ire32

2009 CL550. Power steering has become heavy. This occurred after serpentine belt snapped and was replaced along with two tensioners. Steering was initially on and off heavy and the shop told me the PS cap was loose so they added fluid and tightened the cap. When became constant heavy steering I checked the fluid level and they had over filled it to the top. I removed fluid back to proper level but steering is still heavy. Any recommendations will be appreciated.