Often, Operations personnel are reluctant to release equipment to Maintenance because they have been "burned" by broken promises in the past. That's understandable; in a reactive environment, it's difficult to make accurate estimates for repair duration because you usually don't know what you're going to find until you get into the equipment. Nor do you know what parts are going to be needed or whether you have them in stock.
Creating a schedule for all the work you intend to do next week literally forces you to have forethought about the jobs you intend to do, including how long they will take. Even if you're not formally planning, these estimates will likely average out to +/-30% accuracy when compared to actual performance. Planning, of course, will improve this accuracy and cut the variability in half. (Kister, Timothy C. and Hawkins, Bruce, 2006, Maintenance Planning and Scheduling Handbook - Streamline Your Organization for a Lean Environment, Elsevier, Burlington MA, page 243.)
When you sit down with Operations to create the schedule, two things will likely happen: they will realize that you're attempting to schedule your necessary work at a time most convenient to them, and they will gain an appreciation for all of the work you have to do in the week. They will no longer make the assumption that your craft technicians are sitting back in the shop, waiting for something to break. The schedule becomes a "contract" between the two parties - Maintenance agrees to have the resources (labor and materials) available to perform the work, and Operations agrees to have the equipment available at the appointed time.
Tip provided by Management Resources Group, Inc.