WHAT THE F@%$#@ ... HOW DOES THIS HAPPEN?

[NullZwei]

FWIW, I just checked the official BMW 1502 - 2002 Repair Manual (blue binder) pages 31-12/5 through 31-12/7 and it definitely shows the ball joint being installed from the top just as the parts manual shows. It describes the repair for replacing the ball joint by drilling out the factory rivets and replacing them with SHR M8x20 bolts and nuts. I don't know what the SHR represents. It does not specify a hardness value for the bolt/nut but I'd use 10.9 if I can find them.

[Todd21]

Stainless is much more ductile than hardened steel fasteners. I'd bet the bolts stretched, leading to failure after joint separation.

One thing the add: the factory installation of the ball joint in the control arm is with the ball joint on top if the control arm. If the ball joint was on the bottom of the control arm the rivers would be in tension and would not work properly.

The blue book shows removal and installation instructions with the ball joint still placed on top of the control arm.

My car still has the factory units installed. They are on top of the control arm. I spent to day prepping two more control arms for new ball joints and bushings so this post was very timely.

Brother Zac, sorry to see you car get banged up but glad you are ok.

Todd

[02Les]

Morris Minor "trunions", (spindle uprights) are a 5/8 thread , they shear like a carrot ,always when turning slowly or parking!!

Ha...I remember back in the day (UK) you would often see a Morris Minor near a roundabout with a wheel missing. Also Triumph Heralds broken in two.

[Napes]

The bolt that c.d. references is for the pitman arm, according to both RealOEM and bmwfans.info. The ball joint bolts have this note in both RealOEM and from the BMW dealership:

Supersession Information

Part number 07119901120 was superseded by part number 07119903039

The MSRP for these bolts are $0.71 each.

Bob Napier

[boxy02]

For future reference:

"...... I'd NEVER use anti-seize on these threads....but I *DO* add a few drops of paint on top of the one hole that goes all the way through the strut base, to prevent moisture from entering the threaded hole after assembly. ...."

Hi Paul, Why wouldn't you use anti-seize in this instance? I'm just curious. Thanks,

Mike

[02again]

If all are safe and we can joke a bit. I would say it was probably the Flux Capacitor. It's failure can lead to a breakdown in the molecular resonance of the molecules associated with the strengthening bushings. (don't forget it IS saturday night)

[dlmrun2002]

Some people are sensitive to "dry thread" torquing. Maybe that's' why Paul doesn't use anti-seize. I'm a sensitive guy too. That's why I carry a gun. Sorry for hijack of thread Zack. Get your car back soon. I luv seeing that monster at Vintage every year.

dlm ny country

[dlmrun2002]

Some people are sensitive to "dry thread" torquing. Maybe that's' why Paul doesn't use anti-seize. I'm a sensitive guy too. That's why I carry a gun. Sorry for hijack of thread Zack. Get your car back soon. I luv seeing that monster at Vintage every year.

dlm ny country

[Todd21]

Hey Zac,

Babs says it was probably just bad Karma because you weren't carrying your ID. Ha Ha Ha....

Todd

[napa02]

For future reference:

I never....*NEVER* use stainless fasteners on load bearing / suspension/safety assemblies.

BINGO!, I have lots of stainless hardware on my car, never and I mean NEVER, would I use it on a load bearing application...

[harry6422]

I have read all the replies and it could be a combination of things, the bolts, wider wheels different offset than stock (more stress) ?. I pulled out my 2002 Haynes manual and on pg. 176 it shows the ball joint in the control arm mounted on top with the bolts fitting from the top and the nuts under the arm with safety wire . Should be interesting what you find on the other side.

Harry

[steve k.]

It's the bolts that hold the strut at the bottom. They are small and they have to withhold huge forces. You need to use the correct bolts. If you ever find one of them loose, replace it. As soon as they get loose they will stretch and eventually sheer. Your grade 8 bolts are not strong enough.

Once you lost the strut at the bottom, it just pulled the shock out. The bearing is supposed to prevent the strut from going up, not from being pulled down. The only reason mine still stayed in place is due to well set up spherical bearing.

steve k.

http://www.kgb-racing.com/component/option,com_gallery2/Itemid,29/?g2_itemId=469

[SteveJ]

It sucks!, but, at least you were there and not out on a high speed run somewhere.

I used to be sure to grease or anti-sieze almost everything when I first started dealing with rusted hardware. I have been leaning more towards the various thread locking compounds. Over grease, supposedly: they allow for lower torque settings (where allowed!), they do not change characteristics over time (gum up, dry out), they protect against corrosion within the threads, and allow for a more consistant break force for removal.

And they come in pretty colors- red, blue, purple, green.

[mooseheadm5]

Metric Grade 10.9:

Sigma(y.s.) = 940Mpa

Stainless 18-8:

Sigma(y.s.) = 551MPa

Ref: http://www.boltdepot.com/fastener-information/Materials-and-Grades/Bolt-Grade-Chart.aspx

Stainless is much more ductile than hardened steel fasteners. I'd bet the bolts stretched, leading to failure after joint separation.

This is precisely what happened. The stainless fasteners are only 58% the yeild strength of the 10.9 fasteners and less than 50% the yeild strength of a 12.9 fastener. A little bit of stretch in one bolt will cause the connection to loosen. Cyclic loading will quickly cause failure. Obviously you will return to using stock bolts in this application.

I think the limit of the amount of money you can get back from the Fastenal place is what you paid for the 3 bolts. Glad you weren't injured or worse!