For a couple of summers I helped a very prominent dog trainer (who is now the host of a duck/goose hunting show) train labs for retrieving purposes (field trials, hunt tests, and just hunting purposes). This guy took a dog and won gold in the Super Retriever Series on ESPN in 2005, so he knew what he was doing. Labs are very responsive and habit forming, so seeing the older dog do its business correctly (and being rewarded) will help. IDK if you've ever noticed or not, but we have found that a male dog will still squat to pee all of his life until he sees another male dog lift his leg. I've bot a 7 year old lab that still squats because all we have are females.
I've never house trained a lab like this, but something that we've used on our house dog (miniature schnauzer) is a squirt water bottle. Typically if you don't like using a good swat of the the hand or a newspaper, this works pretty good. You just have to make sure the dog knows what it is getting punished for. In the past I have had better luck trying to catch the dog in the act and punishing it right after (basically the same thing we do with retrieving). If you try to punish the dog a few hours after it has used the bathroom in the house (like you're coming home from work), the best thing we've done is let the dog know why we're punishing by "putting their nose in it."
That's all I've got for now. If you have any questions, message me.
#S#
Josh
