C219 W219 W211 Arnott Strut Top Mount Bolts Sheared - Not Good

[DanB]

Hi All,

I was having a go on the car again today and whilst I was cleaning in the engine bay I found the O/S top mount bolts for the front suspension strut have sheared off completely. I'm totally shocked (no pun) and have never seen this before.

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The strut is a pretty new Arnott item (not sure of the exact age of the strut but it looks like its less than 2 years old).

Apparently, according to Arnott, I need a new strut.

I think almost anything is serviceable so I hope to be able to remove the strut, disassemble the top mount, drill out the bolts, reinstall new ones but I'm finding it near impossible to find pictures of the struts disassembled, exploded diagrams of the struts etc. Arnott are not very helpful (I'm on it today) or forthcoming with information.

Are these items serviceable? Has anyone ever done this? Can I replace the top mount bolts? I thinks so because the bolts has a torx fitment similar to the strut piston (to hold it steady).

If anyone has any info or advice it would be much appreciated.

Cheers

Dan

 

[alexanderfoti]

I would say they must be servicable to some extent as somebody at Arnott must have put them together in the first place!

I would be inclined to do as you mention and take one apart. It looks like somebody over tightened them in the past. They do not take much load.

 

[DanB]

I think your right as to the reason they have sheared. Why some mechanics use impact guns on everything and ignore correct torque specs is beyond me.

They must be serviceable to an extent it's just whether I can get to the top mount studs as they look like they are part of a sealed unit.

I'm going to have a look over the weekend.

 

[alexanderfoti]

Is the snapped stud plastic or metal?

If metal, you can drill out the remaining bit, tap the hole and insert a stud with threadlocker. Should work fine

 

[DanB]

The studs are metal and have a hex fitting so they must be removable.

I really hope I can drill them out, and insert a new stud with thread locker. Fingers crossed Alex

 

[LostKiwi]

This may or may not help:

 

[DanB]

Thanks LostKiwi, that helps a lot.

I have also done some digging and it turns out the strut is a brand new Arnott strut. Not a remanufactured one. This makes a big difference.

The original OE strut has a steel case top mount with captive studs as show in LostKiwis find. It looks like a sealed unit that would be impossible to take apart and reassemble perfectly. Arnott take these "cores" and remanufacture them. Like this - Notice the top mount and studs - Steel case with captive studs

https://www.arnotteurope.com/produc...ercedes-benz-cls-class-w219-e-class-w211.html

They also make brand new one that differ from the OE / Reman OE in that they have a top mount CNC machined out of Aluminium. These type have a hex head in the stud - because a captive steel stud would damage the Aluminium? Therefore the hex head is to hold steady because the studs could well be removed when tightening to torque? I hope so.

https://www.arnotteurope.com/produc...trut-mercedes-e-classw211-cls-class-w219.html

Either way, the top mounts would be impossible for a diy mechanic to take apart and put back together. I just hope they are studs I can remove.