diff --git a/openstack/network/v2/router.py b/openstack/network/v2/router.py
index 6abcac108..87edb27fc 100644
--- a/openstack/network/v2/router.py
+++ b/openstack/network/v2/router.py
@@ -75,6 +75,16 @@ class Router(resource.Resource, resource.TagMixin):
     #: Timestamp when the router was created.
     updated_at = resource.Body('updated_at')
 
+    def _put(self, session, url, body):
+        resp = session.put(url, json=body)
+        if not resp.ok:
+            resp_body = resp.json()
+            message = None
+            if 'NeutronError' in resp_body:
+                message = resp_body['NeutronError']['message']
+            raise SDKException(message=message)
+        return resp
+
     def add_interface(self, session, **body):
         """Add an internal interface to a logical router.
 
@@ -83,9 +93,11 @@ class Router(resource.Resource, resource.TagMixin):
         :param dict body: The body requested to be updated on the router
 
         :returns: The body of the response as a dictionary.
+
+        :raises: :class:`~openstack.exceptions.SDKException` on error.
         """
         url = utils.urljoin(self.base_path, self.id, 'add_router_interface')
-        resp = session.put(url, json=body)
+        resp = self._put(session, url, body)
         return resp.json()
 
     def remove_interface(self, session, **body):
@@ -96,21 +108,13 @@ class Router(resource.Resource, resource.TagMixin):
         :param dict body: The body requested to be updated on the router
 
         :returns: The body of the response as a dictionary.
+
+        :raises: :class:`~openstack.exceptions.SDKException` on error.
         """
         url = utils.urljoin(self.base_path, self.id, 'remove_router_interface')
-        resp = session.put(url, json=body)
+        resp = self._put(session, url, body)
         return resp.json()
 
-    def _put(self, session, url, body):
-        resp = session.put(url, json=body)
-        if not resp.ok:
-            resp_body = resp.json()
-            message = None
-            if 'NeutronError' in resp_body:
-                message = resp_body['NeutronError']['message']
-            raise SDKException(message=message)
-        return resp
-
     def add_extra_routes(self, session, body):
         """Add extra routes to a logical router.
 
diff --git a/openstack/tests/unit/network/v2/test_router.py b/openstack/tests/unit/network/v2/test_router.py
index 560d0ea42..a5cd05326 100644
--- a/openstack/tests/unit/network/v2/test_router.py
+++ b/openstack/tests/unit/network/v2/test_router.py
@@ -11,6 +11,9 @@
 # under the License.
 
 import mock
+import testtools
+
+from openstack.exceptions import SDKException
 from openstack.tests.unit import base
 
 from openstack.network.v2 import router
@@ -173,6 +176,37 @@ class TestRouter(base.TestCase):
         sess.put.assert_called_with(url,
                                     json=body)
 
+    def test_add_interface_4xx(self):
+        # Neutron may return 4xx, we have to raise if that happens
+        sot = router.Router(**EXAMPLE)
+        response = mock.Mock()
+        msg = 'borked'
+        response.body = {'NeutronError': {'message': msg}}
+        response.json = mock.Mock(return_value=response.body)
+        response.ok = False
+        response.status_code = 409
+        sess = mock.Mock()
+        sess.put = mock.Mock(return_value=response)
+        body = {'subnet_id': '3'}
+        with testtools.ExpectedException(SDKException, msg):
+            sot.add_interface(sess, **body)
+
+    def test_remove_interface_4xx(self):
+        # Neutron may return 4xx for example if a router interface has
+        # extra routes referring to it as a nexthop
+        sot = router.Router(**EXAMPLE)
+        response = mock.Mock()
+        msg = 'borked'
+        response.body = {'NeutronError': {'message': msg}}
+        response.json = mock.Mock(return_value=response.body)
+        response.ok = False
+        response.status_code = 409
+        sess = mock.Mock()
+        sess.put = mock.Mock(return_value=response)
+        body = {'subnet_id': '3'}
+        with testtools.ExpectedException(SDKException, msg):
+            sot.remove_interface(sess, **body)
+
     def test_add_extra_routes(self):
         r = router.Router(**EXAMPLE)
         response = mock.Mock()