Well, I don't think it's a proportioning valve anyway. It's on my 1970 Javelin. It had power drum brakes all around. I am putting bendix calipers, and the other disc parts from a 75 Hornet on the Javelin. Anyway I'm dismantling the entire brake system and cleaning and replacing things. So I pull all the brake lines off the "valve" (actually it looks like a safety switch only, the "piston" inside can only move toward the side of the failure to allow the spring loaded switch to become energized and illuminate the brake warning light. Now I know why it hasn't done that after a couple of master cylinder failures. The piston was cobbled up with debris and was stuck. Anyway as I was taking it apart and cleaning I noticed this yellowish looking stuff inside that appears to be the remnants of some sort of assembly lube. It was packed into the area towards the center of the two little piston pieces that have o-rings on them. What is this stuff and what should I reassemble this thing with? Maybe regular brake fluid would be OK for an assembly lube, anyone have any good ideas? Oh yeah almost forgot, one o-ring has two flat spots on it so I have to replace that, I will try the local Ace Hardware store, they usually carry a very good variety of o-rings, or ? if I can't find them there any other place you guys have found these tiny little buggers? They are about 3/8" od and about 1/16" thick, don't know the id, I'm afraid to remove them until I find a replacement. How many other brave souls have disassembled one of this with any success? I hope I'm successful................. Armand