I have built the shocks on my TC3 and TC4 plenty of times but this is baffling me. I have had two leaking shocks recently. It appears the VCS bobbin has lost its holding strength and no longer wants to stay "seated" in the bottom of the shock body. This allows the o-rings to uncompress and move up with the VCS bobbin which allows oil out. Do these things wear out from time to time? This is happening on my TC4. I had my TC3 A LOT longer than I've had my TC4 and I never once had this problem with this car. Thanks for letting me post this here. If I remember correctly the internals of the shocks between the 4 and 3 are identical. Any idea besides buying new VCS bobbins?