Brakes line Test Line Thread Sizes??

[Transom Jack]

I am having problems with my antilock brakes on my 1990 Chev 1500. I would like to install some test jumper brake lines to bypass the antilock actuator to check and see if its the actuator or the master cylinder. Does anyone know the thread sizes on each end of the brakes line I will need to make up the test line? I will be down without a car to run back and forth to the parts store so I would rather make the initial trip and get the right sizes to start with...... parts store is over 2 miles from the house..... would be a long walk

 

[Swims350]

blf-19c, I think it's 7/16 to 1/2 inveted flare fitting, remove the line that goes to the dump valve, install the fitting on it, remove the line from the dump valve to the prop. valve, install the line that used to go from the frame of the truck to the dump valve(the one first removed) install that now right into the prop. valve. I just did this on my 88. I got the part number from another guy who did it to his. I haven't bled mine to test yet though.

No test line needed just that adapter fitting and then some bending of the stock line to make it match up to the prop. valve.