pics are waaaaay to big

fix it please

That failure was definitely caused by a fatigue crack that began at a small defect on the surface of the metal. The crack slowly ate it's way through the rod. Each of thousands of vibrations caused the crack to deepen. If you look at the face of the failure under a microscope you will see thousands of arching lines radiating out from a single point at the edge of the failure. This caused a smooth surface across a portion of the face of the failure. The metal at the center of the rod tore because the rod became too weak to support the load and the metal there is rough and jagged.

Earl
(former metallurgical engineering technician)

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Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra

Its a somewhat common failure for the 124 chassis from what I've seen in my area. If that joint starts making noise replace it asap.

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1980 500SE/AMG Euro
1981 500SEL Euro
1982 380SEL
1983 300TD
1983 500SEC/AMG Euro
1984 500SEC
1984 300TD Euro
1986 190E 2.3-16
1986 190E 2.3
1987 300D
1997 C36 AMG
2003 C320T 4matic

past: 1969 280SE 4.5 | 1978 240D | 1978 300D | 1981 300SD | 1981 300SD | 1982 300CD | 1983 300CD | 1983 300SD | 1983 380SEC | 1984 300D | 1984 300D | 1984 300TD | 1984 500SEL | 1984 300SD | 1985 300D | 1986 300E | 1986 560SEL | 1986 560SEL/Carat | 1987 560SEC | 1991 300D 2.5 | 2006 R350

Here is a photo of a 1 year old ball joint pin failure which luckily occurred during a parking maneuver. The rubber boot has been removed and the grease flushed out to try to determine the cause.

No rust, boot intact, well greased, no pre-failure noise.

The cause: a crack of unknown origin that worked its way across the pin until it let go. The face of the fracture is slightly "peened" from pre-failure movement indicating that the failure process began ?? hours/days before the actual parting.

Ball joint source: eBay. Lesson learned.

Both sides replaced with Merc factory ball joints.

Regards,
bobf.

Attached Thumbnails

 

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2.3-16:ROTREXsupercharger;water/air intercooler;Megasquirt EFI/EDIS/COP;2.5-16cams&exh manifold;3"exh;YellowSpeedRacing adjustable suspension kit all round;28mm ARB front,22mm rear;C32 brakesfront,AmgCl55alloyrear;500e servo/mstr cyl;RDMTEKstrut towers;Speedtek camberarms rear;nylonsubframe bushes;Poly-u bushes front&rear,SPEC lightened pressure plate;manual locking 3.07ASD diff;short shift gear change;215 front,235X40X17 rear,EVO8.25 rims

If you look at the face of the failure using a strong magnifying glass or place it under a microscope you will see the origin (beginning) of the crack an in turn you will see the defect in the steel that caused the metal to fatigue at that point and begin to crack.

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Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra

Try to get a picture like this.

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Beautiful picture. Is that a threaded bolt? Can you see the origin? Imagine dropping a pebble at the very edge of a pond. The resulting circular pattern of waves is what the origin will look like only very minute partial circles.

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Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra

As you used to do, I do this stuff for a living. The picture is from a wheel bolt that snapped from a single event, no fatigue. This picture was before we improved our camera equipment. I couldn't find a good example of fatigue from my portfolio on the quick.

Aaahhh OK. I could not figure out the type of failure because of the multiple planes and the out of focus portions of the rest of them. I figured the origin must be on one of the unfocused portions of the failure.

It would be neat if you could find an origin to show to the forum. Also you might mention that viewers should click on the small picture.

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Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra

How can one tell if they need their LCA bushings replaced? I need to replace my Outer tie rods and Shock absorbers in my 1997 E300d. The shop said these were bad but everthing else looked okay. I thought I would go out and purchase the best parts and replace them myself and then go back and have them to a four wheel alighnment on their new Hunter machine. THey were going to charge $820 to do all this plus alignment but was not sure what brand parts they installed. I could get Bilstein shocks for about $270 for all four. Im not sure what brand tie rod I should purchase. Any suggestions? Thanks

Nasty, good job it didn't happen at speed eh.

Shame there isn't a boot over the joint to protect it better...

cheers

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cheers!!

this happened to me in a public parking lot on the 3rd level.i was pulling out backwards with a hard turn to avoid the line of cars behind me.a loud bang and the left front wheel turned inward.i was able to get the car back into the parking.but it soon turned into a 2 hr ordeal getting the car out because the overhead clearance would not allow the tow truck in.we had to put the car on a shop jack and drive it.first up one level due to the design of the parking garage.and then down a steep spiral down ramp to the street.$200 in towing chgs later i had my 87 300tdt home.the ball had completely pulled out of the joint.after a review of the service records i received from the PO i discovered that 1 ball joint had been replaced several years earlier.i just shook my head.what whats that mechanic thinking at the time?

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michael cole 1980 300SD gone now but not forgotten,87tdt,90 300te 4matic 95 e320 wagon

as a reminder of what can happen.
.

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ASE Master Mechanic
asemastermechanic@juno.com

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