If you have followed procedure and all has been disconnected in the car and under the hood, then I will say that we have had to use prybars to release the box from the firewall on 124's. Please make sure all parts have been disconnected before using a leverage device.
1987 190E-16v, 1988 260E Gone after 19 years of service,
2006 C280 4MATIC for the Wife
2006 OM647 Dodge (Mercedes) Sprinter with wheelchair access for my#2 Son
21 years Mercede-Benz Technician, Master Technician/Master Wrench
Master Guild Technician once/ SLR Technician