911 (996) ball joints keep breaking

[catahoula lou]

My neighbor has a 911 (996) in which the ball joints keep breaking. He thinks it's because of the circumferential groove that is cut into the base of the shaft, creating a weak point.

Is this common and how to prevent future breaks?

Best,
Thom
_________________
1 great wife
2 Catahoula Leopard Dogs (Mahogany Star and Spartan) - RIP Lucy, Braveheart, & Dusty!
1 1959 mango green Ragtop Bug (the "Mango")
1 1958 pantina red Lowlight Ghia (the "Chili Pepper")

Still looking for:
(1) My Dad's 1955 356 (he raced it amateur-class at Riverside and other courses during 1950s),
(2) My parent's black 1955 hardtop bug (CA license plate FWC 201 or FWG 201), and
(3) My parent's agave green 1957 ragtop bug (CA license plate LFK 734).

[raygreenwood]

No......that is most definatly not it. Highly doubtful.

That groove is there to prevent a stress riser and also to make clearance between the swaged edge at maximum lock which really should never happen

So he thinks its the joints? If there were a bad batch...anything is possible....but as vocal as Porsche owners are....a simple search....and I did one.....would find a rash of them.

The items that snap the stud off of ball joints are like this:

1. Excessively re-tuned suspension....meaning.....staying with a stock quality ball joint when going to highly uprated springs and shock dampers.....along with very low profile tires.

Ball joints....most of them....have either a full ball or half ball design in a hard, self lubricating plastic packing cup backsd up by a stiff spring. When you go to harder springs, struts and tire sidewalls each takes a portion of give or flex out of the system. So hitting hard bumps....transfers more force the final flexible link in the chain.....the spring of ball joint.
It bottoms the spring an repeatedly slams the joint and usually does one of two things...usually both......it hammers the outer swaged lip that keeps the ball stud in the socket. In a really strong ball stud design the ball stud will not break....but instead the entire stud is at risk of pulling out of the socket. At other times it fractures the stud.

2. If the suspension has been uprated as mentioned....and it has excessive castor....great for steering to get rid of tram-lining from wider more aggressive tires.....it simultaneously results in a sharper angle to the ball joint and also transfers more force from hard bumps laterally.....which can snap the stud off.

3. If the tapered pin of the ball stud is not swaging into the tapered bore at the bottom of the strut...essentially making them one unit.... either because the tapered bore is worn or damaged or the tapered pin is damaged or one or the other has rust or debris.....the pin will rotate inside of the tapered bore instead of the ball rotating inside of the cup. This damges both parts and can snap the pin.

4. If the ball joint is not mounted hard to the control arm....and just going off memory....these are threaded into the arm?.....movememt, vibration and misalignment can damage the joint and snap the stud.

5. If the joint runs out of grease.....it can snap the stud when it siezes.

6. If any damage to the outer bwll joint casing has happened....it csn,sieze the ball and snap the stud.

7. Lastly.....if as mentioned above....the suspenion has been upgraded...especially with urethane or delrin control arm bushings....and urethane or competition upper strut bushings....along with other items like springs or dampers.....each takes a portion of give or spring out of the force chain. The ball joint is the weakest link.

Find out a bit more about the rest of his suspension and how it is being driven. You noted that he "keeps breaking" ball joints. That is not normal and a repeated pattern says something.
If his suspension is not normal.....uprated...racing....track days.....you need to uprate the ball joint as well. Ray

[Starbucket]

You race it, you break it, you pay to fix it. Drive it as designed and you will be a happy Porsche owner and save tons of money.

[catahoula lou]

Thanks, Ray. Will pass your information on to my neighbor.

Best,
Thom
_________________
1 great wife
2 Catahoula Leopard Dogs (Mahogany Star and Spartan) - RIP Lucy, Braveheart, & Dusty!
1 1959 mango green Ragtop Bug (the "Mango")
1 1958 pantina red Lowlight Ghia (the "Chili Pepper")

Still looking for:
(1) My Dad's 1955 356 (he raced it amateur-class at Riverside and other courses during 1950s),
(2) My parent's black 1955 hardtop bug (CA license plate FWC 201 or FWG 201), and
(3) My parent's agave green 1957 ragtop bug (CA license plate LFK 734).