I take 2 or 3 electrical tie-wraps with me as a back up suitcase lock.
They may not be as strong as a decent travel padlock but are cheap and easy to use if you have to replace a broken padlock while away.
one or two things to remember -
1 don't lock up the case until you really have to - unlike a padlock these are single use only!
2 you will need a small knife or scissor to cut the tie-wrap to open your case - may not be a problem when you get home, but could be a little difficult at the airport - don't forget no sharp items in your cabin luggage.