Tak Collimation Scope

Does anyone know what I kind of grease I can use on the Takahashi collimation scope's o-rings? The problem I'm having is the end of the scope wants to separate from the body when my cassegrain is pointed towards the sky. This is the optimal position since the mirror is completely engaged with the mirror supports. It's really a wonderful collimation device but a very poor design because there is no stop to prevent the "eyepiece" from falling to the ground. I suspect removal of grease will make it worse because the grease has a certain amount of stickiness to it. I'm looking for a grease that won't migrate to the lens assembly at the rear of the collimator.

Thanks, Martin

Pink Floyd said it best.."Is there anybody out there"? The Tak forum is dead. Martin