I just got done working on my uncles SST16 and had to change the actuator on one side because it would not steer in foward. This is the first thing I would check on your mower. Remove the back portion of the mower the part with the seat. and then you can get to the actuators easily. Remove them and check them carefully for any cracks in the rubber. If it has any then replace because this is where the vacuum leak is. Here is the part # from JD AM133406. Cost is $74.20 If you go to the JD website you can View all the technical manuals online for this mower. You can also order the part and they will ship it to your local dealer. If you need any further assistance let me know and I'll try to help.
Last edited by Johnagain; 04-22-2009 at 12:48 AM.
Reason: wording change