I'm sure that my empeg used to push itself out of the sled when the handle was lifted when it was installed in my old car (but it was about a year ago so I can't really remember)

Now it's installed in my new car, it doesn't do this. Any idea why? I've had a look and tried to figure ot the mechanism but i'm stumped.

EDIT: I should have used the FAQ, Luke

Why is my Mark 2 hard to pull out of the sled?
(Entry last updated on March 31st, 2003)
There are several reasons that your Mark 2/Rio Car might be tough to pull out of the sled, but the most common problem is loose docking connector screws.

Check and tighten the two screws that hold the docking connector to the back of the player. They should be tight. Note that the docking connector is deliberately designed to wiggle even if the screws are tight (see here for details).

Some users have reported that the screws worked loose on their players, causing the docking connector to come completely disconnected from the player. This made it difficult to pull the player from the car docking sled, and also caused the wiring harnesses to pull loose from inside the player. If this happens, hopefully the only damage was the internal connectors being pulled from the motherboard, and they simply need to be plugged back in. Contact support if you need help with this.

Other possible causes for difficulty would be loose screws on the sides of the case, a sled that's bent or installed crooked, or the sled's keeper tabs bending inward and interfering with the player's casing.

No, the handle is just a latch to hold the unit in. There is nothing in the sled, or the handle latch, that would make the unit pop out if you lift the handle. You have to pull it out yourself.

Hmm, I'm sure that as the handle is lifted it pushes on the edges of the sled and eases it out slightly?

Nope, it's just a latch that hooks into the sled to stop the unit popping out. There is a spring to make sure the handle returns to the locked position, but that's it.

I must have dreamt it then!

No, you didn't dream it. My Empeg does this too.
It seems the top edges of the handle (the part where it hinges onto the Empeg) are square in form other than round. Because of this, when the handle is pulled forward, these top edges push the Empeg 1-2mm out of the sled. Usually just far enough for the wire loom connector on the back of the sled to let go of the Empeg.

I don' t know if it was inteded this way or not, but it works quite well. Because of this I never have to put any brute force on it and the Empeg just slides right out.

Phew! I thought I was going mad!

Now all I've got to do is figure out why it isn't doing it any more

Probably loose screws on the handle, or slight variations in the mounting position, or maybe the screws holding the display assembly to the player casing are loose and/or the positioning of the various bits is slightly shifted. Various bits that connect the player to the sled (docking connector, guide bumps) could be working tighter than before. Sled frame could have been bent slightly to cause this. Also, the squarish bits on the back of the handle could simply be wearing down.

Rob is right, the player was never intended to do that, and it's something that doesn't happen to every player. On my player, I get a slight rub-marks at the friction points, but not an actual ejection motion.