I'm in the process of taking apart the dash on my 280 SEL, and I'm having some trouble getting the gauge cluster out. I've read all the posts about the engine temp gauge and the capillary tube connection thing and that I need to remove the sender from the engine connection and then thread it through the firewall. I'm having a hard time unscrewing the sender from its connection to the cylinder head and wanted to make sure I doing this right. There seems to be two bolts threaded into each other, one a 14mm bolt and the other a 19mm bolt. I can't for the life of me get the 14 mm to loosen, almost impossible to even get a combo or a flare nut wrench down in there. Are these two bolts welded together, do I need to loosen the larger 19mm bolt? Is there a way to remove the gauge from the cluster and leave it still attached to the engine? I only need the speedometer out, I'm having the odometer fixed. Any advice?