1900 rear caliper refurb

[Rallyace 3]

I’m in the process of rebuilding some rear calipers. Although I've put 1900 in the topic description, I believe that the axle and therefore the calipers are from a 306, as the piston diameter is 32mm, rather than 30mm.

The handbrake mechanism on both was tight (seized) and I had to disassemble completely to get it working again. I’ve done one and  everything seems good with obvious and smooth  movement of the piston when moving the handbrake lever on the caliper. 
My question is about the material that was packed around the mechanism. The working parts under the rubber cover. It’s almost like a moulded rubber/plastic which I’ve scraped off with a screwdriver. On the one that I’ve already reassembled I’ve added a generous amount of black grease before refitting the rubber cover. 
From those that have done this before, does this seem right? What’s the original material?

[welshpug 1,650]

it would have been some kind of grease, you don't need loads on there, decades old heat cycled grease does make some weird consistency substances!

 

axle wouldn't have been from a 306 unless some substantial shell mods were done and it has dimma or maxi rear arches..

[Rallyace 3]

Thanks. It’s certainly a strange consistency.