We did some work and dropped the rear end axle out yesterday to fix pinion angles but when we bolted it all back up there is a vacuum line hanging down that comes straight from the rear axle...
Where should this be at? or tied up to?

 

got a photo?

 

It's not a vacuum line. It's a vent tube line for the rear diff. Should be a fitting on top of the diff or one of the axle tubes, sometimes where the brake line junction is.

 

Its coming from the Axle tube now but just hanging... so it should come from the axle tube to where?

 

It go's into the body someplace. It's purpose is to keep water out of the rear. Some people replace them with longer line and run them higher.

 

....

 

it actually look as if it comes off that brake line splitter

 

it goes through the brake line splitter and into the axle tube.
it is indeed a vent line for your rear axle.
it needs to be tied back up high, stock was in the fuel filler neck/door area.

 

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