diff --git a/gunicorn/http/tee.py b/gunicorn/http/tee.py
index 540ecfd4..fe1fbacd 100644
--- a/gunicorn/http/tee.py
+++ b/gunicorn/http/tee.py
@@ -172,7 +172,7 @@ class TeeInput(object):
         if any."""
 
         if self.parser.body_eof():
-            del self.buf
+            self.buf = StringIO()
             self._is_socket = False
 
     def _tmp_size(self):