Vacuum problem

[Prorider]

I just noticed the other day my auto hubs are not locking when I put it in 4x4. Also the a/c is coming out the defrost. Then today I tried them again and they both worked correctly. Trying to figure out if its the vacuum pump or the phv solenoid or whatever that's called. Thanks for any help

[twoicebergs]

This is what the vacuum pump sound like from close up.You should hear it on most cold start-ups. If you bleed-off the vacuum, it should start running.

Powerstroke 6.0l Pre-start noise - YouTube

Powerstroke 6.0l Pre-start noise - YouTube

[dguts08]

Follow the vac lines down and spray shaving cream over them, if you have a leak in the lines which is common it'll start sucking the shaving cream in and you can replace that line. The shaving cream won't wreck anything either

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