After a false start, I found the brake differential valve at American Parts Depot. That completes a full brake overhaul - complete.
We are still having issues with the fuel and temp gauge. I've already replaced the instrument regulator - no joy. We are going to pull apart the dash to see if their is corrosion.
I haven't found a set of used gauges yet but I created an flag so if one pops up I'll get notified.
Looking for a 1969 AMC AMX 140 speedometer - Go Pack
Please post a comment if you can help me find this part.
Thanks