Originally Posted by
Andrew R Stewart
The goal is to remove the old gummy lube, not just dilute it. Solvents and penetrating oils are poor lube, although they usually work well for the dissolving the old they are poor lubes and really will want a follow up with a true lube (which WD40 isn't). Andy
I would disagree. The goal isn’t to remove the old lube because it is very difficult to put lubricant back into the shifter without disassembly which Shimano has made very difficult. The goal is to “refresh” the old grease which was likely a soap based lubricant rather than the newer synthetic lubricants that don’t break down as easily. Newer shifters don’t suffer from the “gummy grease” problem at nearly the rate as the older shifters did probably because of a change in the grease being used.
Any spray lubricant is going to contain solvents. That’s the only way that the lubricant can be “sprayed” into place. WD-40 really isn’t any different from any other spray lubricant you care to name. The factory lubricant on shifters is a paste or semisolid lubricant that was physically placed on the part. Any spray lubricant…including WD-40…is going to be inferior to that kind of lubrication because the solvent is used to penetrate and the hope is that enough of the lubricant will be left behind.
WD-40 does have an advantage over just straight up spray degreasers in that they don’t leave
any lubricant behind. At least some lubrication is left with WD-40 (or PB Blaster)