I was looking for a quick way to stop the rattle on my 4 point Detachable Backrest & Luggage Rack. I have seen a bunch of different post scattered in different areas of the forums. So I posted here for more people to find in a more generic search area.
The main cause of the rattle is usually not a tight enough fit of the Plastic Inserts of the docks themselves that make contact with the metal of the Rest/Rack.
Some are sized that way from the factory and others may have worn flat spots over time.
Mine has the flat spots that you can almost see but can for sure feel with your fingers. I had seen that many folks tried a bunch of fixes with no real inexpensive fix besides wrapping electrical tape around the inside plastic dock inserts to fill the gap a bit.
This seams too temporary and tape adhesive tends to get soft from heat and melt to sticky grime. I do not want that touching my chrome parts even in a spot you cannot really see when installed.

So here is what I found:
I did a few experiments and found a nice fix that is more clean and durable.

Rubber O-Rings...

Go to Home Depot in the plumbing/faucet parts area and you will find a crap load of O-Rings.
They stretch around the docks and fit just right around the inserts.
I tried different spots and different amounts of rings on each dock too many and it will not latch right or could be so tight that it is way too hard to unlock and remove it again.
I ride a 1999 Fatboy & it worked best with just one O-Ring on each Dock Insert. I stretch one onto each dock and slide/roll them to the inside edge of the dock (the edge closet to the fender).
The Rest/ Rack system now fits snug, quiet, latches easy and tight with no trouble taking it off and on repeatedly.

Oh, the O-Rings that worked best for me are "Danco" #40 O-Ring
sized 3/4"O.D. x 5/8" I.D. x 1/16"
They come in a little clear snap box with 10 in a box for less than $3.oo.
The part number on the box is 96754.
Now that’s a cheap fix. Done deal for 3 bucks.
I bought 2 boxes for the hell of it, if a ring breaks, or if a friend needs some.

Hope this helps some of ya... Ride On.

 

Thanks for the post!! Now I'm going to head over to homedepo and pick up a box of orings for my bike!

 

Sounds like a good idea - thanks.