2008 Acura TL service manual calls for a new castle nut and cotter pin when lower ball joint is reinstalled (I'm not replacing lower ball joint). I can't buy a new castle nut locally and wonder if it's safe to reuse the old one if there's no damage after I take it off. It's hard for me to imagine the castle nut is self-locking or anything more special than a regular nut because the cotter pin is the locking mechanism. Is it necessary to get a new castle nut? Why does service manual ask for a new one?

#14: Nut, Castle (12mm) 90363-SEP-A00



#14: Nut, Castle (12mm) 90363-SEP-A00

 

Good question.

Having worked on these honda's for a long time. when you try to re-use the castle nut, youll find that it does NOT thread back on nicely, without the threads binding.

My guess is that because of the broken threads of the "castle" profile, and the LARGE amount of torque this nut goes thru, the threads stretch relatively. So it just doesnt tighten back on like its new. You CAN use a impact to drive a used one back on, works fine. but its really meant to be 1-time use.

Having gotten into the habit of simply buying NEW castle nuts, they thread fully finger tight without binding. No messing around, and hand tools are ok.

 

That's just plain installation error. The threads do not stretch or bind.

 

Next time I chase threads on an old nut with a new tap, I'll take a picture and prove you wrong.

But go ahead, call it installation error. And don't listen to instructions.

Or give it a shot and buy a new nut. You'll see it works better.

 

Moog ball joints usually come with a new castlenut

 

44ft*lbs is not going to stretch the threads on an M12 bolt. You have gone Wwwwaaaayyyy beyond the torque spec if you have messed up the threads.

Only time I have thread problems is when the ball joint is really stuck and the the ball joint press smooshes the the tip of the threads or blows out where it is cross drilled.