springer problems

Neutering may definitely help. Also neutering will eliminate the chance that your dog developes testicular cancer.  I think it would be a good thing to do regardless!   Are all the dogs intact?  If so it is possible that they are fighting over the female...just a thought.  In that case it might be best to have them all altered.There are more experienced people here that will likely respond with more facts and stuff. But you mentioned the weim and I had to respond...obviously ;o)

I have seen this happen before with a good friend of mine it got so bad that they practically had to live seperate lives, with shifts of one dog in one room with a partner and the other dog in another if you get my drift.
 
You need to do something quickly before things get worse, my friend had both dogs neutered which did help, but the problem was not eliminated.
 
They are probably both being protective of who they see as there owner, I have no advice I just know my friend ended up paying a dog trainer to come in and help her which cost alot.
 
GOOD LUCK!!!!!!   

Also, how did you introduce them?  If you did it on one dogs's home turf - big mistake.  Bigger mistake introducing an intact male to other dogs with whom he does not live, especially if he has not had a lot of exposure (socialization) with other dogs lifelong.  Biggest mistake - not neutering or spaying your dogs if they are not competing and showing in sports or the breed ring.  Pets need to be socialized, trained and neutered!!!!!  'Nuff sed.
If you want to understand this dynamic a bit better, grab yourself a copy of "Feeling Outnumbered? How to Manage and Enjoy Your Multi Dog Household".  Be aware that a dog who puts holes in another dog's neck means business.  And, while it may be only one dog in a lifetime that he means business with, you must always manage such a dog carefully.

Some general points, some of which already were mentioned by spiritdogs:

1. Make sure all dogs are neutered/spade.

2. You cannot change the introduction mistakes we believe you made, therefore, now it is time to countercondition and keep them seperated when nobody is around. Counterconditioning, basically, works by rewarding them and having lots of good things happen while they are together and act nice, whereas those good things do not happen while they are apart. If you are not around, have them in separate rooms or crated.

3. Get yourself some good literature, such as "Feeling Outnumbered" by Patricia McConnell.

4. While at it, make sure you spend some time training them. Basic training and the regular upkeep of these skills has been show to have all sorts of beneficial aspects, not the least of which is that a wide range of behavioral problems are meliorated, even without being directly adressed.

5. Spiritdogs is quite correct that a dog drawing blood is a dog potentially aggressive to other dogs or maybe even humans. You should try to adress this problem before it gets worse, again by discouraging aggression and rewarding nice behavior. Remedial socialization might be needed.

6. Given the previous points, I would advise you to also read something like "The Culture Clash", also by Jean Donaldson. It gives a basic grounding in how a dog learns, how a dog should behave, and how you can get the dog to behave as it should.

If all this seems a bit too challenging or overwhelming at the moment, think about visiting some professional dog trainer in your area. Another good resource is to find a non-profit dog club in your region, where you can meet and make friends with many knowledgable people. Good luck. []

thankyou  all  for your replies, I will keep  you posted on  the result!

a really good way to "defuse" such situations is to teach your spaniel that good things happen when he is quiet and relaxed in the company of the weim. So settle down for some TV, each of you with your dog leashed for safety, and a big bowl of treats. Anytime you notice your spaniel ISN'T staring at the weim, or seems relaxed, praise and feed. Your partner does the same with the weim. When the dogs are doing well with this, try: you pay attention to the weim while your partner showers treats on the spaniel.
 
 
Until you are sure the dogs are fine, keep them confined away from each other. And definitely neuter. It takes some weeks for the testosterone to decline, so you won't notice any immediate effect.