JRscooby wrote:
I have cut off and replaced some couplers, but a 10 year old trailer? Sounds like a lot of abuse, or more likely neglect. If it was mine, I would first spray it with WD-40, and see if it loosened. (Yes, there is better stuff, but most people have a can around) Most likely it will work better, and that will tell you to save some money. Remove the guts, clean up rust and caked lube. Re-lube, put back together, and adjust.
BTW, if it is abuse, instead of neglect, might look at replacing with a eye, instead of coupler.
Sounds more like a typical cheap coupler choice from the frame manufacturer to me rather than accusing the owner of neglect and abuse..
Not ALL couplers are of good quality and/or construction.
Not ALL couplers can be torn apart and repaired or adjusted.
Not ALL couplers will live 50 yrs or more..
One must set expectations a lot lower now days as there is a lot of cheap couplers on the market compared to 20, 30, 50 yrs ago..
OP may have simply run into one of those cheap couplers and the fix most likely is to have the old one cut off and a new one of better quality welded in place.