The Most Important Bolt On A '69 911?

[SIMI BOB]

Pretty sure I saw an old post by Grady Clay (on the bird) that he thought that the ball joint to the bottom of the strut on a '69 911 was the weakest link on the car and he would not ride in a car with this setup. So I took my ball joints off the other day (almost certain that the right front shock has never been off the car) and this is what I found. Apparently only one of these bolts was installed at the factory, because the right front was a DERA 10.9 and the left front just said 3 F 8.8, so not even the right grade bolt was used. When I pulled off the right front strut, I found the date code was 13-69, consistent with an April '69 build, but the left front was 33-70, so someone must have replaced the left front strut. Curious that this ball joint was misaligned exactly as the right front, and this bolt was also torn up. When they inserted the ball joint into the strut, they didn't align the cutout in the ball joint with the bolt hole in the strut, so part of the ball joint was protruding into the path of the bolt. This is the result. Luckily the threads in the bottom of the strut are OK, but when the bolt hit the ball joint, it tore the threads up.
See pic below.
Bob B

[davep]

A critical bolt to be certain. That is the worst kind of sloppy assembly I have seen recently.

[Phil Planck]

My theory is that Porsche intended for a shoulder bolt to be used there but thd assemblers had such a hard time aligning the bolt to the ball joint pin that Porsche changed to just a bolt that is undersized for the cutout in the pin. I tried to find one that would fit but found only one source I think in India. It was listed in catalog but not available. Closest I could find was in attached pic.

[SIMI BOB]

the assemblers should have at least pounded a drift in the hole to try and clear the hole! Not only did the factory screw this up, but a dealer mechanic that replaced the left shock did the same thing!
Bob B

[gled49]

They could of been assembled correctly, but that system had a tendency to loosen, and the damaged bolt could be caused during disassembly, after the ball joint pin rotated in the strut. I would inspect the threaded part of the strut for damaged threads which might tell you whether it was assembly or disassembly. Then I would throw the strut and ball joint away and replace them with the wedge pin style struts.

[lopena]

Since I have a ‘69 911S this thread definitely got my attention. I need to understand this better so I can check my own car.

In the attached PET page are we talking about bolt #18? If so, how do I check my bolt? Simply remove it and inspect it?

Will one of the experts here chime in and help me work through this?

Many thanks indeed!

Alan
N.J.

[Phil Planck]

Yes. I think torque spec is 33#'. Manuals have spec and frequency of checking.

[gled49]

If those parts start working/moving even with a tightened bolt, you will see distress between the pinch part at the bottom of the strut and the ball joint pin, even rust sometimes. Start by trying to move the bottom of the strut at the ball joint, and observe movement. Remember the bolt is trying to pinch the ball pin in the bottom of the strut.

[SIMI BOB]

Since I started this, let me jump in here with a few more pics. The first pic shows a close up shot of the ball joint stem. You can see that the bolt has rubbed here on both joints, one a lot worse than the other. As Gled has mentioned above, the damage to the bolts could have come at dis-assembly, but I can tell you that both of the stems of the ball joints had rotated in the strut, or had been very sloppily assembled in the first place. As you will see below, the left front strut had been replaced at some point. The bolt on the left has probably never been off the car (right front) and is a DERA 10.9. The bolt on the right was replaced with the strut and is marked 3F 8.8, not even a grade 10 bolt. Just wondering why Porsche didn't take some measure to make sure that this part did not rotate, maybe a shoulder bolt as mentioned above?
The more I get into this front end, the more I see that the left front wheel had been hit at some time. The car is an April '69 build. I bought the car in December of '74, and the left front strut has an August 1970 date code, then the damage happened sometime between late '70 and late '74. Take a look at the Tie Rod on the right, and you will notice that the Joint Fork is bent at the threads, obviously some un-repaired damage from the hit.

[stretch]

I swapped out the bolts on my 70 car with 10.9 graded stainless steel bolt with a lock wire. Belt and braces.