A Q-400 Captain raises concerns about the lack of any master caution or red light alerting flight crews about the loss of 'normal' brakes hydraulic system pressure when the #1 hydraulic system isolation valve light illuminates on the overhead panel. Captain also noted the emergency checklist did not address an 'on-ground' condition to 'not' taxi an aircraft with an isolation light illuminated.

Narrative

We were scheduled to depart in first aircraft and during preflight found it had a loose boot patch. [We] called for Maintenance [and] switched into second aircraft which just had been cleared by Maintenance [after] a hydraulic problem. Loaded passengers and pushed back; starting engine one during the push. At end of push found that the #1 hydraulic isolation valve and inboard spoiler caution lights were illuminated. [We] checked the emergency checklist for any solutions and called Dispatch and Maintenance Control while parked on the ramp. Maintenance Control had no solutions and said to return to gate. Taxied back to the gate [and] when slowing to enter the parking spot I discovered that I had no brakes. [I] immediately called for the First Officer to apply brakes while I also pulled power back to max reverse and applied the parking brake. The aircraft came to an abrupt stop; not hitting anything.After shutdown we reviewed the emergency checklist and realized that we had read; and then in the confusion; missed the fact that the brakes will not be operative; this was my error. To improve the clarity of the checklist so it is not as easily missed; I would strongly suggest that the emergency checklist start out with an 'in-flight' or 'on-ground' question that would then lead to the proper actions required. On-ground should state clearly to 'not taxi' and Maintenance Control should have this issue flagged so they do not suggest moving the aircraft. Submitted a Captain's irregularity report.I was informed later (unofficially) that Maintenance is missing a part of their procedures for resetting the #1 hydraulic system isolation valve. This would be needed for the type of hydraulic event that happened prior to us getting in the aircraft. This led to an un-airworthy aircraft being given to me. Due to the workload of calling Dispatch; Station Operations; and Maintenance Control after discovering the problem; the fact that the emergency checklist did state that brakes would be lost was forgotten when Maintenance Control said to taxi back in. The checklist does read as if it was meant for 'in-flight' use and has no 'on-ground' section to start with. There are no aircraft caution lights for the total loss of brake pressure.