I have never had much trouble on either my 1520 or T1520. I have always used a channel locks. Some kind of a spanner wrench might work better. To get a little extra room in order to get a better bite with the channel locks, you might try removing the single bolt that holds filter assembly to its mounting bracket. That will allow you to pull it out a bit where you might be able to get a better bite with your channel locks. Use a second channel locks, if needed, to hold the housing and be careful to not damage the filter housing. Lastly, you can remove the fuel lines from the housing and get the whole filter assembly off the tractor to gain lots of room. I usually put a dab of anti-seize on the retaining ring threads to help it come off easier next time.
