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Discussion Starter · #1 ·
Hi together,

after the last inspection (change of engine mount, engineoil and transmission oil) i have a very bad noise from my vacuum pump.
When i push the brake pedal 4 or 5 times, the pump works and it's very loud. :eek:
Here you have a youtube clip.
https://www.youtube.com/watch?v=lfJqBl87g04 (My girlfried pushed the pedal)

Some tests i did:
Ignition and engine off, wait a little bit, push the pedal and hold it. The pressure is okay. When i pump 3 or 4 times the pedal becomes hard.
When i start the engine now, the pump works and makes vacuum. I hope i can exclude the brake booster.
There are no entries in fault recorder and the abs stil works.

Any idea?
I can't believe that the pump is the problem, but rather some vacuum hoses.

Thanks lot and have nice evening.
Daniel
 

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That's frequent when we are looking for noise . . . but unfortunately the pump noise is "normal". You just didn't noticed it too much when everything was running smoothly.
They could have picked a quieter one for sure!
Yes the pump will turn on when pushing the brake pedal. It's an air vacuum assist to the brake system which is especially but not solely used when the engine is turn off.
If it works correctly it will turn off after a short moment of brake pedal inactivity.

. . . probably one of my least favorite part of the car for sure :p
 

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Discussion Starter · #3 · (Edited)
Hey TG,
thank you for reply.

Ähm... i definitly never heard this loud sound before. Never...
It's correct that the pump makes a "summmm" if i turn the stearing wheel.. but this is not normal :eek:
I'm standing every time on brake pedal when i start the car (ex auto transmission driver..) and this noise comes from one day to another.
Can i take a servie on the pump? Is there a magnetic switch inside?
 

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And please, anyone, correct me if I'm wrong...
 

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Mine sounds like that. It's most noticeable if you turn the key to pos II and wait a second before starting. It seems loud with the hood open, but I've never heard it while driving normally. I assume that the great deal of weather stripping in the hood and our nice mechanical tappets mask the sound nicely.

The throttle body also makes some interesting sounds with the engine off, but again, totally masked by engine noise.
 

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Discussion Starter · #7 ·
When i start the car while pushing the brake pedal the pump is making this noise... this was not before.
And when i drive backward out of the carport and brake three or four times, the pump make the noise also..
It feels a little bit that the engine (or whatever) can't generate enough vacuum. BUt, how i can check this?

Secretly i hope somebody steal this scrap metal..
 

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When i start the car while pushing the brake pedal the pump is making this noise... this was not before.
And when i drive backward out of the carport and brake three or four times, the pump make the noise also..
It feels a little bit that the engine (or whatever) can't generate enough vacuum. BUt, how i can check this?

Secretly i hope somebody steal this scrap metal..
So what you are saying is that it runs more often then you remembered, in conditions that you think it normally should not be running . . . (?)
You could have an air leak on one of the hose or fittings.
Look for cracks on hoses and fittings leading to the pump.
You might want to do a vacuum check...
 

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Discussion Starter · #9 ·
Hm, can i do a vacuum check myself?
Did anybody have a hose diagram for the vaccum hoses?

Can i change the one-way valves on the hoses?

Is it correct that i disconnect the vacuum hose on the splashback only with a pull?

I relly don't know whre i can start to find the failure :(

On the first photo the vacuum connector which i can pull out.
http://dbrenner.de/gallery3/index.php/Volvo/P1010002-3

2nd:
http://dbrenner.de/gallery3/index.php/Volvo/2012-03-13_18-13-43_562
How i can unplug the hose from the pump? And can i get the valves as single items?

Thank you very much!
Daniel
 

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Read through this thread.

How i can unplug the hose from the pump? And can i get the valves as single items?
Squeeze hard & pull. If it doesn't come you haven't squeezed hard enough or in the correct area.
No, most of the valves (like the one circled) come with the hose assembly.
 
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