Full manual brakes after vacuum pump gasket replacement.

[BradyBoi55]

I recently just replaced my vacuum pump gasket and no longer have boosted brakes. There are no leaks around the pump. I’m wondering if I have a vacuum hose hooked up incorrectly. I removed the pump completely off to clean it so that is why I had the lines off. Thanks!

[Theiceman]

Well the main purpose of that pump is to provide vacuum for your brakes so I would recheck your work.

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[BradyBoi55]

I did recheck it and I didn’t notice any problems. After driving it home I am currently throwing a code for running lean. I checked the vacuum line from the brake booster and it is on correctly but has not vacuum whatsoever. I pulled the line off while at idle and there was no vacuum.

[Spawne32]

I did recheck it and I didn’t notice any problems. After driving it home I am currently throwing a code for running lean. I checked the vacuum line from the brake booster and it is on correctly but has not vacuum whatsoever. I pulled the line off while at idle and there was no vacuum.

Then recheck your work.

[BradyBoi55]

The line the continues past the big line from the brake booster that connects to the passenger side of the vacuum pump moves to a 3 way split. To make sure I have it right where does the lines continue? I have one hooked up to the small plastic connecter on the back of the cylinder head near the coolant flange and the other one is plugged into the purge valve by the intake manifold(I believe)

[Theiceman]

See if you are generating from the pump first. Should be crating vac even at idle.

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[BradyBoi55]

Will I be able to feel the vacuum at idle? Also where should I test the vacuum on the pump to make sure it is functioning properly.

[Theiceman]

Will I be able to feel the vacuum at idle? Also where should I test the vacuum on the pump to make sure it is functioning properly.

The nipple that comes right out of it .

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[BradyBoi55]

Will I be able to feel the vacuum at idle? Also where should I test the vacuum on the pump to make sure it is functioning properly.

What is the operation of the vacuum pump? Is it always running or just running while the car is in boost? Also how does is it correlate with the HPFP? I know the hpfp is spring loaded and driven off of the cam and the vacuum pump spins from the camshaft.

[BradyBoi55]

The nipple that comes right out of it .

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So now I’m leaning towards the vacuum pump is bad. There in no vacuum at idle coming from the nipple. Could a bad pump cause the car to run lean at idle?

[Spawne32]

So now I’m leaning towards the vacuum pump is bad. There in no vacuum at idle coming from the nipple. Could a bad pump cause the car to run lean at idle?

Yes because you are sucking in fresh air into the crankcase through the vacuum pump seals now.

[Smac770]

Pierburg video, you have to crank the volume - https://youtu.be/mp3NeWuEDk8
Actual unit - https://youtu.be/fWATwtqCEXw

But neither of those actually explain anything. This video was the actually informative one - https://youtu.be/toursbNKM90

Interesting that it talks about the pump mixes the air and oil and then dumps the oil to the oil separator. I always assumed the oil port to the vacuum pump was just for lubrication of the vane and HPFP tappet. But that would explain the single air port and single oil passage; they combine and are dumped back out the center to the head on to the oil separator? That probably works, because once evacuated, how much air will really be pulled out of the system? (well, unless you have OP's situation of a possible air leak)

[BradyBoi55]

I was able to do some tests today. I think the gasket might not be sealing 100%. I felt ksome vacuum around the gasket and I put my finger over part of the gasket and my other finger over the black nipple on the passenger side of the vacuum pump and felt a very slight vacuum.

[Theiceman]

I was able to do some tests today. I think the gasket might not be sealing 100%. I felt ksome vacuum around the gasket and I put my finger over part of the gasket and my other finger over the black nipple on the passenger side of the vacuum pump and felt a very slight vacuum.

That's exactly what it is.. the wiper has to make a perfect seal.. and all has to be perfect . Take it all off and do it over.

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[Theiceman]

The pump is very simple.

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