Registered: 1453161602 Posts: 833
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I often see broken exhaust studs on the cylinder head on the used BIG REDS I purchase. This was the case for my 85 250ES that I have up on the lift. The bolt was broken off flush with the cylinder head so my options were limited. Luckily on this model BIG RED I can drill the bolt out without removing it from the frame.
This is what I was dealing with after i removed the exhaust Step one was to center punch and then drill the broken bolt. I covered the exhaust port while doing so to avoid metal chips in the head. Once the hole was drilled I sprayed it with penetrating oil and tried an extractor. This did not work and often times it does not but sometimes you get lucky. DO NOT BREAK THE EXTRACTOR OFF IN THE HOLE! If it gets stuck you have another set a problems. I don't like using heat as I am afraid I may warp the head or damage the head gasket. The path forward is to increase the drill size to remove the old bolt and retap. Running the tap in the drilled hole. Take your time tapping the hole and use plenty of lube. Blow out the hole with compressed air when you are done. New exhaust bolt installed.
Registered: 1530501323 Posts: 35
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Option two, if your stud is flush or if it is a little out, grab a old nut and gab a mig welder. Start welding at the center of the stud at a medium/high heat to get good penetration and weld out to fill in the nut. Cool just enough to let the weld cool and back out the stud. The heat loosens the stud, and nut gives you something to hook to. This is a method used by Ford to remove exhaust studs on the 5.4 Ford motor. It doesn't overheat the aluminum because it pulls the heat away from the stud and spreads it out. But use nothing but a mig or Tig for this. Mig is best