Replacing Vacuum Lines on Mk4?

Bhavick · Jul 16, 2018

Hi,

I've got a MK4 1.9TDI 2002 with an ATD engine and i think i've got a vacuum leak somewhere in the engine and i want to replace all the vacuum lines. I do have a couple of questions though. Is it better to use silicone or braided vacuum lines? What inner diameter do the replacement vacuum lines need to be and what length hoses will i need to do the entire engine? Am assuming all the lines are the same size or are they different?

KrashDH · Jul 16, 2018

Just use this kit from IDparts:

https://www.idparts.com/vacuum-hose-kit-a4-alh-p-5660.html

Lines are all quality. I just replaced all mine from this kit and it was plenty to do all of them with some leftover on the smaller line.

I would inspect your pump to brake booster line as well for cracks and replace that if necessary, with a new brake booster grommet

Bhavick · Jul 16, 2018

I have an ATD engine and this kit is for a ALH engine? See this is what i was concerned about, on idparts it says 3 meters of 3mm of vacuum hose and 1 meter of 5mm vacuum hose. How will i know which hoses go where or will i be able to tell by the size difference between the two? To be honest i was thinking of going with this:

https://www.ebay.co.uk/itm/4mm-Sili...894&_sacat=0&_nkw=vacuum+hose&_from=R40&rt=nc

BobnOH · Jul 16, 2018

Use silicon, it even comes in colors. Factory hose is 3.5mm & 4or5(?). We use 3 & 5.

from memory, please check-
3m 3mm firm
1m 5mm medium
1m 3mm Viton (for inj. return)

BobnOH · Jul 16, 2018

Bhavick said:
I have an ATD engine and this kit is for a ALH engine? See this is what i was concerned about, on idparts it says 3 meters of 3mm of vacuum hose and 1 meter of 5mm vacuum hose. How will i know which hoses go where or will i be able to tell by the size difference between the two? To be honest i was thinking of going with this:

https://www.ebay.co.uk/itm/4mm-Sili...894&_sacat=0&_nkw=vacuum+hose&_from=R40&rt=nc

Do them 1 at a time, you will be able to tell.

KrashDH · Jul 16, 2018

Bhavick said:
I have an ATD engine and this kit is for a ALH engine? See this is what i was concerned about, on idparts it says 3 meters of 3mm of vacuum hose and 1 meter of 5mm vacuum hose. How will i know which hoses go where or will i be able to tell by the size difference between the two?

It's super easy to tell the difference. You can take out the entire vacuum hose assembly with everything still connected in place to the check valves. Then replace each line 1 by 1. Take one off, cut the new stuff to length, install. Took me a whole 20 minutes to do the whole thing.

BobnOH said:
Use silicon, it even comes in colors. Factory hose is 3.5mm & 4or5(?). We use 3 & 5.
[/B]

3 and 5mm is OEM.

Bhavick · Jul 16, 2018

damn i just realized how much the shipping costs would be from idparts as am from the UK and it would cost way too much. I guess it's gonna have to be an eBay job.

https://www.ebay.co.uk/itm/3mm-Sili....m570.l1313.TR12.TRC2.A0.H0.Xvacuum+line.TRS0

If i was gonna order off that listing what exactly would i need to order for my ATD engine. Sorry for the newbie questions but i am very new at this and i need to get it right the first time round.

BobnOH · Jul 16, 2018

Good questions. Over here we have places like McMaster-Carr, Grangers, supply houses that have all sorts of bits like that. Try places like that instead of ebay,amazon, alibabba. Your auto parts people may also sell kits like the ID one.

jokila · Jul 16, 2018

Bhavick said:
damn i just realized how much the shipping costs would be from idparts as am from the UK and it would cost way too much. I guess it's gonna have to be an eBay job.

https://www.ebay.co.uk/itm/3mm-Sili....m570.l1313.TR12.TRC2.A0.H0.Xvacuum+line.TRS0

If i was gonna order off that listing what exactly would i need to order for my ATD engine. Sorry for the newbie questions but i am very new at this and i need to get it right the first time round.

If you want it to match the look and feel you might want to use this (5mm) and this (3.5mm) or search for cloth braided hose.

Powder Hound · Jul 17, 2018

BobnOH said:
Do them 1 at a time, you will be able to tell.

This!! ^^^

Cheers,

PH

Bhavick · Jul 17, 2018

Thanks for the replies guys it's much appreciated! When you take off the old hoses is there a specific way of taking them off? I've heard some people pry the end of the hose off with a screwdriver or even slice the end off with a razor blade. In terms of getting the new hoses on is that easy do you need to lubricate the ends before putting them on?

Mike_04GolfTDI · Jul 17, 2018

BobnOH said:
Use silicon, it even comes in colors. Factory hose is 3.5mm & 4or5(?). We use 3 & 5.

from memory, please check-
3m 3mm firm
1m 5mm medium
1m 3mm Viton (for inj. return)

He's in the UK and his car has the ATD engine, which is more like the North American BEW engine found in 2004+ models over here, but not exactly the same. So there won't be injector return lines, for example. (It's a Pumpe Duse engine).

KrashDH · Jul 17, 2018

Bhavick said:
Thanks for the replies guys it's much appreciated! When you take off the old hoses is there a specific way of taking them off? I've heard some people pry the end of the hose off with a screwdriver or even slice the end off with a razor blade. In terms of getting the new hoses on is that easy do you need to lubricate the ends before putting them on?

It really depends on the condition of the hoses, but the failsafe way to do it is with a razor blade. Don't actually slice the end OFF, but slice it in-line with the fitting it's attached to. The hose then should peel right off the barb.

Really no need to lubricate the ends to get them on but you could use a bit of lube if you want to. Once they're on there, you're really not ever taking them off again unless something in the system fails. I just used a little extra line per section so if I had to go that route I could cut and re-use the line if it wasn't past it's useful life.

Bhavick · Jul 17, 2018

Yes i will slice in line with the fitting that's for sure! I don't wanna break anything just want to replace the lines. One last thing someone else has recommend that i put small cable ties at the end of each hose once they are on but my original hoses don't have any. Would anyone recommend doing this as the new hoses i am going to use are silicone?

flee · Jul 17, 2018

Cable ties should not be necessary if you use the correct hose.
Silicone hoses are particularly good at self-sealing.

KrashDH · Jul 17, 2018

Yeah I used the IDparts kit and I didn't use anything on the ends either, they're on there really good...so good in fact after I installed them, I was trying to get the new one I installed off the reservoir for some more troubleshooting and ended up snapping the nipple off of it.

Bhavick · Jul 17, 2018

Thanks all for your help guys, right time to get the hoses changed!

Rob Mayercik · Jul 17, 2018

flee said:
Cable ties should not be necessary if you use the correct hose.
Silicone hoses are particularly good at self-sealing.

Unless it's just for showing that it's a new line, to visibly differentiate it from an old line...

jblltdi · Sep 17, 2018

I just replaced my vacuum lines and now need to do the line from vacuum pump to brake booster. Before I break anything, does the vacuum line just friction fit into the booster grommet (and pull out)? Any trick to replacing the grommet?

Thanks

KrashDH · Sep 18, 2018

jblltdi said:
I just replaced my vacuum lines and now need to do the line from vacuum pump to brake booster. Before I break anything, does the vacuum line just friction fit into the booster grommet (and pull out)? Any trick to replacing the grommet?
Thanks

Yes it's just in there as a press fit. A small amount of WD or something similar will help it slide out, just be sure to clean it good with IPA before you install the new one.

jblltdi · Sep 18, 2018

Thanks KrashDH.

IPA must be be something other than India Pale Ale?
And WD is WD-40?

KrashDH · Sep 18, 2018

jblltdi said:
Thanks KrashDH.
IPA must be be something other than India Pale Ale?
And WD is WD-40?

haha you could use India Pale Ale but that would be a waste if it didn't go in your face...

IPA= isopropyl alcohol
WD = WD-40...you could really use any lubricant/penetrating oil. It's just to work that connection free, and you'll clean it off after anyway

A little bit of IPA will can be used as lube when you re-insert into the grommet as well, it will evaporate after it does it's job

jblltdi · Sep 28, 2018

Thanks, that worked well to get the old line and grommet out. The new line is a very tight fit into the new grommet in the brake booster - doesn't want to go in. Should I just push harder to get it to slide in?

Is there any sort of lubricant that would be safe to use on the vacuum system?

BobnOH · Sep 28, 2018

Shove it in the freezer, heat up the booster socket might work. I believe this is all plastic fit? If it won't pop in with simple cleaning, I might use a little solvent or sand it.

KrashDH · Sep 28, 2018

jblltdi said:
Thanks, that worked well to get the old line and grommet out. The new line is a very tight fit into the new grommet in the brake booster - doesn't want to go in. Should I just push harder to get it to slide in?

Is there any sort of lubricant that would be safe to use on the vacuum system?

As I mentioned above cover the interfaces (grommet and connection) with IPA then shove it in there quick. It will provide enough lube to get it in if you work fast then it will evaporate not leaving a film behind.
A light coat of marine grease or something similar would work as well. It's not a place that gets dirty. But I mean light when I say it. Just enough to slick up the initial surface (apply to hose side, not grommet)

BobnOH · Sep 28, 2018

Liking the IPA part, surely they'll be some excess?

Replacing Vacuum Lines on Mk4?

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