I'm removing the glow plugs from my 606 engine. Three of them, 3, 4 and 6 were removed easily, as if they had been installed yesterday. Nos. 1, 2 and 5 are being difficult.

I'm working on #2 now. It appears to be fully unscrewed from the threads, but it is still difficult to turn and won't slide out. Is it possible that there is some corrosion on the shaft below the threads that is making it difficult to withdraw? The others looked fairly clean, although one was a non-functioning plug.

Anyone deal with this issue before? Any suggestions for how to resolve this?

Regards,
Tom