I cannot remember what it is that one does to that brake proportioning valve that is below the mst cyl to get things reset so the darn light goes off.
Can anyone refresh my memory?

Thanks

 

I don't think there is a reset. Inside the prop valve is a trapped piston. When either front or rear pressure drops, piston goes all the way front or rear, contacts complete a circuit, light comes on.

Happened to me on my 71. Turned out to be a bad wheel cylinder.

Could also be e brake circuit causing light to come on.

 

Well, I know there is a way to reset/reposition that plunger. I have done it, but that was SO long ago............

 

Hmmmmmmmmmm.............. I thought the plunger was lightly spring loaded so it would reset itself once the problem was corrected. I could be wrong.