Big Paws Only Dog Forums

Hi Everyone,
I have an issue with my Baby and I hope someone can give me advice.  Maybe I should be posting under training but, I think maybe other Saint parents have had the same issue.  Brutus is ten months today! He is a very happy go lucky dog that loves everything and everyone.  The problem is he has no concept of his size.  Whenever he sees a small dog he wants to play with it.  The problem is he's now 140lbs. with huge paws and a huge jaw.  He's a bit rough and mouths at them.  They get scared and the owners freak out thinking he's going to kill them.  The owners panic and usually pick up there small dog and this gets Brutus even more excited and he bounces at the owner trying to nip the small dogs tail.  He doesn't appear viscious.  Just excited and curious about the small dog.  At the dog park he always perfers to try and get the little dogs to play.  He doesn't really care so much about the middle to large dogs.  If we are out and about on leash and he sees a small dog I need to put him in a sit stay (which he does very well, although he howls and crys about it!)  If I don't put him in a sit stay then he tries to drag me over to see them.  We have a cat at home to and he's the same way with him.  Everytime he sees him he paws at him and mouths him.  He just loves him.  What I am afraid of is that he will accidently kill a small dog (or our cat).  What can we do to teach him that they are off limits or at least to be gentle?  Any advice would be great!

Brutus was off leash with a Rottweiller friend today when the Rotti visciously attacked a small white dog. ( the dog is ok. but in major shock).  Brutus didn't join in right away but when the white dog ran towards him he did grab at him and bite him on the neck.  We figure he was copying the rottie. Brutus has always been very kind but we're afraid him witnessing this act of violence might make him mean.  He didn't seem to understand it wasn't a game.  Any ideas where to go from here? I'm afraid to let him offleash.

Brutus is now 5 months old and is not totally housebroken.  We don't know what to do we are sooo frustrated!  The good news is he won't go in the house.  If he's in the actual house part then he asks to go outside.  But....he goes all the time in our attached garage!  This is causing our foyer to reek.  It's not the most appealing greeting for our guests!  We have tried removing the scent using Nature's Miracle. Putting him in a crate (he just howls forever which the neighbors don't appreciate), and taking him out to pee late at night and early in the morning.  (The garage is where he sleeps). Nothing has worked! Any suggestions?  I contacted a trainer today and he said for $80 he's tell me what to do.  I thought I'd check with people on the board first. Help!