If your 928 is earlier than VIN 92ES860404, use a small magnet to test the lower ball joint supports. Another indication is that the steel supports have a figure-eight shape, while the aluminum supports have an oval outline.
If you have aluminum ball joint supports, I strongly urge you to change them at the earliest opprotunity.
You will need two each 928.341.049.12 ball joint supports; four each 928.341.466.00 adjusting eccentrics; one 928.341.091.05 left bracket; and one 928.341.092.05 right bracket.
While you are in there, you might consider replacing the rubber boots for the upper ball joints. The upper ball joints are not replaceable - you have to replace the entire upper a-frame ($$$). New boots will help prevent dirt from entering the upper joints.
Wally Plumley
928 Specialists
928 International has a source for rebuilding upper A-Frames. While you are
replacing things you might want to consider sending them your upper A-Frames
and have new ball joints pressed into them. Just an alternate to buying new
parts.
Jay K.