Auto Air Conditioning & Heater Repair: 2003 Suburban A/C Pressure, condenser dryer, power steering pump

Question
I was having trouble with the A/C system on my wife's suburban last fall.  The idler pulley started "chattering" really bad.  Not from a bearing going bad, but from too much torque required to turn the compressor, so the belt would flex the pulley and then jerk back rapidly.  It was really loud and I was afraid if would throw the belt and she would be without air.  I first replaced the idler pulley/tensioner, and belt - twice.  That did not fix the problem.  I read online and found that symptom on those model suburbans typically was from a failing compressor.  So I took my compressor off and took it to a well respected local business and they rebuilt it with all new seals, and components.  Then I re-installed the compressor with a new condenser, dryer, and new orifice tube.  Blew out all of the lines, pulled a vacuum, and recharged the system.  It blows really cold air, but the chatter never went away.  I re-checked the pressures today.  It was roughly 100 ambient temp and the high side was around 225 psi and the low side was around 45 psi.  

Is this the correct high and low side pressures for that system?  I can't find any exact specs.  Any other suggestions to stop the idler chatter?

Answer
Hi Jonathan

Your pressures are a little low for that ambient temp.  You should bring the pressure up to about 50-55 psi on the low.  but before you bring it up and put more force on the compressor.  Check all components on the  drive belt system.  Especially your power steering pump bracket.  Some time the brackets are either cracked or loose and your compressor will put that extra strain on the system.  Good luck let me know.