OK here is the deal last year the castle nut on my lower ball joint came off. Yes during a turn. I had ball joint replace along with other items. Well the nut came loose again on new joint I tightened it back on installed a new cotter pin. This lasted about 6 months now the nut has worked its way loose again. Each time it has sheared off the cotter pin so it is not the pin comming out. Has anyone ever had this problem or know what the cause maybe. It is only on the driver side.

 

Well, it wouldn't be a bad idea to put some loctite on it for the time being. That would prevent it from backing out.

I can only think of a few things causing it to back out: excessive vibration and/or you're not tightening the nut enough.

 

I thought that it was not tight enought the first time it happen so I did ensure it was tight enought. Thanks

 

is the nut hitting something? Is the lower arm damaged where it goes through? It's not going to loosen up by itself, and it sure isn't going to shear the cotter pin by itself.

 

dont use the standard cotter pin that comes with the kit then. go to a hardware store and buy a stainless steel one. it wont rust and get weak and it will have a higher tensile strength to begin with.

this may be a solution to an issue you having but it will not fix the problem that is causing the issue. you need to figure out why this is happening and fix that issue as well. most of us cant get the lower ball joint separated when we want it to happen let alone when we dont want it to happen......
adam jeffery