I have a set of sockets that have the hex key in them.
You can spray it with something to try to get it to break free easier or to lossen the bolt, but a good hex socket and a 18 inch breaker bar works wonders. Slow even pressure, no brute strength needed.

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Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red