Mine were definitely steel. Just went and grabbed them out of the waste/spare parts box. Come to think of it, Frank, my bolts were questionable. I checked them with a thread guage and they appeared to be stretched ever so slghtly. I went with a new filter adapter, hoses, banjos, and gasket-orings at all joints. Also had to RTV the (what looked to be) aluminum washer for the bypass valve on the bottom. That, and cranking the snot out of it, was the only way I could get it to stop peeing. Hope that helps <img src="/forums/images/graemlins/cheers.gif" alt="" />