Mike Goebel

Gee let’s see if anyone knows the answer to that question. 🤔. Actually it’s intuitively obvious to even the most casual observer that the testing was done after testing in a zero gravity environment. 😂

Mime G.

SeaCay

How much and where did you find them?

There has been an issue with early spindles failing on the track, haven't heard the same for late spindles.

Droops83

Yes, I have personally witnessed an '86 951 spindle break in Turn 10 at Laguna Seca---not an ideal place for this to happen! Luckily the driver and car were OK.

I am not 100% sure of this, but I do not think the M030 spindle is any stronger than the regular '87+ version, it just has the mounting bosses for radial-mount brake calipers.

And please disregard my earlier comments about the 944 spindles possibly being made of ferritic stainless steel: I was digging through my parts stash yesterday and found some fairly rusty 87+ spindles

Penguinracer

Brand new M030 spindles from Porsche were £3400 for the pair - approx $US4800.

SeaCay

That's one hefty insurance premium...

Oddjob

The spindles are a forged carbon steel alloy. They do rust, from experience, but not heavily so likely there is chrome or nickel in the alloy. The specific grade and heat treat specs were likely considered IP by Porsche and maybe hard to find official documentation. Could have the material tested to get the alloy breakdown and the surface hardness on the spindle, but isn't worth the cost of doing so. It's machinable and won't be any issue for any experienced machine shop to bore for a 19mm ball joint pin.

I always had reservations about boring out the knuckle for 19mm pins as it could potentially make the knuckle more prone to failure. For that specific reason I went with Fabcar Arms (17mm pins) instead of Charlie Arms 15+ years ago. But I haven't heard of many/any failing over the years. So seems my fears were unfounded.

The 87+ and M030 spindles are basically the same dimensionally, use the same bearings, spindle is the same - other than the caliper mounting. They are beefier than the 86 spindles. The 86 spindles and control arms (the arm itself, not just the ball joint) have had known failures.

Mike Goebel

Is there documentation stating forged? Seems like they would be cast?

Mike G.

MAGK944

Yes I’d like to see that too. Having seen early spindles fail and also a later early offset spindle without the hole fail, they don’t fail like they are forged and the fractures look like a casting to me but I’m not expert.

If the M030 are different and are actually forged then that’s a big plus.

Oddjob

Well, the knuckles say "JECO" on them, which was a German forging company. They look like a die forged part, and certain features like the ball joint pin split clamp would be high risk if made from a casting (more brittle).

If you google something like "shaft fatigue failure" you will find plenty of pics of 1045 or 4140 shaft failures. There is usually a granular appearance across the surface of the fracture. But I'm not sure what all the parts you saw looked like.

MAGK944

Interesting, yes they exclusively dealt with forgings. I also heard JECO supplied forged pistons to Kolbenschmidt back in the day. A little snippet that stuck in my memory from a while back.

Mike Goebel

Geez if they exclusively did forging then I guess they’re Forged. However that’s a pretty complicated part to forge. The other thing that’s strange is the surface is pretty rough for a die forged piece. But on another note what looks to be the parting lines are pretty wide which is typical of a forged piece instead of a cast piece.

Mike G.

Oddjob

I had a set of M030 spindles mag particle inspected about 15 years ago before installing on my track car. I looked for the test report in case anything about the metallurgy or type of manufacture was stated in the document, but I couldn't find it in a quick search of old files. I'll look again when I have more time.

sm

What is a respected shop to get the inspection done? I have m030 spindles that I want inspected. Thanks

Jay Wellwood

Just do Google search to find a Quality NDE company that offers these services. A company that advertises having a NRC Appendix B Quality program will be top notch and have all the right qualifications in place to provide the highest assurance that the testing is done correctly by competent people.

s85b50

Does anyone know the ball joint pin size for M030 spindles? Looking at control arms with 17mm pins..