I rebuilt my early girling brake booster from a BT7, but it still did not work. I removed it again and have had in sleeved an I am ready to reassemble. The first time I rebuilt I had a kit from MOSS Motors which had a grease in it to grease the leather on the vacuum cylinder. All my original parts of the first rebuild are fine, I just don't have any grease anymore. What was that grease or what is recommended. Is there any way to check this thing before it is back on the car. Hard to take on and off.