pesky buggers they are
Are you using the made for adjuster spanner/socket of just a normal spanner or shifter

. The adjuster can be a problem as they rust them selves in..so when you try and get them out you round the end..Not Good...Spray with plenty of WD from both side..soak itr real good and try again
When you get it out..check the other end also.. but it maybe a good idea to get replacement anyway..do Both sides while your at it!!!!
and when you are replacing it..get a tub or copper grease and smear a good amount on the thread..and you will never have a trouble agian
