Name that part!

[64MCI]

Hello again!

I got home from a trip yesterday and before moving my bus to it's normal parking spot, I got an air leak that won't allow the bus to build air pressure.

This is the view in front of the rear axle on my MC5. First question, is the blue assembly/part the inversion valve?
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Here is the spot that is leaking all my air.
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Assuming it is the inversion valve, I've read some folks rebuild them and some replace the whole thing. What say you?

Thanks!