(asp.net) WCF problem with service reference update

I have a ServiceContract with N OperationContracts. When I add a service reference in my web app it works just fine. Now the following situation, I add for example 3 another OperationContracts to my WCF services, after that I get the HTTP 400 Bad Request. The problem is not in the operationcontracts, but it seems it's in the size of the generated proxy. For example if i comment another operationcontracts, than it works well. Did anybody had problems with that, if so give me pls an indice, because by googling I didn't succeed in finding a good response.