Ebbflow,
Am I understanding correctly that you have 3 wheels on one line (circuit) and 1 on the other? If you have a leak in the 3 wheel line you only have on wheel stopping the truck...this is not safe as the truck will pull very hard in that direction!
Are you running disc brakes on the front and drum on the rear or all drum?
Did your MC come with a Combination Valve (Metering, Pressure Differential and Proportioning)? If so I would change the lines so you have a separate line to each front wheel and one common line to both rear wheels. If you are running all drum than you should have one pot on the MC do the front and the other do the rear.
Since you have the MC down now might be the perfect time to replace all of the steel and rubber lines.
Mike B
