Randy - the pucker factor was quite high! It's got me thinking seriously about trading up to a full on race car with a full cage. We've got a cab with a roll bar, now...

Dan - I didn't find the problem at the track. I couldn't find anything broken or bent, although it was obvious that the front wheels were toed out a little bit. I figured it was something inside the steering rack. I actually drove the car home from the track (only about 10 miles) at no more that 60mph. I'm even luckier that it didn't break on the street than on the track, as I'd have been more likely to get hit by another car.

We spotted our mechanic's car outside a bar on the way home. So, I sent my wife in... after a "penalty shot" of Jaegermeister, she had the keys to the shop so I could drop it off

The shop found it. The mechanics keep saying to me, "Man, you had someone watching over you, you lucky bastard."

Dean

[djmcmath]

That's fantastically lucky. Now I'm paranoid -- I feel the distinct urge to set up a routine schedule for dismantling major portions of my suspension to inspect for impending doom. That's just amazing that it didn't fail on you!

Dan

[Grady Clay]

Dean,

Look up “Engineers – Forensic” in your yellow pages, there are 20 listed here in Denver. Do an on-line search. Find a local guy. If he doesn’t have to write a report or testify in court, it probably will be free.

It looks like the break is just there the pin comes out of the strut. I will speculate that the wheel hit something sometime in the past and severely bent the pin. It must have changed the alignment. The alignment tech simply compensated (maybe) by adjusting the camber and toe settings. On the tension stress side of the bend, a crack started and progressed to the state you see. You are one lucky dude.

I would check the strut and A-arm also. Take the strut to a dealer that has P-286b and P-284b for the strut and spindle and P-288b for the A-arm. You might find other damage in the tie-rods, steering or cross-member.
You certainly will find the alignment way off. I would replace the other ball joint also.

Are both front wheels identical (date stamps, etc.)?

Do you have PO repair info? What can CarFax tell you?

Best,
Grady

[Zeke]

That cemeted the idea of ordering new ones while I'm doing my suspension. Mine are perfectly good.............for now. Anyone want to buy some used ball joints?

I didn't think so after reading this.

[Chuck Moreland]

How many miles on that part? How many track miles? Autocross?

This is a reminder that parts do fail and that regular inspection is important for cars that get tracked.

So is periodic replacement of critical parts. Serious race teams replace parts after xxxx miles/hours even if they appear perfectly fine.

Maybe we need to work up some guidelines for tracked cars; recommended maintenance and replacement interval for critical parts. See also the current thread about a bump-steer kit failure.

I'm thinking specifically about critical items that lead to loss of control;

- ball joints
- tie rods (and add-ons like bump steer)
- struts
- tire valve stems
... what else

[Grady Clay]

I absolutely agree with Chuck, there are some parts on a 911 that you just summarily replace. The only issue is how often is appropriate considering the use and conditions.

Chuck said; “I'm thinking specifically about critical items that lead to loss of control;

- ball joints
- tie rods (and add-ons like bump steer)
- struts
- tire valve stems”
I’ll second those and add:
- Brake master cylinder, hoses, and caliper seals.
- Just this week we were discussing CV bolts and Schnorr lock washers.

“There is no Substitute” for careful inspection of all 911s, track or not. You are just as dead if a ball joint fails and you are thrown into oncoming traffic. The 18-wheeler might not even notice a 911.

When I say careful inspection, I mean THROUGH careful inspection. I once saw a 911 that had had new struts, ball joints, tie-rod ends, wheel bearings, shock top mounts and more (even rear shocks, rear wheel bearings and axle assemblies) from a shop chasing a driving problem. One mounting ear on the steering rack was broken off and the other loose – they had never removed the pan and looked. All they did was to sell the owner more parts.

As our 911s age, more people have had their hands on them. More aftermarket parts installed, properly and otherwise. And just plain use and age.

To the above list I would add:
- Previous improper repair, maintenance, or installation.

The ball joint on this thread, the failed “bump steer kit” on another, and many more tell us this is a serious issue.

Best,
Grady

[dtfastbear]

So, I am one lucky dude. My strut (same side) broke at the track today.

I had new ball joints put in on both sides and new strut inserts (bilstein sports). I have Boge struts, just for the record.

The strut housing cracked all the way around just above the spindle. I'll take pictures of it tomorrow. My wife had just come off the track - she didn't mention anything feeling wrong. As I was leaving the pit entrance, the steering "got funny" on me. As I went through the first turn, I knew something was wrong. I slowed to about 30 mph and drove the rest of the way around the track. The whole thing started to vibrate, and it felt like the front end was going to come apart.

When I jacked up the front end, the entire wheel could just be shaken by hand - the entire strut was cracked.

I trailered the car home and disassembled everything. It turns out the big nut on top of the strut body that hold the insert in was not even finger tight. When I went to remove the nut on top of the strut insert, I noticed that the two bolts holding my front strut brace were not tight - one was about 2mm from even being screwed in all the way. I have a weltmeister strut brace, so that positively locates the top of the strut insert. Do you think that the forces in the strut brace moving the top of the strut insert back and forth would have hastened the cracking of the strut body??

It looks like my mechanic never really "finished" the job when installing the strut on the drivers side.

Man - I feel really lucky that I dodged another bullet on the track, but I'm pretty pissed off at both my mechanic for leaving all this stuff loose. But, ultimately I'm pissed at myself because it's MY responsibility to check the car out before heading out onto the track...

Grady - I think you must be right that this left side took a serious shot at some point, either breaking, cracking or weaking all the suspension pieces. I've had the car for over 4 years and have put about 70 track days and 75 autocrosses on it.

I'll consider taking the ball joint to a forensic engineer after I get my car back together!!

Dean
Dean

[Grady Clay]

Dean,

After you replaced the ball joints, how far did the alignment have to be adjusted?
Was there a significant difference L-to-R? That might be a clue.

I would very carefully inspect all the other suspension & steering components.
Additionally when they are off the car, inspect the chassis mounting points for cracks.

Most competition struts have a pair of triangular reinforcement between the spindle and the strut tube.
This distributes the stress on the tube.
In the image, white outlines one of the reinforcing gussets.
The other is on the opposite side of the tube.
They are welded to the spindle at the bottom and to the tube at the left in this perspective.
It is not welded at the 90 degree corner and the corner is notched to prevent crack propagation.
They appear to be TIG welded.
Perhaps we can get Pelicans rs911t and pwd72 to photo their original RSR struts.

While you have all this apart, it is an opportunity to change the position of the spindle on the tube.


"
"
(C) Dr. Ing. h.c. F. Porsche A.G.


Here are the dimensions for the cross member.
When you have everything un-mounted from the chassis, try
and test-fit just the cross member to the four mounting points.
It should fit without force.

"
"
(C) Dr. Ing. h.c. F. Porsche A.G.

I would consider dissasembling the steering rack for inspection (Magnaflux).

Best,
Grady

Edit for (C) and typo.

[mb911]

I will be buying some new ones over the winter