What is this hose...vacuum line?
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What is this hose...vacuum line?
I broke this while replacing my valve cover gaskets. At the time I thought it was part of the windscreen washer system because it appears to come from underneath the reservoir. But on closer inspection I'm no longer confident of that 
I noticed that after the engine had been warm for a while, the brake pedal got quite hard. It still works and is definitely still power assisted, but less so than normal. The problem seems to come and go. That's what made me think this might be a vacuum line. It's hard to tell where it goes but it looks like it attaches to those devices on the metal bracket just above the throttle body (lol I don't know what those things are either)
Here is one broken end:
And the end of the main part:
And here's the part I broke off. Originally I just broke the pipe in one place, but when trying to trace where it went a couple of complete pieces just came off in my hand. It's like egg shell
Can anyone tell me what it is? Thanks!
I noticed that after the engine had been warm for a while, the brake pedal got quite hard. It still works and is definitely still power assisted, but less so than normal. The problem seems to come and go. That's what made me think this might be a vacuum line. It's hard to tell where it goes but it looks like it attaches to those devices on the metal bracket just above the throttle body (lol I don't know what those things are either
)Here is one broken end:
And the end of the main part:
And here's the part I broke off. Originally I just broke the pipe in one place, but when trying to trace where it went a couple of complete pieces just came off in my hand. It's like egg shell
Can anyone tell me what it is? Thanks!
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You can check this by revving the idle above 4,200 rpm's and look at the actuator arms for movement in the front of the mainifold.
I should have specified my engine - it's a '98 2.8 30V. Does it have this mechanism? I read about something in the Bentley manual that sounded like the above but it was for the 3.0 only: "Plastic two-position variable intake manifold..."
Anyway I have got some fuel hose from Ace Hardware that fits neatly over the broken hose so I was thinking I'd give that a try.
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I'm sure you have it
The manifold change over spool valve is on all 2.8 engines, there are two vac actuators with two short ball end arms that rotate the spool.
Look again at the front of the manifold.
Look again at the front of the manifold.
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I'm going to correct myself
The IMT (Intake Manifold Tuning) part on the 2.8 has one vac actuator or solenoid not two like the 4.2 and 3.0, the manifold spool is under the coil
pack in front of the manifold.
Here is a vac diagram to help.
PDF not so good, I'll try again.
pack in front of the manifold.
Here is a vac diagram to help.
PDF not so good, I'll try again.
Last edited by jcman; Apr 28, 2012 at 12:07 PM.
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hmm...ok I'll take another look. Looks like the image is missing from that pdf.
This line that I broke definitely doesn't connect to anything at the front of the manifold. , it goes to the back near the throttle body.
This line that I broke definitely doesn't connect to anything at the front of the manifold. , it goes to the back near the throttle body.
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From: NE Ohio
Where does it start and end?
Here is the PDF
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Thread Starter
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Yeah that pdf is better 
It looks like the line in question is the line that connects the vacuum reservoir to the intake manifold tuning valve.
I have hooked up the fuel pipe I got from Ace and gone for a short drive. Feels normal, but then the brake issue was intermittent anyway.
So what does the intake manifold tuning valve do?
It looks like the line in question is the line that connects the vacuum reservoir to the intake manifold tuning valve.
I have hooked up the fuel pipe I got from Ace and gone for a short drive. Feels normal, but then the brake issue was intermittent anyway.
So what does the intake manifold tuning valve do?
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Good to hear you found it
I noticed the driver side line running to the reservoir tank the other is for the IMT.
Your intake manifold has a air flow vectoring tube "spool" in side that runs through it front to back, it changes airflow at two points in the intake plenum runners at low and high rpm's, volume and velocity of airflow makes a big difference in a manifold.
Your intake manifold has a air flow vectoring tube "spool" in side that runs through it front to back, it changes airflow at two points in the intake plenum runners at low and high rpm's, volume and velocity of airflow makes a big difference in a manifold.
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OK well my fuel hose fix didn't last too long. It's become flattened. It may be the heat or maybe the vacuum...either way I am not sure it's a good fix.
Can you recommend anything I can use to fix this?
Can you recommend anything I can use to fix this?