brake booster vacuum line routing

[mrbell321]

While replacing my fuel line, I managed to break my brake booster vacuum hose(it was super brittle, I'm amazed it held vacuum to being with).

As I was pulling out the remnants, I noticed that the hose snaked from driver's side(LHD, where the hose connected to the hardline, which so far seems OK) over the transmission to the passenger side then back to the driver's side and then back again to the passenger side, turned sharply to go through the firewall where it makes another sharp turn to meet up w/ the central weber carb adapter(which requires another sharp turn.

I can't find any good documentation on where it's _supposed_ to be, but I'm pretty sure all of the current craziness isn't factory.
Some pictures seem to hint that it goes through the driver's side bulkhead, not the engine tin. I don't have a hole there, except for some wires. There's also no obvious place in the tin except maybe where a PO has routed the valve cover vent line.

Can anyone point me in the right direction?

Also, I do not like wire reinforced hose. Or rather, it doesn't like me. Or maybe it DOES like me so much that it insists on constantly jabbing me in the fingertips with the sharpest bits of itself for fun?
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[url=http://www.vw-mplate.com/mplate2-42413.png]Click to view image[/url]

1972 Type 2 (T2) mod. 221(1)

[KTPhil]

I was wondering this as well, since I plan to add a booster to my '69 soon.
I didn't find a diagram in the Bentley, or elsewhere. Maybe a parts book might show shapes that could hint at routing?

But photos of an actual installation would be golden!

[airschooled]

Single center-mount carbs usually have a 1/2” nipple that runs to the brake booster. In the line somewhere should be a check valve, arrow pointing towards the carb.

It’s up to you how you want to run it. Some manifolds can spin 180* allowing the hose to make a more gradual yet visible turn towards the firewall. On a ‘72, you have a few options in the tin where the hose can go through, just make sure it’s protected by a grommet.

If you want more direct feedback, we’ll need pictures.
Robbie
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[SGKent]

different years have different arrangements. Some use plastic hose the whole way and some use a rubberized hose.
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[mrbell321]

My carb has a ~1/2" nipple and there was(and will be again) a check valve in the line.

I mean, I can go take a photo of my engine bay, but it'd be a photo showing that there is no hose and no hole for said hose. I'm sure I can also get photos of not Bigfoot not in the wilderness and not the Loch Ness monster not in Loch Ness...

What'd would be useful, for me anyway, is a photo or diagram proving the existence of the mythical hose and hole.
...and that sounds way more provocative than it really is...
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[url=http://www.vw-mplate.com/mplate2-42413.png]Click to view image[/url]

1972 Type 2 (T2) mod. 221(1)

[busdaddy]

Maybe you could add the year and model of your bus to your signature line, the hole moved around over the years.
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[airschooled]

Here's your factory Type 4 shown from above, with dual carbs and a later air filter. You can see the nipple passing through the tin in the top left of this photo, which was originally a power brake connection AND balance tube for the dual carbs. The 1/2" reinforced vacuum hose attached there, before connecting to the long metal chassis pipe via check valve. On later fuel-injected Type 4 buses, they put the vacuum check valve in the engine compartment to keep it out of the elements.

This STILL doesn't help you, because you don't have factory equipment. For us to give the best advice, we need to see what you have. Maybe your tin isn't stock, or the hole is used for something else…

Robbie
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[mrbell321]

[germansupplyscott]

FYI on a '72 the nipple for the brake booster vacuum supply goes through the engine cover on the right side – even though the metal pipe in the floor is on the left. '73 & '74 have the nipple on the left. The engine photo a few posts above looks to be a '74.
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SL

[airschooled]

Correct, the '72 brake hose exits and crosses the transaxle. I confused it with the 73+ auto vacuum hose which also exists on the right side, prompting the brake hose to be relocated left. The engine shown is a '73.

Valve cover venting isn't really beneficial on a Type 4, but most folks succumb to magazine ads anyway…

https://newsite.hamheads.com/2016/12/10/type-4-crankcase-breathing-system-tests-analysis/
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[KTPhil]

Not to make this thread about me, but... I'll make it about me.

I am interested in photos of the hose/pipe routing along the body. Engine bay is self-evident, and of course the area right near the booster should be clear... but it's getting for the back to the front that I'm interested in.

If the factory route makes sense, I'll go with it. If not, I plan to run 1/2 copper line, bent to conform, maybe along a frame rail, with holes/rubber bushings/p-clamps, whatever makes sense. I'd just have short rubber hoses at each end, and never worry about a hose leaking or splitting. Anyone done this?

[SGKent]

[kreemoweet]

[KTPhil]

[SGKent]

simple fix is run a line from the front to back.

Anyone who puts dissimilar metals together and says there is no corrosion doesn't understand the science of metals.
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[skills@eurocarsplus]

[kreemoweet]

Gates makes a 12 mm ID brake booster vacuum line, but I haven't been able to find a vendor who
sells cut-to-length pieces. Rock Auto sells 50-ft rolls of it pretty cheap, maybe a good item
for a group buy. If I had my booster line to do over, I would do the entire length in something
like that Gates hose.

https://www.rockauto.com/en/moreinfo.php?pk=99895&pt=230
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[sodbuster]

"Thanks! Do you know a source of this line?
Any photos?"

Call these guys and ask. Last time I was looking they had it.

http://mesahose1.com/MHhomepage.html

[airschooled]

I've used this stuff in the past:

https://www.belmetric.com/smooth-high-pressure-oem...17438.html
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[KTPhil]

Is the under-car routing obvious? I'd like to put it in a stock location, if possible, but I've never seen photos or a diagram.