When I took one of my chargers apart I found lots of metal stuck in the main shaft oil way, it was the left overs of an old Oil Seal spring, it had broken up and I reckon once all was out (it took me ages to fish it all out!) I had enough to build the pressure up on one side of the charger seals.
this was a charger I bought second hand so I never ran it like this but I dare say it couldn't have been efficient running like this.
So if you have the charger apart check the oil ways inside the main shaft!