I think I've finally found the culprit in the rear of my R53 that makes a thumping/clunking sound. It seems to be emanating mostly from the passenger-side of the fuel tank.

(After taking it to a muffler shop to check the Borla's clearance and me Dynamatting the vapor recovery canister.)

I think I'll hand it off to a mechanic with a lift. A floor jack isn't going to cut it.

Any words of wisdom?
Information seems a bit sparse.
Does the tank have to be removed to put isolating strips on the top or just lowered?

 

Fueller? Berris Fueller?

 

I see you have my twin, even with the Borla Exhaust, music to my ears....

Your thumping, do you have a stock suspension? I had thumping first on my passenger side, then on the drivers side, drove me nuts. Changed everything out, still thumped. I finally figured that is was the neoprene boots that fit under the top part of the strut, it rests on the strut rod and there is nothing that really keeps in in place. I took the strut off, removed the spring and pushed down on the boot, it slid all the way past where it was supposed to be seating. I went to the hardware store and got washers that were large enough to fit over the strut rod and seat, and small enough to fit inside the neoprene boot, it no longer pushed past its seat point. No more knocking around in the back. Hopefully you know what I am talking about, if not I will try and find some pictures of the neoprene boot. You may want to look into that before messing with your fuel tank.

 

If this is what I am thinking, there is a spacer (about 1" in length) that slips over the strut rod and keeps pressure on the upper plate once the nut is tightened. What is weird is that none of the Realoem templates show the spacer not the top rubber cam that sits below the nut/pan washer.

 

That spacer is not the part I'm talking about. It's the rear foam strut bump stop. It seats over the strut rod, when it no longer seats properly, it makes the thumping, clunking noise, at least that was my problem. If you turn it upside down and look inside you will see where it rests on the strut rod. It seems like a little extra pressure will make it ride down on the strut rod. I pushed a washer up in the hole that was big enough to fit over the strut rod and seat.

https://www.pelicanparts.com/catalog...SUSSHK_pg3.htm

Part #: 33-50-6-763-137-BOE

Maybe that is the problem you are having?

What's strange is, the part # references the R52, I have an R53 and the part that shows in the site is different, it seems like a shorter bump stop for the R53

This is correct part, Part #: 33-53-1-518-391-M26

 

I did have the original shocks and such replaced a year ago with Bilstein B4s with this kit:

 

I had noises coming from the tank and it was those clips on the straps. Have them check them out and make sure they are not rubbing or loose. 16136753087

http://www.realoem.com/bmw/enUS/show...diagId=16_0523

https://www.ecstuning.com/b-genuine-...136753087~oem/

 

There are three bolts that hold the suspension to the body, they can lossen up and at worst strip the body mounting threads, if they are loose, tighten them, or you will be doing some serious corrective work, to fix them!