So the previous owner probably hadn't changed the glow plugs in my brother's truck for about 10 years or so... I am going to be changing them out this week. What are some precautions I can take on these plugs so they don't snap off in the head?
There are not really any actions you can do if they have swollen, but if carbon is a problem then there are ways to work with that. Running it hard seems like it would help, or you might try to use a penetrating oil.
... Or just hope and pray they come out easy LOL
pull a trailer hard before hand to burn off excess carbon and remove them with the engine hot