W124 pulleys loose? Get new or retighten and how

[bru023]

My air injection pump pulley is very loose. Do I need it. I tried tightening it but it just spins it has a big 17 millimeter nut. Is there a trick to this or special tools I have the fan holding tool


Also the main pulley the one with no grooves or teeth in it when I spin it it hits some metal and gets stuck once in awhile.

Any ideas would be helpful any help thank you