How come some items says "maintain" and other items say "repair" what's the difference. How come my combat armor says press triangle (ps3) to maintain but the option is greyed out while another piece of combat armor says repair instaed of maintain?

Anyone?

If the item is a high enough condition, above the little notch in the condition bar, it is currently suffering no penalties whatsoever. This is like at 50% for armour and 80%(?) for weapons. You can still bring the item up to 100%.. but it just helps keep the weapon in good order (i.e. "maintain"). If the bar is below the notch, it is in disrepair and is suffering penalties and a a chance to malfunction, and so you need to "repair" it. The effect is exactly the same, though: raise the condition of the item. It's just letting you know quickly which ones are in disrepair and which items are not (but can still be made sturdier).

How come the "maintain" option is greyed out for the combat armor even though its not at 100%?

You need another identical item in your inventory from which you can scavenge parts. .. or, if you do have an identical item, possibly your repair skill is not high enough.

I have two sets of combat armor and repair skill of 53.