TwistedMinis
+1y
He is exactly right. Its is called a LSPV (load sensing proportioning valve). Personally, I prefer to replace them with a proportioning valve, otherwise you could lock up your rear brakes on hard braking, or in wet conditions. I used an adjustable Wilwood PV, but you can also get a factory valve that is meant for disc/drum applications off of a pre-84 2WD truck. They are located right below the master cylinder.