diff --git a/tempest/lib/services/volume/v3/attachments_client.py b/tempest/lib/services/volume/v3/attachments_client.py
index 303341e..ef8be37 100644
--- a/tempest/lib/services/volume/v3/attachments_client.py
+++ b/tempest/lib/services/volume/v3/attachments_client.py
@@ -31,5 +31,6 @@
         """Delete volume attachment."""
         url = "attachments/%s" % (attachment_id)
         resp, body = self.delete(url)
+        body = json.loads(body)
         self.expected_success(200, resp.status)
         return rest_client.ResponseBody(resp, body)