diff --git a/scrapy/trunk/docs/ref/settings.rst b/scrapy/trunk/docs/ref/settings.rst
index 5881aaa96..e8fc2d52d 100644
--- a/scrapy/trunk/docs/ref/settings.rst
+++ b/scrapy/trunk/docs/ref/settings.rst
@@ -400,9 +400,6 @@ Default::
         'scrapy.contrib.spider.reloader.SpiderReloader',
         'scrapy.contrib.memusage.MemoryUsage',
         'scrapy.contrib.memdebug.MemoryDebugger',
-        'scrapy.contrib.pbcluster.ClusterWorker',
-        'scrapy.contrib.pbcluster.ClusterMasterWeb',
-        'scrapy.contrib.pbcluster.ClusterCrawler',
         'scrapy.contrib.closedomain.CloseDomain',
         'scrapy.contrib.debug.StackTraceDump',
         'scrapy.contrib.response.soup.ResponseSoup',
diff --git a/scrapy/trunk/scrapy/conf/default_settings.py b/scrapy/trunk/scrapy/conf/default_settings.py
index d8a55d0f6..60e9e3b1f 100644
--- a/scrapy/trunk/scrapy/conf/default_settings.py
+++ b/scrapy/trunk/scrapy/conf/default_settings.py
@@ -96,9 +96,6 @@ EXTENSIONS = [
     'scrapy.contrib.spider.reloader.SpiderReloader',
     'scrapy.contrib.memusage.MemoryUsage',
     'scrapy.contrib.memdebug.MemoryDebugger',
-    'scrapy.contrib.pbcluster.ClusterWorker',
-    'scrapy.contrib.pbcluster.ClusterMasterWeb',
-    'scrapy.contrib.pbcluster.ClusterCrawler',
     'scrapy.contrib.closedomain.CloseDomain',
     'scrapy.contrib.debug.StackTraceDump',
     'scrapy.contrib.response.soup.ResponseSoup',