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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Fredward on March 13, 2009, 02:50:39 PM

Title: 8V71 high idle air actuator
Post by: Fredward on March 13, 2009, 02:50:39 PM
The actuator that puts the governor up on high idle was working occasionally and leaking air when actuated. So i took it apart and replaced the O ring on the piston with a standard O ring from my parts bin. Put it back together and tested it; it works better now but still seems to leak a little - I mean I can feel air leaking out of the back end of the actuator. There is a C clip that holds the top on the cylinder but no other seal at that end. Am I missing another O ring or does it require a special flat sided O ring on the piston? Now that I think about it; the O ring on the piston was why the actuator worked intermitently. I must be missing some sort of seal on the end of the acutator where the air line attaches maybe?

Fred
Title: Re: 8V71 high idle air actuator
Post by: Barn Owl on March 13, 2009, 05:32:52 PM
A new piston seal is inexpensive and easy to install. It is more like a cup, and the air pressure helps it seal.
Title: Re: 8V71 high idle air actuator
Post by: luvrbus on March 13, 2009, 05:53:04 PM
 Fredward, do you have Jake's with the high idle cylinder or does your cylinder screw into the governor housing or set on top with a lever
Title: Re: 8V71 high idle air actuator
Post by: Fredward on March 14, 2009, 06:35:46 PM
it screws into the side of the governor. There is also a piston on the top but thats just to keep the accelerator from acuating the throttle.

Also there was no "cup" in there. just an O ring on the piston itself. maybe I'm missing a part?
Title: Re: 8V71 high idle air actuator
Post by: Mrbill4108 on March 22, 2009, 05:36:35 AM
Here are Break down views of the Shut Down & Fast Idle Solenoids.
Hope this helps,
Title: Re: 8V71 high idle air actuator
Post by: Fredward on March 23, 2009, 06:54:44 PM
This is excellent. I might be missing one O ring. I replaced the one on the piston but there is one more on this diagram that I might have missed. By the way it works great now. We're on a trip right now and its working flawlessly.