I'm having water flow problems with my Rohl faucet in the kitchen. Have narrowed down to diverter valve problem - the aerator is clean, and the cartridge appears to be working correctly. I can obtain the replacement part from Rohl but don't know how to remove the old one. It's pressed into the base really well, and from photos of the replacement part it appears to have rubber o-rings that will hold it in place pretty well. Is there a special tool required to remove it?

Plumbing - Rohl - A3608/11LMAPC Single Lever Country Kitchen Faucet with...