Re-extending Collapsed Bumper Shocks

[jjeffries]

EDIT: Please see note below which explains why my suggested fix may result in a bumper shock that looks right but has lost its full protective capabilities. Apparently these shocks should be discarded once they've been compressed.


I recently bought an 87 924S which has been off the road for at least 12 years and had light nose damage. I pulled the front bumper blade and found the shock on that side had (done it's job and) collapsed. I pulled another one from a local wreck but it too was pushed in.

Last night I managed to re-extend both the one from my car and the other from the wreck. Here's how; so far they have maintained the length I set them to.





John

[944 Ecology]

Ingenious!

[9FF]

Just checking that you are aware that, even though you’ve extended them, once they have collapsed they are useless and won’t protect your car again if it has another shunt.

[jjeffries]

9FF, please explain. I'm not doubting you, but my assumption (happy to admit if I was wrong) was that when the shock was initially compressed, the oil within was forced from one area through a small orifice to another, and that in my application of steady force to re-extend it, I was merely pushing the oil back through the orifice in the opposite direction, to its original location. Is that incorrect? I certainly don't wish to be a purveyor of bad information. Thanks in advance, John

[9FF]

Originally Posted by jjeffries

9FF, please explain....

The hydraulic fluid in the bumper shocks is under gas pressure and the reason that they don’t just rebound back is that the gas has been exhausted due to the impact. Folk that have stupidly cut or drilled those shocks have had first hand experience that the fluid is not just under hydraulic pressure when it blasts out at them under extreme gas pressure. That is why they are a one time use item according to Porsche.

[jjeffries]

Much appreciated. I've added a cautionary note at the beginning of my original post.