Whiteline snapped rear upper arm

[Trex]

Whiteline quick clip suspension arms

These are the next thing to hit the scene. I currently have the first set in the country and let me tell you, these things are incredible! 

 

But seriously, what do you think happened? has anyone seen this before?

 

 

[Duncan]

Well, I'm no mechanic, but I think it snapped.

Must have been an exciting moment.....

[Trex]

All crossed up at 80kmph  The cornering grip of the stagea was too much for the arm.

[niZmO_Man]

Via the Subaru forums, it seems Whiteline aren't the best at making "links".

[MrStabby]

Interesting that 40% is smooth and the other 60% is rough. Are there a bunch of parallel lines on the smooth bit?

 

[Trex]

Whiteline has come to the party and sent me a replacement rod today. No more stance life.

The smooth bit is completely smooth. It starts at the very first thread from the centre nut. Either a machining defect or stress over a long period of time. Whiteline hasn't given me an answer yet though.

[Dose Pipe Sutututu]

Who needs air bags when you've got link snaps!

Instant camber for the EOMM or car park meets lol.

Lucky no one was hurt or any injuries were had on the car.

Funny how a premium product can snap like that.

[warps]

That's fatigue failure. Started at the thread.

 Are they rolled or cut threads?  Looks like it's been loaded in bending.  If the bush in the pivot was binding it might be enough to cause the fatigue to start.  Bolts hate bending stress. 

[Trex]

I couldn't tell you. They look cut to me.

I was thibkjust by maybe at full droop and back to compression may be the cause. Is that what your saying?

They will have to be routinely checked now.

[niZmO_Man]

Maybe design it beefier next time? Or some some super awesome Oxcart titanium alloy

[Missileman]

could also get the new ones cryoed.

[Smally514]

It was a good two hours on the side of a closed off road quickest cotter run I've ever done

[Trex]

38 minutes ago, Smally514 said:

It was a good two hours on the side of a closed off road quickest cotter run I've ever done

I didn't get till around 8 haha

Again, thanks for staying with me the whole time  

[Smally514]

No dramas man couldn't leave you stranded out there by yourself that's just a dog act haha. Besides talking about cars took away from the temperature drop and waiting time haha.

[warps]

19 hours ago, Trex said:

I couldn't tell you. They look cut to me.

I was thibkjust by maybe at full droop and back to compression may be the cause. Is that what your saying?

They will have to be routinely checked now.

Is the smooth part (called beach marks,  or crack propagation zone) towards the top / bottom of the rod when in normal position, or towards the side  (i.e. is the line at the edge between the smooth and rough parts horizontal or vertical with the arm in position)?

If the beach mark area is towards the top / bottom then it sounds like the bush is binding. Poly bushes are notorious for being sticky  (hard to rotate around the pivot ). That's bad in a suspension system for a lot of reasons, one of which being the bending loads they can place on the arms.

As you suggest,  it could be bottoming out,  which could be overloading the arm too.

When you refit the arm, make sure that the arm is free to pivot through the full range of motion before you refit Springs and the rest of the suspension.

[Trex]

Yep the smooth section is dead vertical on the bottom.

I did notice the bush was captive in the mount. You could pull the arm down and it would fling back into place horizontally how it was installed. In the back of my mind I thought the sleeve should protrude and be the main contact but thought whiteline would know more than myself.
I will have to grease these sections of the bush and get some lock nuts.

I will have to take a video and send it to them.

They suggested I need their traction rods to help aid in the stress lol. I can't see how this will help at all when the new traction rod will be the exact same length and stock.

[Trex]

Thanks warps.

[zoomzoom]

When installing poly bushings in the rear A arms, I did shorten the split bushings so that the arm would be able to pivot up and down without being able to move back and forth too much. Superpro ones were far too tight (ie too long).

 

[bigmikespec]

What country are you in? I have had these on my car for 5 years, they are not new.

[Duncan]

Assuming they mean adjustable traction arms, they definitely can make a difference to both binding and bump steer...when you change the length of the main upper arm but not the front/traction arm you change the geometry.