I see you have to either clamp off the fuel lines or put a bolt to keep the diesel from flowing out. I dont want to clamp it because I have not yet replaced the lines and I dont want to damage them. What size bolts do you use to stick in the lines to prevent leakage? The car is an 84 300sd by the way...

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1984 300SD Orient Red/ Palomino
1989 560SEC
2016 Mazda 6 6 speed manual
1995 Ford F-150 reg cab 4.9 5speed manual