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1.8t 20v inlet manifold vacuum hose

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Hi,

When I bought my car (5 door with a 1.8t 20v) one of the things the seller mentioned was a hose that went into the brake servo. It runs from the end of the inlet manifold and then into a hole on the brake servo and he said if it comes out the car goes lumpy so you may want to seal it.

So, today I sealed it up with a bit of blue tack and it made the cars idle drop dramatically and it didn't sound like it was running as nicely. Is this definitely where the pipe should go? And is it best to have it sealed or just in but not sealed? Will having it sealed cause any damage?



Any advice would be great. Thank you!

'82 c formel e - 1.8t 20v 

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Anybody got any info on this? Someone who has done a 1.8T conversion must have some idea
Thanks

'82 c formel e - 1.8t 20v 

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Yes that is correct mate it goes from end of inlet manifold to hole in brake servo. Has pipe still got the check valve on it?

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I don't think there was anything. I think it was just a bit of pipe. What should it look like with a check valve in and why does it need one? Does the pipe have to be sealed into the brake servo?

Last edit: by mortlock7


'82 c formel e - 1.8t 20v 

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mortlock7 said

I don't think there was anything. I think it was just a bit of pipe. What should it look like with a check valve in and why does it need one? Does the pipe have to be sealed into the brake servo?

The check valve is a one way valve i believe which is circular and needs to be in the pipe between the inlet manifold and the servo. I don't think I have got a pic of mine and am not with the car at the moment :(

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Do you think that's why the revs drop and the idle goes poor when I seal the pipe into the servo? I know the check valves are only cheap but am wondering whether it's that essential. No worries about a picture. Thanks

'82 c formel e - 1.8t 20v 

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Yeah I believe they are essential matey. :)

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If that goes from the inlet manifold to the servo then it should be sealed, its what makes the servo work, the vacuum in the inlet manifold.   Now if you are running a turbo then you are pressurising the servo.   I have no idea if it would hurt the servo but it certainly isn't used to being pressurised in its original guise,  so a one way valve sounds like a good idea.

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Thanks for the help guys, that makes sense. However something I don't understand is if it's a one way valve, surely air is just going to go from the inlet manifold, through the valve, into the servo. Just like it would without a valve. How do I know what release pressure I need the check valve to be? Is the problem I had when I sealed it in because the pressure is running back from the servo into the inlet manifold?

Last edit: by mortlock7


'82 c formel e - 1.8t 20v 

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The one way valve is to stop air from the inlet manifold going into the servo, there should be no air  from the servo going into the manifold, its just a vacuum that makes the servo do what it does. As I said before I don't know if running without the valve could damage the servo and maybe make it leak so it is letting air in. Do your brakes work well.

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It's not worth the risk IMO mate for the price and size of them. Get one sorted :)

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So the valve goes with the flow going from servo to inlet manifold? Therefore meaning air can't go from the inlet manifold to servo?
The brakes are okay, feel very wooden (race car ish) but not as good as I think they should be now I think about it

'82 c formel e - 1.8t 20v 

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As I am at uni I can't look at the pipe myself so got my dad to look at it. He sent photos and there was a valve in line of the pipe, the arrow points towards the inlet manifold. Therefore it's pointing the right way so why did it run poorly when I sealed the pipe into the servo? :/ could the valve just generally be blocked so air flow is restricted?
Thanks

Last edit: by mortlock7


'82 c formel e - 1.8t 20v 

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Any info? Thanks

'82 c formel e - 1.8t 20v 

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I think mine has an arrow in with "engine" on it so you know which way round to put it in. Get your old man to have another look at it.

:)

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Yes this had 'engine' on it and the valve was pointing the right way.
Should I just seal the pipe into the brake servo and just leave it like that? Will it learn to run properly after a few minutes? As I can almost guarantee this is what was causing my car to bog under acceleration, as it wasn't sealed in the vacuum it was leaking causing the air fuel mixture to be lean. Plus, it should be sealed and there should be no air leaks.
I just want to know why it didn't seem to run nicely when i sealed it in  :|

'82 c formel e - 1.8t 20v 

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I figure as this pipe has been like this for a while the engine has learnt to accommodate for this vacuum leak by increasing the fuel to keep the mixture correct.
By sealing it I am reducing the air intake so the ECU has to learn this and should after a little while run properly again? (once it has learned it does not need as much fuel, as there is now less air)
Please someone say if this sounds correct as I am going home from Uni on Tuesday night and will have a few days with the car. If this is correct I will seal the pipe into the brake servo and hopefully it will learn the new air-fuel ratio required, THENNN hopefully the engine won't lean out under acceleration causing it to hesitate!  :thumbs:

'82 c formel e - 1.8t 20v 

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SOunds good to me mate. The pipe should run between the manifold and the servo with the valve somewhere in between. As long as it is in the right way round you should be ok. Have you got the right connections to secure it into the servo? I didn't and it took me a while to find someone on here who had one knocking round :)

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It is in the right way round so should be a good'n :) no I don't, I'm just going to use some silicone sealant for now until I can find a proper connection. Thanks Smudger

'82 c formel e - 1.8t 20v 

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OK mate hope it works out for you.

Keep your eyes open for a proper servo connector :)
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