Type 4 engine 1972 cold warm air flap vacuum diaphragm

[lee griffiths]

Hi,

Looking for this part to make my bus stock and make use of the warm air flap mechanism. Searching across the internet doesn't come up with anything at all!

021129630 021-129-630

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Lee Griffiths
72 Westfalia Campmobile Type 4 1700

[lee griffiths]

Found it is also on Type 181 air box as well
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Lee Griffiths
72 Westfalia Campmobile Type 4 1700

[SGKent]

Would love to make suggestions and help but not a clue since you don't list your year in your avatar or signature line.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[lee griffiths]

Hi,

Thanks, as in the thread title it's for a Type 4 engine 1972 with the part number references. I've found similar looking arrangements across the range of models but cannot find the vacuum canister available anywhere, or much discussed really. It's a useful feature in cold climates and so I'd like to get it working.
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Lee Griffiths
72 Westfalia Campmobile Type 4 1700

[lee griffiths]

It's the vacuum canistor off the 72 type air cleaner

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Lee Griffiths
72 Westfalia Campmobile Type 4 1700

[SGKent]

probably it was not offered as a replacement part. There was a similar part on the later twin carb air boxes but it was NLA 30-40 years ago and deleted from the fiche. You might look for a 181 fiche or someone who has a fiche from about 1974-75 to see what the part number is and compare it. I found this 181 fiche but it does not show the part unless it is part of the whole air cleaner. There are a couple 1972 air cleaners for sale in classifieds but no idea if the canisters on them are any better than yours.

Early Bay fiche - Jersey Looker

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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[busdaddy]

Try cracking it open, some are ultrasonically welded, others just snap together like fancy Tupperware, my first try on the all plastic ones is squishing it sideways in a vise, the distortion usually pops the seam.

The diaphragm may be repairable with RTV, in some cases it's the side seam letting go that causes the leak, either way you have nothing to lose.
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[lee griffiths]

thanks both,

Yeah my research also suggests that I'm not going to easily find one of these so time to crack it open and take a look.

I can blow on the inlet (I suppose outlet!) and it does not pass, but when I suck (yuck) it seems to pass a little but no movement on the plunger, this would suggest that it's the leaking around the plunger. If this all fails then I have another plan which is to adapt an exahust valve vacuum solenoid to fit. These are very available and will be a while. They are quite small. The original canister clamps on and so fitting this new type shoud be prett easy really, but now I might as well take a look inside the one I have.

Lee
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Lee Griffiths
72 Westfalia Campmobile Type 4 1700

[busdaddy]

That's an interesting option, a little over the top though, many semi modern cars have vacuum pods similar to the VW one on things like heater directional flaps, up under the dash they are out of the weather and fumes so they last forever, a trip to the autowrecker may be in your future. Or get on Rockauto or Amazon for something like this: https://www.amazon.ca/Dorman-604-933-Vacuum-Style-...amp;sr=8-5 , it may require some mount fiddling, but the end result works the same.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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[lee griffiths]

Sure, I agree, though the exhaust flap whole part is only £35 ! so pretty much the same as the Amazon ones you linked. These days in the UK it's really hard to find an old fashioned junk yard, they have virtually all gone and now cars are broken indoors and the parts listed on ebay - no fun anymore.
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Lee Griffiths
72 Westfalia Campmobile Type 4 1700

[SGKent]

without another one to test, that part may be designed to let a certain amount of vacuum pass so your test may be flawed. Also there has to be a temperature sensing valve somewhere because you cannot apply hot air 100% of the time. I had a Jeep CJ7 hot air pipe that opened only when cold, that opened up on a hill climb because vacuum over came the valve temperature air bleed, a engineering design flaw. It was up a long grade and it set the carb on fire. The outlet to the bleed was inside the air cleaner so it pulled vacuum backwards on the long grade in at a higher RPM. I relocated the bleed to ambient pressure outside the air cleaner and put a foam filter on it, but it cost me searching for a new carb and some manifold parts that melted too. So I cannot envision that valve opening any time there is a vacuum applied to it. The sensor may even be inside it, some kind of bimetallic strip or something. That said, I am surprised you didn't contact one of the people selling an air cleaner and ask them to test theirs. You might have been able to just buy that part off theirs and pay postage on a much smaller box.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[busdaddy]

Yeah, I was a little surprised about the prices of some of those, I guess it's par for the course when farting around with vintage tech. The Googleator came up with this outfit: https://www.oldairproducts.com/products/factory-replacement-parts/vacuum-parts , no bargains there either, but they look much closer to the part on your bus.

That unit should hold a vacuum, the bleeding is done by the thermo valve that controls it, luckily those are still available (and not an arm and a leg), although the OG ones are often repairable too.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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[SGKent]

[lee griffiths]

Thank yeah I've studied the system operation and I still have the valve in the air box - not sure it works exactly right but as you say they are still available.

The operation is fairly simple, when cold the therm "switch" allows vacuum to operate the cannister which pulls up a flap in the 72 only air box "pizza" section on the right hand carb. Pulling up the flap closes abmient air intake and pulls it from a duct that goes round the back of the rear tinware to take air from cylinder numper 1. As this air warms it will close the thermo switch allowing the diapragm to release and cooler air is then used - I wonder how it maintains this state since cool air is then going through the thermo switch...

One thing I cannot find though is where the vacuum comes from. i.e. the input to one side of the thermo switch. The "output" goes to the vacuum canister we are talking about here, but I cannot see, on the 72 only set up where it gets the vacuum from.

The only diagram I can find is this which shows the brown pipe going from the switch to possibly the balance pipe elbow - though I cannot find a better diagram or photo of the actual setup. I've had a good lock around and cannot see a vacuum take-off anywhere near here... it really just needs manifold vacuum.

It's not a deal break not to solve all of this, but my bus is very stock, and it's cold here, and it would just be nice to get it all working as it should be... I mean the engine didn't even have thermostat on itself so that's going to make a big diffence - just waiting for the cable to arrive to hook it all up.
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Lee Griffiths
72 Westfalia Campmobile Type 4 1700

[busdaddy]

The vaccum supply comes from the balance tube elbow, it's one of those oddball 72 only parts, if the system is apart now's the time to add a small nipple to the balance tube like 73/74's so you can use the later elbow, or a spark plug boot. https://www.thesamba.com/vw/forum/viewtopic.php?t=...p;start=20

The thermo valve is constantly trying to turn on the heat, when it gets too warm in the air cleaner it opens and lets the flap close a little, it reaches an equilibrium eventually so the intake is a constant temp. It also serves to lean the idle mixture slightly when it's warm out, that leak it creates serves two purposes.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[lee griffiths]

Thanks, that's useful. So I see the special elbow with takeoff 021129637D

At least I know where it should be now and that I'm not specifically missing an unblocked takeoff somewhere as both are the plain elbows currently.

I see these guys have them

https://www.bugcity.com/shop/shop.lasso?cid=10&...rrt116543D

My engine is currently in and running so I'd have to pull the balance pipe to add a take off. I'll see how much they'll ship one of these elbows for.
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Lee Griffiths
72 Westfalia Campmobile Type 4 1700

[lee griffiths]

And the thermostatic valve is discussed nicely here

https://www.thesamba.com/vw/forum/viewtopic.php?t=543232

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Lee Griffiths
72 Westfalia Campmobile Type 4 1700