MK4 ALH Vacuum line replacement question

Hey guys, I have some 3mm and 5mm vacuum line that I purchased from a vendor on here and would like to replace them tonight.

I did find a vacuum diagram:
http://farm5.static.flickr.com/4098/4876831739_90f557c739_b.jpg

But I am not certain where I am supposed to run the 3mm line? I am guessing where I don't run the 3mm line, that is where the 5mm hose goes.

I didn't purchase the injector return line, not sure if it's really needed.

The "easy" way to replace the hose is to do it one piece at a time: remove a hose, use it to measure the length of the replacement piece (adding a tiny bit, just for good luck), putting it in place, and proceeding to the next. That way you won't cross any paths...

Oh, and do verify the operation of the one-way checkvalve while you're at it... they tend to stop working at inappropriate times... (if you do need a replacement and can't find a cheap VW unit, Parts Source can order you (one day delivery) one meant for a Ford... [FONT=&quot] BWD EC601... About $8.50


Yuri
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Injector return line is needed if you notice wetness around the injector return line nipples or diesel dripping from the line anywhere. Otherwise, not.

The thicker vacuum line is noticeably so, you shouldn't have trouble telling the difference in the car. Just start replacing a line at a time so that the connections don't get mixed up, and you should be just fine even without a diagram. The new lines will look nice and clean (or may be a new color if you're using colored silicone, for example) so you shouldn't have trouble replacing the same line twice.

Just be careful and patient, and you'll be fine. Careful: because the lines sometimes stick to the nipples and will break them if you just pull hard enough. Better to carefully cut the old vacuum line and carefully peel it off the nipple. A single edge razor blade or a new utility knife blade will do very nicely.

Cheers,

PH

Well I replaced the vacuum lines tonight. Took a bit especially how some of the lines were routed by the firewall but got them all replaced without breaking anything

Had my gf take the car for a ride, she said it's a huge difference. I have yet to go

ymz said:

Oh, and do verify the operation of the one-way checkvalve while you're at it... they tend to stop working at inappropriate times... (if you do need a replacement and can't find a cheap VW unit, Parts Source can order you (one day delivery) one meant for a Ford... [FONT=&quot] BWD EC601... About $8.50


Yuri
[/FONT]

Click to expand...

Sorry for this but how do I check the one-way checkvalve? I am guessing blowing through it both ways would deem it bad?

Yes... either that, or applying a vacuum... you may wish to use a MityVac rather than inhaling some of whatever may be inside the unit...

Yuri

Is there a general rule of thumb of the length of line needed to replace everything in the car? Do I need 5 feet of 3mm and 6 feet of 5mm or something line that? I have a good local place around the corner that deals with hoses and line like that and could net a good deal.

Celco said:

Is there a general rule of thumb of the length of line needed to replace everything in the car? Do I need 5 feet of 3mm and 6 feet of 5mm or something line that? I have a good local place around the corner that deals with hoses and line like that and could net a good deal.

Click to expand...

On ID parts website it says 3 meters of 3mm hose and 2 meters of 5mm hose for ALH cars

Hey guys, my Injector return line seems to be in rough condition. I was thinking of replacing it but not sure on how to go about doing so.

Is it as easy as pulling the line off and putting on a new hose that is cut to the exact length?

mrrhtuner said:

Hey guys, my Injector return line seems to be in rough condition. I was thinking of replacing it but not sure on how to go about doing so.

Is it as easy as pulling the line off and putting on a new hose that is cut to the exact length?

Click to expand...

Yes, there is no special procedure per se, just pull the old lines off, and cut new lines to match, pushing them on. Don't use vacuum line in place of fuel line of course. The barbs seem to be made of brass on the injectors and pump fitting - you can still break them with enough force, though. Be especially careful around cylinder # 3's injector sensor wire, try not to disturb it, as the wires can get brittle with age. You "may" lose pump prime, in which case you just have to bleed the air from the injection system, similar to any other injection work.

What is the minimum recommended thickness of the vacuum lines? Is 1.6 mm (1/16 inch) wall/thickness OK if it's a good quality silicone hose?

http://www.newageindustries.com/datasheet.asp?PN=2800546&FAM=Tubing

amit9 said:

What is the minimum recommended thickness of the vacuum lines? Is 1.6 mm (1/16 inch) wall/thickness OK if it's a good quality silicone hose?
http://www.newageindustries.com/datasheet.asp?PN=2800546&FAM=Tubing

Click to expand...

The suitable silicon replacement hoses I've seen and used
have had much thicker walls than that. At least 3-4 mm.

ymz said:

The "easy" way to replace the hose is to do it one piece at a time: remove a hose, use it to measure the length of the replacement piece (adding a tiny bit, just for good luck), putting it in place, and proceeding to the next. That way you won't cross any paths...

Click to expand...

That's how I did it. It's tedious, but fool-proof. I also put heat-shrink tubing on the ends, to keep the cloth braid from fraying.