HELP - Air Cylinder is knocking -

Help - I've been trying to figure this out for like weeks now. My rear passenger side air cylinder is knocking on the littlest bumps. It's pretty loud too. I've tightened all the bolts, and re-oiled the air cylinder just today, and nothing change, it actually got louder. I only have one more idea. Supposedly there is supposed to be a bushing on top and on the bottom of the top two bolts that go through the frame - I've only got them on the bottom. I'm going to get some other ones for the top, so I have all 4 bushings, I hope that fixes it, but if anybody that has air cylinders has seen this problem, let me know please - going on long trip this next week and I would like to not have to hear that knocking noise the whole 1300 miles.

Thanks

On normal struts there is a nut that you tighten down on the rod of the sturt. Look inside the car at where the sturt comes through the body and see if the nut on the strut rod it tight.

Air cylinders don't have that - they only have the 2 bolts that mount to the frame - the air line goes right through the center where that other bolt would be.