Vacuum Line Replacement

[JamesT5]

I want to replace as many vacuum lines in the engine bay as I can, it won't do any harm and I'm trying to get to the bottom of this boost hesitation under WOT in mainly 1st, 2nd and some times 3rd gear as well (it's starting to pi$$ me off now). There is also a high pitch 'whistle' that's a constant pitch when I hit a high RPM with WOT, it sounds like an air leak. If you've ever heard a TV making that high pitched sound now and again when it's turned on, but like 10 times louder, then that's what it sounds like. I'll try and do a video and post it up later.

Anyway, if it's an air leak I want to change as many vacuum lines as possible seeing that it's so cheap to buy (just a few quid), and I know I can just buy vacuum line from fleabay or somewhere but I'm not sure how much I'll need and what diameter. Most of the ebay stuff seems to be 4mm and I assume that vacuum lines are all standard width but some on the car seem thinner, perhaps 3mm or something I don't know.

Any advice on the stuff to buy and the cheapest place to get it is much appreciated. Thanks folks! :D

:B_thumb:

[M-R-P]

4mm and you'll need about 5M of it. The thinner pipe is the one for the recirc valve but you can use 4mm on that too.
Ebay is your friend but avoid the really cheap stuff as it's crap.

[JamesT5]

4mm and you'll need about 5M of it. The thinner pipe is the one for the recirc valve but you can use 4mm on that too.
Ebay is your friend but avoid the really cheap stuff as it's crap.

Thanks mate, what do you regard as the 'really cheap stuff'? :)

[JamesT5]

This stuff looks ok I reckon....

http://www.ebay.co.uk/itm/Classic-car-premium-4mm-Vacuum-advance-hose-1m-Lengths-vac-pipe-Powerspark-/360493656865?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item53ef18ab21

[JamesT5]

Just purchased 5m of the stuff in the link. For £15 it's hardly worth worrying about and it looks like good stuff to me.

[stribo]

I've just bought 3m for the C70, but I went for the Samco stuff, 4mm £9.99.:)

[M-R-P]

That stuff looks like what I bought for mine. Nice and sturdy.

[Shinsplintz 101]

could anyone just confirm if the 4mm hose is used on the older 850 T5 engines? thinking I might do mine. Cheers, morgan

[M-R-P]

Yes mate. :)

[JamesT5]

For £15, it doesn't matter whether it makes any difference or not, it's so cheap it's not a bad thing to replace the old lines anyway because there may be cracks and splits not easily visible.

[T5RatherAmusin]

what was in my 2.4 t5
4mm for the manifold to cbv 1 meter
7 and 8mm. from the middle of the manifold to a Tee and the the turbo intake hose. 2m of the 7mm. 1m of 8mm
then the tcv hoses 5mm- 3 meters.
I noticed that the actuator hose was 4mm but I used 5mm
so you might want extra 4mm if you want lol
then there's 10mm for the brake switch-3 meters
hth

[jdavis]

Was at a friends last week with a ~500bhp 2wd saph cosworth and he's used festo push fittings for all his vacuum lines, looks really tidy.

[LeeT5]

I can't understand why you don't just get the car 'Smoke leak detected' and stop ponsing around replacing Vacuum pipes etc that don't need replacing!?
If there's a leak, the smoke will definitely find it and probably more than one leak too!

[M-R-P]

But changing all the vac pipes would negate the need for a smoke test any way wouldn't it? And besides, his vac lines are old and crusty so it wouldn't be a bad idea to change them any way.

[stribo]

But changing all the vac pipes would negate the need for a smoke test any way wouldn't it? And besides, his vac lines are old and crusty so it wouldn't be a bad idea to change them any way.

Can't be as old and crusty as mine, I was checking them at North Weald, how they're still in one piece amazes me, but booting it through one of the tunnels on the M25 coming home, all I could hear was a loud hiss, rather than the induction and exhaust noise I wanted, so there's a leak somewhere.

[M-R-P]

Can't be as old and crusty as mine, I was checking them at North Weald, how they're still in one piece amazes me, but booting it through one of the tunnels on the M25 coming home, all I could hear was a loud hiss, rather than the induction and exhaust noise I wanted, so there's a leak somewhere.

James' car has 260k miles on it and the vac pipes have been disturbed a lot over the last 12 months.

It's not just the age of the pipes, its the environment they're subjected to that makes them brittle.

[LeeT5]

But changing all the vac pipes would negate the need for a smoke test any way wouldn't it? And besides, his vac lines are old and crusty so it wouldn't be a bad idea to change them any way.

No.

What about inlet manifold gasket, ETM gasket, split PCV pipe, blocked PCV, cracked Intercooler.....to name but a few! Changing the vac lines as a matter of cause for service is fine, but before I did all that, I'd get it smoke leak tested and then find out what else is leaking before I go pulling all my induction hoses apart just to get to them. He might need to kill two birds with one stone if there's a leak else where, but if you start by replacing just the vac lines (just in case) then that's doubling handling in my book and pointless too, no matter how old they are.
If he rips all the vac lines off and replaces them he may never find the cause.

[stribo]

No.

What about inlet manifold gasket, ETM gasket, split PCV pipe, blocked PCV, cracked Intercooler.....to name but a few! Changing the vac lines as a matter of cause for service is fine, but before I did all that, I'd get it smoke leak tested and then find out what else is leaking before I go pulling all my induction hoses apart just to get to them. He might need to kill two birds with one stone if there's a leak else where, but if you start by replacing just the vac lines (just in case) then that's doubling handling in my book and pointless too, no matter how old they are.
If he rips all the vac lines off and replaces them he may never find the cause.

Sorry for my ignorance Lee, but what exactly is a smoke test?

[silverhorse]

Sorry for my ignorance Lee, but what exactly is a smoke test?

Basically, your entire intake and vacuum system is pressurised with smoke laden air and, hey presto, smoke comes out of any leaks. I was thinking of making my own, but have not worked out how to get the smoke in.

[silverhorse]

ETM gasket,
Lee, I've reused my ETM gasket twice now and it is looking a bit mis-shaped. With what you have just said I think I will replace. Will gasket in a tube be OK?

[M-R-P]

No.

What about inlet manifold gasket, ETM gasket, split PCV pipe, blocked PCV, cracked Intercooler.....to name but a few! Changing the vac lines as a matter of cause for service is fine, but before I did all that, I'd get it smoke leak tested and then find out what else is leaking before I go pulling all my induction hoses apart just to get to them. He might need to kill two birds with one stone if there's a leak else where, but if you start by replacing just the vac lines (just in case) then that's doubling handling in my book and pointless too, no matter how old they are.
If he rips all the vac lines off and replaces them he may never find the cause.

Fair point Lee.

[JamesT5]

I can't understand why you don't just get the car 'Smoke leak detected' and stop ponsing around replacing Vacuum pipes etc that don't need replacing!?
If there's a leak, the smoke will definitely find it and probably more than one leak too!

As Martin said, plus the fact that replacing vacuum lines is so cheap there's no reason not too. It's recommended in fact that as part of a stage '0', the vacuum lines are at least thoroughly inspected and if looking a little old, changed. It's cheaper to replace the vacuum lines than it is to pay out for a test. What are you thinking man!

[JamesT5]

Basically, your entire intake and vacuum system is pressurised with smoke laden air and, hey presto, smoke comes out of any leaks. I was thinking of making my own, but have not worked out how to get the smoke in.

And there was me thinking it involved a packet of Benson and Hedges......

[JamesT5]

No.

What about inlet manifold gasket, ETM gasket, split PCV pipe, blocked PCV, cracked Intercooler.....to name but a few! Changing the vac lines as a matter of cause for service is fine, but before I did all that, I'd get it smoke leak tested and then find out what else is leaking before I go pulling all my induction hoses apart just to get to them. He might need to kill two birds with one stone if there's a leak else where, but if you start by replacing just the vac lines (just in case) then that's doubling handling in my book and pointless too, no matter how old they are.
If he rips all the vac lines off and replaces them he may never find the cause.

Let's just see what the vacuum line replacement does first before we think about filling my engine with smoke.

[LeeT5]

Lee, I've reused my ETM gasket twice now and it is looking a bit mis-shaped. With what you have just said I think I will replace. Will gasket in a tube be OK?

Absolutely not! The gasket is a 'crush' type and thus is a use once only! Just buy a new one from the dealer and don't use any instant gasket lube.


Basically, your entire intake and vacuum system is pressurised with smoke laden air and, hey presto, smoke comes out of any leaks. I was thinking of making my own, but have not worked out how to get the smoke in.

You just need to make a seal around the MAF.


Let's just see what the vacuum line replacement does first before we think about filling my engine with smoke.

It's totally harmless and not a waste of money. Takes no more than 1 hour. All dealers and most good garages have them now as they can saves hours and hours trying to look for a vac/air leak.

[dave_mito]

I made a smoke leak detector. Worked great until the smoke pellet blew a hole in the plastic tank I was using. Going to make another one at weekend I think so will get some pics up

[silverhorse]

I made a smoke leak detector. Worked great until the smoke pellet blew a hole in the plastic tank I was using. Going to make another one at weekend I think so will get some pics up

Yes please mate!!!! Make it an idiots guide so I can copy what you do!

[JamesT5]

My vacuum lines will be here on Monday, I'll be replacing as many of them as I can.

There's one other job I'm going to do as well but I'm not going to post it up here yet, I don't want to fuel anyone's ego..... :nono: :shhh: