I successfully removed the ETA in 2 evenings, totaling 4 hours. JimF's page
http://www.k6jrf.com/MB_asr.html was very helpful, especially the diagram and the warning about the spring running away. I grabbed the spring with locking pliers prior to removal. The vent hose (29), connecting hose (31), gasket (36), and at least one bolt (38) will need to be replaced, because they broke during removal. Next is cleaning, disassembly, and taking many photos.