Dying Vacuum Pump

[BrianX128]

Just wanted to get some opinions. I think my vacuum pump is on the way out. Won't pull more than 20 at idle, takes more or less wot to get to 30. Doesn't recover well from brake booster being used. Here's a video.

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I can't find any leaks. Hvac doesn't change behavior and ive pinched all of the lines off the vacuum tree and nothing seems to help it. Hard to test with the brake booster but pinching that line when it was barely at 10 at idle didn't help 8t build vacuum any faster so doesn't seem to be an issue there either.

Thoughts?

 

[Olds64]

It looks like your truck is idling at 5"-10" of Hg. In my book your vacuum pump is dead. The VRV on C6 trucks needs at least 13" of Hg to shift properly. I installed an AutoMeter vacuum gauge on my Bullnose truck since I already had the VRV and C6 rebuilt.

Here's a thread that covers Ford instructions on adjusting a VRV.

https://www.oilburners.net/threads/vrv-adjustment.64130/

 

[cbrown]

Look at inches not cm.

Disconnect the 3/8 hose from the pump at the pump and connect gauge there. You must see at least 15 INCHES vacuum at idle or pump is bad. 15 or more inches at idle at pump...you have a leak to track.

 

[DirtyWood]

IIRC 25 inches of vacuum at idle is the specification. I've tested two new vac pumps and both pulled 25-27 inches at idle measured at the pump.

As far as replacement pumps go I don't think there is a clear winner and they're all a bit of a crap-shoot.

 

[BrianX128]

Ok the pump is definitely the issue. Vacuum fluttering at idle with nothing even hooked except the gauge. Needs 2500 rpm to hold 25 inches of vacuum and if rpm drops so does vacuum. I guess I just buy a random pump and hope for the best?

 

[WMO4IDI]

Ok the pump is definitely the issue. Vacuum fluttering at idle with nothing even hooked except the gauge. Needs 2500 rpm to hold 25 inches of vacuum and if rpm drops so does vacuum. I guess I just buy a random pump and hope for the best?

Flush the oil in it and fill with quality gear oil, it's the common weak point of most vacuum pumps.

 

[Nero]

And if you get a new pump... Make sure it has oil!

 

[Olds64]

I didn't know our vacuum pumps required oil. I've had at least 2 die on me in the 9 years I've owned the truck. Here's a good thread:

https://www.oilburners.net/threads/vacuum-pump-oil.87095/

Maybe I should have checked the oil fill in those vacuum pumps before I replaced them.