My A8 has quite a noisy Y-azis. The 8mm holes in the perspex front and back are fractionally over-sized (if not, assembly would be tricky).
Here is a set of clamps which can replace the tear-drop perspex plates which retain these rods. Use an M3x12 cap-screw to tighten them, and the original M3 bolts to secure them. No need to over-tighten.
Although I didn't observe any significant reduction in the movement of the bed (using a dial gauge, about 0.2mm) this movement is now all from flexig of the rods, not movement. So, it's quieter and maybe smoother at higher speeds.
STL for each corner, or the whole set. There is a mounting for the Y-axis limit switch, and a version of rear-right without this too.
Also added a Z-axis version, which is quite a bit longer.
I made the main hole a little over-sized, for easier fitting, but this shouldn't matter. Use a bit less than 100% infill to make sure it's flexible.
24 May 2017
Updated to add clearance for wing nuts. It is still possible that the wing nuts catch on this clip, so its better to replace them with a normal nut
Depending on how you have the Y axis arranged, and the length of your rods, you might loose a couple of mm of Y travel. With this mod, you can increase the Y offset front/back slightly to compensate.