MistaX

WELL this happened.

Are all spring plates the same? There's a few 951 sets on ebay right now, will they fit my early car?

Wasn't planning on swapping torsion bars this year, but now I guess I have to... while I'm in there.

V2Rocket

holy ****!
did you jump it?

get an "early car" replacement part, im pretty sure the spring plate changed to accomodate the aluminum arms of the late cars.

Dougs951S

Wow. Every time I think I've seen everything, I see some new failure I didn't think was possible. Bravo sir. I bet the handling got interesting when that let go.

MistaX

No idea how it happened. Drove car, was fine, parked it. Went out again a few hours later, was broken, undrivable.
When I had the car aligned a year or so ago, it was pointed out to me the plate had a minor, years old crack, and that it "might fail eventually" so this isn't entirely unexpected.

Crab walked wondering why I had to hold the wheel 90 degrees to go straight. Honestly thought it was a front suspension issue until I saw the passenger rear with like 5 degrees positive camber.


Ordered the plate, ordered 30mm torsion bars, now just need to educate myself on what mounts and bushings to get.

thomasmryan

The spring plate bolt pattern is slightly different than the aluminum trailing arms.

Chuck at elephant has normal and sport harness spring plate rubbers for your new plates...cheap or the poly bronze things which are not. Your bar looks pretty well centered

I would replace the lock nuts.

No matter how much I mark everything, it takes three indexing sessions to be satisfied. There is a good pdf on doing the math on a bar diameter change using diameter ratios.

When you get it dismantled, post a picture of the edge/break.

MistaX

Before I order, I want to be entirely certain of every part that I should/need to replace in this project.

So here's the shopping cart:

Polybronze spring plate bushings
477-501-069-A end cap bushings Edit: Is this the solid replacement for that?
Solid torsion banana arm mount
Solid torsion bar cap to frame mount
Monoball trailing arm pivots

Am I missing anything?

mikey_audiogeek

Wow! Reminded me of this:
https://metallurgyandmaterials.wordp...ship-failures/

Dougs951S

ah yes, I remember being lectured in depth about the liberty ships in one of my materials engineering classes as a prime example of how NOT to design things with respect to stress concentration factor, and also about how temperature can play a huge role in ductile vs brittle failure of a material. We also spoke at length about the De Havilland Comet. I wonder what the underlying cause was in this case. The aluminum should not have been under enough stress to cause it to plastically deform and work harden, so it must have been a fatigue related failure I'm guessing?

mikey_audiogeek

My guess is someone cranked on the camber adjuster without unloading the suspension or loosening the other two bolts.

This would have loaded the edge of the hole and created a high static tensile stress - ideal conditions for any cyclic stress to initiate fatigue.

Cheers,
Mike

shortyboy

Got a pair I can sell. Lmk -Wayne

MistaX

I'll take more pics when the carrier is entirely out of the car.

I can't physically push down on the plate and get it to move back to position, but I can move it side to side easily.

tempest411

I wonder if this has happened to any of the 911 guys?