Ford Repair: 2009 Explorer brake squeal, 9K miles, brake squeal, hat style

Question
The rr brake intermittently and randomly squeals while driving. Light pressure on the P brake will stop the noise. Returns again randomly. Dealer has had it 3 times, cleaned dust and lubed first time, adjusted P brake retraction/slack second and 3rd times. Dlr says "hat style" rotor/drum can't be turned, at least drum part. Any ideas?  

Answer
The dealer is correct...  I don't think the problem is coming from the parking brake.  Usually the squeals comes from the brake pads.  There is lube that can be applied on the back of the pads to stop the noise.  Not sure if this was done.  If this true, then check the caliper is in good working condiition...  Otherwise, look into changing the brake pads as they might be bad quality.  

Generally, the squealing noise does not impact car function but is not pleasent to drive with....

Sam Gorgey