Reply With QuoteHi --- I've always tightened it pretty snug and then backed it off just a little bit. Here's some "directions" I found on a google search:
Install Washer and Nut:
Next, install the spindle washer and tang washer (if necessary).
Then install the castle nut.
Tighten the nut until it stops or becomes snug.
Rock the hub and push in to make sure the hub is fully seated onto the spindle.
Then tighten the castle nut a little more.
http://www.etrailer.com/Merchant2/gr...nut_pb_150.jpgFinal Castle Nut Adjustment:
To make sure the hub is seated properly, back off the castle nut until it is loose.
Then tighten the castle nut snugly until it stops.
Look to see where the cotter pin hole lines up with one of the notches on the nut.
On hubs that use the tang washer or cage to lock the nut, you will have to do this by sight.
Then back the nut off one notch, so that the cotter pin will fit through the castle nut.
Install the cotter pin and then spin and rock the hub.
When you rock the hub you should feel the hub barely moving front to back.
Try experimenting by loosening the castle nut one more notch to feel the difference in the play in the hub.
Then install the wheel and rock the hub again.
On the outside edge of the tire, the movement should not be more than 1/4" inch.
Any play should be barely noticeable.
When you are satisfied with the adjustment, secure the cotter pin.
Push the pin through the hole on the end of the spindle and through the notches on the nut.
Then split the bottom of the pin to the left and right.