Fork stays compressed when bike is ridden - can it be fixed?

I_Like_Snow

This is a 2000 Cannondale F700. The fork is a Headshok Fatty DL with 70mm of “air-sprung/oil-damped” travel.
The owner has stored the bike hanging upside down for over a year and the bike has seen little use over the past few years. The owner has said that some sort of liquid has dripped out of the fork headset from being hung upside down. I assume that this is the oil that is mentioned in the description of the fork on the Cannondale website.
Overall the bike looks like it is in great condition. It shifts great and otherwise but the front fork has an issue. The fork can still be locked out so that there is no give whatsoever, but when the fork is not locked out it will compress completely down from my forward weight and consequently eliminate any dampening ability that it should have. This occurs despite me not leaning forward on the handlebars or otherwise – the shock just completely compresses down once I get on the bike and begin pedaling.
I like the Headshok and would like to avoid the cost of replacing it but I am not sure if this is possible. I am hoping that this is something that can be repaired.
Has anyone here experienced a similar problem? How did you fix it?
I plan on calling around to some local shops to find out what they think of the issue but I was hoping that someone here may have some helpful information as well.
Thanks to any and all related information.

schwagger

Happens often ,send it back to c'dale for a rebuild should be less than $100-,easy fix.

backpacker134

have you tried the www.spokesexperts.com