It's a medium duty truck but it doesn't have air brakes. I have a torque multiplier but it is missing its original handle and I was using a piece of 3/4 steel rod as a handle. I only succeeded in bending the rod when I started putting pressure on the breaker bar. Perhaps with a better handle, the torque multiplier might work but I think I really need the hammering of an impact wrench as Brian noted.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13