Haven't adjusted them in a while, now the top collar is stuck, any ideas on how to free collars up?

 

Try cleaning the threads with a stiff brush, then coat it with oil and let it run down and soak the collars.

 

^x2 also liquid wrentch or wd-40 is good also.

 

2 of the 4 of mine were stuck also.

1) I tried to use both wrenches to turn it at the same time.

2) I also tried to set the wrench and hammer it.

3) Tried putting a flat head screwdriver in one of the sockets and hammering it.

4) I pretty much soaked it with WD-40.

5) I used a torch to heat up the rings (dont do this at home boys) that didnt work

One of the 2 stuck suspension, I used an impact hammer and FINALLY GOT THE DAMN TOP RING TO MOVE.

The second one was more stubborn, I ended messing up one of the sockets, and I got so fed up, so I used a grinder and cut the ring, I was then able to slighty pry it open and turn it.

Hope this helps! And hope you dont have to end up cutting the ring like I did!