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Shock shaft fell out... pics... need opinions

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My buddy was racing over the weekend and wrecked pretty bad.

He did not completely remember what happened but when we got his bike back to the pits it was obvious.

The shaft was falling out of the shock. His bike turned into a pogo stick and it tossed him violently and without warning.

He had the shaft replaced recently and to me it looks like the nut backed out then what threads were left got pulled out.

The threads on the shaft seem to be fine. We are not goingt o take the shock apart because he is going to send it back to the company that did the work.

Have you guys ever seen this?

Any way to avoid it in the future?

DSC00894.jpg

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Whoever did the work on the shock, may not have used a high temp thread sealant or didn't clean ALL of the shock fluid off before applying the thread sealant.

Ride on

Brewster

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Or is it possible it leaked, rebound went really fast and he rode it some more and the force pulled the rod out?

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Have you guys ever seen this?

Any way to avoid it in the future?

i've seen such things several times - usually on forks after 'home made' revalving.

reason for this and how to avoid it, see brewster's comment

i always degrease with break cleaner and use green Loctite 2701 as thread sealant

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OK... makes sense...

The work was actually done by one of the bigger suspension shops.

Not that anyone is asking but I do not want to say who did the work til they have a chance to rectify the situation.

I am asking because I have recently started to service my own shocks and NEVER want this to happen on a shock I worked on.

I really dont think it was leaking before he went out there... but can't be 100% certain.

He did hear a click coming from the rear of his bike but we just thought it was the upper shocking bushing/bearing.

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Im thinking then maybe the shock was topping out and that was the clicking noise? too little sag maybe, all just guesses, its probably as others have said and a bad build.

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One comment however is even if they used some bad threadlock it should not have come loose it tightened correctly.

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Someone on another board pointed out that if the bike cartwheeled and landed on the top of the rear wheel.... the shaft could have been pulled through the nut....

Hadn't thought of that... but it is possible.

I did not see the crash (just heard that panic rev... he is one of the only 2-strokes left out there)... by the time I round the corner he was rolling off the track and the bike was "ghost" riding the other direction...

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One comment however is even if they used some bad threadlock it should not have come loose it tightened correctly.

Sure it can, vibration can loosen any properly torqued bolt or nut. This is one reason the factorys go to such lengths to peen over the nut. Proper use of thread lock is a must whenever a shock or fork has been revlaved.

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This issue can also happen from over tightening the nut. The threads get "pulled" a bit, and eventually fail.

When I was in the 82nd Airborne Division jumping out of Blackhawks and Huey helos, the mechanics always referred to the large nut holding the rotor in place as the "Jesus Nut". I always think of that when properly tightening the shock shaft nut!!

Take Care, John

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