spray with Silicone spray not WD40 as that dries outthere is a tiny piece of glass in the rubber somewhere by the sound of itget the glass out and stick a small screw driver in and the rubber and slide it around till you pick it out
WD40 and GT85 are both water dispersants - so as above, don't spray seals with it!On mine, the squeal was the metal guides, I coated them with copper slip, then noise gone.