I've noticed coolant is getting into the hydraulic unit from somewhere. Has anyone had this problem. Possibly a seal on the chuck?

If I remember correctly, that's exactly what it is, although what I can't remember is if MAZAK has a return tube for excess hydraulic fluid that could also be getting contaminated, but I don't think so. Most likely an o-ring in the spindle/chuck.

The two places that coolant and hyd are close to each other are in/on the turret, and the power chuck accuator. 99% of the time it is just a p-10 o-ring on the cooland block on the turret. Very easy to fix on some turrets a little harder on others. Depends on if the coolant piston is behind the turret (remove turret to fix) or mounted next to the turret.

Justin Terry

yup........
also some machiones on top the hyd tank is a tube from the pump this could be dislodged letting stuff on top the tank get in
but my first thought would be the coolant block although
what mine usualy does is drain the hyd oil into the coolant not visa-versa