My 1985 wagon has the M8 triple square head on the fasteners. If you use an allen wrench you will strip it out. Ask me how I know this.

1. Lift the hatch and support.
2. Remove the clips and pins that hold the strut st the hatch.
3. Remove the rear panel at the headliner.
4. Locate the bolt that holds the strut in and see if it is hex or triple square.
5. Use the appropriate tool to remove the bolt.
6. Assemble with new strut in reverse order.

I bought mine off of a place in Miami and they sent the wrong ones the first time, but got it right the second time.

__________________
Doug

1987 300TD x 3
2005 E320CDI