Faucet Diverter Valve Replacement how-to DIY tips

I once changed a faucet diverter valve in a shower/tub.  It was not too difficult.  15 years or so later, it started leaking. 

I think I forgot to apply plumbers' silicone grease to the O-rings.

I bought a cheapo replenishment kit, and sprayed copious quantities of silicone lubricant spray, repeatedly, while diligently trying to pull out the diverter valve assembly without laying out for a $100 specialized tool for the job.

I could not pull it out, but it began to budge sideways a bit as I tried to gently use the cheapo plastic thingy in the cheapo replenishment kit to break some bonds.

Cor'n'Blimey! Lo and behold!  The copious quantities of silicone lubricant spray appear to have rejuvenated the O-rings and/or dislodged some grit.  No more leak.  That's all I can say about it for now.

Maybe worth a shot.