LagondaNet

[AML2008]

Hi there,

having recently seen a picture of the vacuum tubes that are located under the bonnet, I wonder which connection is correct. Number 1 or number 2.
What are the differences? It would be great if anyone yould tell.
On the pictures you can see that the tubes are connected in a different way.

https://profiles.google.com/103729928060186788773/about/edit/d#103729928060186788773/about

/Martin

[jonc]

The description of how the vacuum control works is in the Owners Handbook - the ring-bound leatherette one.

I don't have it to hand at the moment, but I don't think either picture is correct, at least for a non-emissions carb car.

I think the front solenoid valve opens to atmosphere when the accelerator is not pressed, as controlled by the switch next to the carbs. I think this is to stop the vacuum advance diaphragm from being torn apart if you take your foot off the gas at high revs. The connection closest to the side of the car (nearest) should not have a pipe on it.

The rear solenoid (left in the pictures) has a pipe connected to the output of the air pump (which should be a clear pipe) and allows positive pressure to be applied to the other side of the diaphragm when the car is in Park or Neutral, as controlled by the starter inhibit circuit. This should be the pipe nearest to the camera.

So.. my guess is that number two is closest, where probably the pipe at the bottom right should be at the top left.

Incidentally, on 13277 I found the the bottom right had a pipe connected, but it went inside the cabin to the spaghetti of pipes under the dash.. where it ended. It's not uncommon for this to be messed up..

[AML2008]

Thanks a lot, jonc.
That seems to be rather difficult.
The Workshop Manual that I have does not show any pictures concerning the vaccum control. Unfortunately I do not have an owners handbook. Do you have a picture showing it? Would be great.

Thanks, Martin

[jonc]

Hi Martin,

The book is currently 2500km from me. I will be able to get to it in a week or so.

Here is the evidence from 13379:



Jonathan

[Arnaud]

Hi Martin,

You will find the owner's Handbook right here

http://www.astonmartinlagondas.com/images/Lagonda%20Owners%20Manual.pdf

But, for me it is in the parts manual page 99 or 100 or 102 depending on your car
You will find it here

http://www.astonmartinlagondas.com/images/astonlagondapartscatalog.pdf

[jonc]

Excellent Arnaud,

Page E24 onwards in the owners manual explains connections and how to test, but the diagrams in the parts catalogue are very useful - never looked at them before..

Also Martin - your photos show that the wiring is connected the opposite way round on the second picture - the red spot side (bottom connection) should be yellow/white on the rear (B) and green on the front (A) one. This is documented in the Owners Handbook, E28. I wonder if this makes a difference though - my front one is upside down on 13379..

Jonathan

[AML2008]

Great! I will check tomorrow and will let you know.
Thanks!

Martin

[AML2008]

Hi Arnaud and Jonathan,

yesterday I changed the vaccum tubes
and the corresponding electrical cables / wiring.
The tubes and wiring were in deed incorrect.
Now the Lagonda sounds great and drives perfectly.
I am very happy.
Thanks so much for giving advice!

/Martin