Girling makes a grease that should work. It is used for brake seals and rubber components. Try a British auto parts store or some place like Pegasus who sells formula ford type supplies. http://pegasusautoracing.com/
Their part number is #3306 Brake Assembly Lube.
A forum community dedicated to 1st generation Chevy Camaros owners and enthusiasts. Come join the discussion about performance, builds, restoration, modifications, classifieds, troubleshooting, reviews, and more!