Trek used a wedge type eccentric for its tandems and it often times takes a little brute force to get the things apart.

The textbook service procedure is to back out the eccentric bolt to expose the head and then to tap it with a mallet to release the tension between the eccentric and the wedge. However, the most often cited removal methods from those who've owned the older Trek's include:

1. Remove the eccentric bolt and temporarily replace it with another, longer bolt that has the same thread pitch and diameter and thread it as deeply as possible into the wedge before hitting the bolt head with a hammer to drive out the wedge. Note: the tandem frame must be braced by a helper otherwise the bike will move with each hit, lessening the driving force.

2. The less brutal method involves placing a lever between the bolt head and the crank arm and using the crank arm's rotation to drive the lever against the bolt head and forcing it in. You only need to have about 1/2 of the eccentric bolt head extending from the eccentric for this method to work. Cresent wrenches (aka, spanners or adjustable wrenches), hammer heads, and other solid objects have been listed as "levers" in previous descriptions that we've come across.

As for those "rotator holes", you can usually rotate the eccentric with your fingers once they're loose. However, if you need to have added leverage you'll want to pick up a Park SP-1 pin spanner (Green Handle).