I've a '90 Autosleeper bus and want to just take a little bit of surface rust off the ledge behind the front bumper but I can't seem to work how how to get it off! It's the big chunky type with a faring type underneath main bumper. I can see the two Allen key bolts on front. Is there any more? Do I have to take faring off too? Sorry for being a bit slow here,..

Any help appreciated
Thanks!