Tomcat stops responding

We are having issues running Jahia 4.1.1 in production. We recently 
upgraded our servers to Red Hat ES 4 and added apache 2.0.52 with mod_jk 
1.2.20 to front  end the whole thing. Under load the server stops 
responding to requests. Here are the settings for workers.properties, 
server.xml, and httpd.conf

worker.properties
============
  worker.list=consumer,builder
 
# Set properties for consumer (ajp13)
  worker.consumer.type=ajp13
  worker.consumer.host=localhost
  worker.consumer.port=8019
 
  worker.builder.type=ajp13
  worker.builder.host=localhost
  worker.builder.port=8009


httpd.conf
=======
<IfModule mod_jk.c>
    JkWorkersFile conf/workers.properties
    JkShmFile    logs/mod_jk.shm
    JkLogFile    logs/mod_jk.log
    JkLogLevel   info
    JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
</IfModule>

<VirtualHost *:80>
...
    <IfModule mod_jk.c>
        # Send everything for context /examples to worker named worker1 
(ajp13)
        JkMount  /jahia/* builder
        JkMount  /pdfgenerator/* builder
    </IfModule>
</VirtualHost>


server.xml
=======
<Connector className="org.apache.ajp.tomcat4.Ajp13Connector"
               port="8009" minProcessors="5" maxProcessors="75"
               acceptCount="10" debug="0"/>

What settings are other people using in production?