VW Automatic Register

Technical forum => Technical => Topic started by: Dave on 24 October 2013, 20:52

Title: 12mm vacuum hose
Post by: Dave on 24 October 2013, 20:52
Hi,

Just a quick question.  Does anyone know what PSI or Bar rating the three 12mm vacuum hoses need to be ?
Title: Re: 12mm vacuum hose
Post by: volkenstein on 25 October 2013, 04:07
Dave,
        Not off the top of my head, but you don't want a PRESSURE rated hose, you have to look at
internal rigidity as the one thing that causes problems is non-vaccum rated hoses collapsing.

That is why we recommend Belmetric , or BMW or Mercedes REINFORCED BRAKE BOOSTER hose.

Lee and myself and no doubt a few others have used airlines (rigid) or hydraulic hose with a rated
stiff sidewall for vacuum as well as burst pressure. the downside is they are more often than not 1/2 inch as opposed to the above 12 mm.  Parker-Hannifin has a bewildering range of imperial sized hose...
but as so many others market good qual hydraulic hose.....you'll have to let your own fingers do the walking.....down to your knuckles ;D


HTH
Volkenstein
Title: Re: 12mm vacuum hose
Post by: Dave on 25 October 2013, 19:30
I see, thanks for that.  I'll get looking and let you know what I find.
Title: Re: 12mm vacuum hose
Post by: autonewbie on 25 October 2013, 19:58
When desperate, any hose will work IF you install a spring inside its full length. The spring prevents it from collapsing. An old trick but it works very well.
Title: Re: 12mm vacuum hose
Post by: Dave on 26 October 2013, 00:00
Thanks!  :)
Title: Re: 12mm vacuum hose
Post by: 68autobug on 26 October 2013, 08:54
Quote from: autonewbie on 25 October 2013, 19:58
When desperate, any hose will work IF you install a spring inside its full length. The spring prevents it from collapsing. An old trick but it works very well.

Yes, I;ve seen all sorts of hose in photos of autostick engines, including garden hose... lol

LEE

Title: Re: 12mm vacuum hose
Post by: Dave on 29 October 2013, 22:46
Does the smaller diameter shift signal hose going to the control valve have to be vacuum rated too?
Title: Re: 12mm vacuum hose
Post by: volkenstein on 30 October 2013, 01:37
Dave,
         Braided (cloth) VW hose of 3.5mm ID is all you need, or any other small ID hose. The max vacuum it ever sees is 5 In Hg. In other words...whatever works.


HTH
Volkenstein
Title: Re: 12mm vacuum hose
Post by: Dave on 30 October 2013, 08:55
Brilliant, thanks very much.
Title: Re: 12mm vacuum hose
Post by: sb001 on 31 October 2013, 00:58
Made in Germany:

http://www.germansupply.com/home/customer/product.php?productid=17046&cat=&page=3


Made in U.S. (same style hose, a little cheaper):

http://www.germansupply.com/home/customer/product.php?productid=17946&cat=&page=3
Title: Re: 12mm vacuum hose
Post by: Dave on 31 October 2013, 18:37
Thanks sb, that looks like good stuff.
Title: Re: 12mm vacuum hose
Post by: vwman55 on 14 November 2013, 13:28
Right here:

https://www.belmetric.com/metric-hoses-wire-reinforced-hose-c-14_140.html?zenid=k24bbboojqov4ng36ol1o73kd0

RH12W - Wire Reinforced Comes per meter need about 4' to do all hoses
Title: Re: 12mm vacuum hose
Post by: Dave on 14 November 2013, 14:06
Thanks, just waiting for payday now!
Title: Re: 12mm vacuum hose
Post by: sb001 on 14 November 2013, 17:14
I'm going to have to pick up one of these too- just discovered I have a big rip in the vacuum line going from my tank under the left rear fender up to the control valve.  :P
Title: Re: 12mm vacuum hose
Post by: sb001 on 15 November 2013, 16:12
Will a tear in the vacuum hose going from the vacuum tank under the left rear fender to the autostick control valve affect the car's running in any way? Or is this vacuum path isolated to the autostick system only?

(Posted this over on the samba but no responses.)
Title: Re: 12mm vacuum hose
Post by: gmurtic on 15 November 2013, 17:35
It will
The engine will draw fresh air directly into intake manifold and make the engine work bad or most likely not be able to run.
Title: Re: 12mm vacuum hose
Post by: sb001 on 15 November 2013, 19:26
Not the hose coming off the intake manifold over to the control valve; the one going from the vacuum tank under the fender to the control valve. It would still affect it?
My car has no problem running right now even with this tear, except for a bit of a cold startup issue where it idles low and "chugs" until fully warmed up-- this is the main reason I was asking. But after warmed up it runs fine.
Title: Re: 12mm vacuum hose to be REPLACED..
Post by: 68autobug on 17 November 2013, 22:27
Hi
Naturally it will affect Your car. All the vacuum hoses need to be leak free for the system to work. I would think that You probably have no vacuum left in the vacuum tank, and that You are using the vacuum coming direct from the inlet manifold..   You need to replace ALL the vacuum hoses otherwise You cannot adjust or fix anything else when problems arise.
The cotton covered hose hides cracks and its live span is over. You can replace the hose with an identical hose made by Belmetrix in the USA or from a Mercedes Benz dealership..  or a good quality transmission hose
like "gates" brand..     I have been using a USA truck  air hose  called POWAFLEX 12.7mm multi=purpose... also another one called TOTALFLEX MULTI non conductive 12mm 1/2" 1200psi BP made in USA.  I bought both these from truck parts shops.. they are a redish orange color..  and not expensive.. even here in Australia..
I believe they are used with air brakes in trucks/trailers.
the length of the hoses are: 240mm - 400mm- 620mm and I recommend replacing them all for many years of trouble free driving.

cheers

Lee in Australia



Title: Re: 12mm vacuum hose
Post by: sb001 on 18 November 2013, 03:48
Thanks Lee-- I will look into replacing those hoses with the brand you mentioned--
The thing is I must somehow still have vacuum, when I pulled that hose off the control valve there was a distinct "whoosh" sound of air being released. Also as I mentioned the autostick shifts absolutely fine. That hose did have electric tape wrapped all around it so it may have been enough to hold vacuum in. But I'll replace them anyway. I think the reddish orange hoses would look pretty cool in the engine compartment of my red bug...  :D
Title: Re: 12mm vacuum hose
Post by: 68autobug on 18 November 2013, 15:24
Hi
well sounds like there was vacuum there...
it doesn't matter what pressure is on the hose, just look at the end to see how they are made and that the inner part is thick so it won't suck in or come off the outer part of the hose.
I actually painted some of that red hose yellow... lol
and I think one was green... lol

cheers

LEE


Title: Re: 12mm vacuum hose
Post by: sb001 on 18 November 2013, 17:23
Hi Lee,

Can you confirm that this is the hose you are referring to?:

http://www.fittingsexpress.com.au/product/PFMP

Unfortunately I can't seem to find a USA vendor selling this hose- when I do a google search most everything that comes up is out of Australia. Do you know if there are any USA outlets selling this? Thx
Title: Re: 12mm vacuum hose
Post by: 68autobug on 20 November 2013, 02:02
HI
i thought seeing it was made in the USA it would be common over there.. maybe just try a truck/trailer repair shop..
maybe the other one is available RMD1012 TOTALFLEX MULTI NON-CONDUCTIVE 12MM 1/2" 1200 PSI BP 
that hose looks like it would last forever... very good construction.
maybe they are so common in the USA they don't need a special website??    try a few truck repair shops...  it should be cheaper than the Australian prices..   best of luck..

Lee in Australia