I have had a lot of luck with Pin Keepers they are sold in most Harley Davidson Shops. Basically the are a small round tube with a set screw. I push the pin keeper very hard from the back and tighten down the set screw and it seams to work for me. A pack of 12 is about $5.00.
Here is a link you will have to copy and paste it in.
http://www.stockpins.com/pin-guards-...FUmA5QodV1g7vQ