Leaking Carb

Peter,

This picture is from an auction currently on ebay for a 1929 DeSoto. It appears the vacuum tank is shown in this picture although it may have been by-passed in some manner. I have no idea if this is the original, but it may help in showing how these were mounted.

Mac

Good Les. I know what this is about and I am done with it. And I was done with it. And that is it - no PM.

Good picture. Of course the hoses are not part of the original set-up.

An interesting point is that you can use the vacuum tank as a small fuel cell to start and move the car around the shop while the rest the fuel system is out of service. I found this handy while working on my Templar and the Hudson. Both of them now long gone!

Have a nice day
Steve

Hi Mac and Steve,
Thanks for the photo and comment. Yes, this would be it and I still have the screw holes in the right places.
The car is currently running with the SU electric followed by a fuel filter and pressure regulator set at 0.5 psi. However, I will look out for a serviceable AutoVac and in time will fit this as otherwise the car is original.
Many thanks once again.
Regards, Peter

Peter, I am glad to see you have the car running well. I am sorry about the diversions but our members handled everything real well. Are you moving forward with your car?

Hi Paul,
Thanks and yes have moved forward having sorted carb and brakes. Now need to find some way of repairing or getting new water pump as sufficient water escapes around the spindle to stop me running the car for long enough to really assess engine.
Any ideas would be much appreciated!
Regards to all,
Peter

Peter,
Most of these early cars used a "rope" type packing to seal the pump shaft. This worked well in relatively low pressure systems and barring any excessive wear to the shaft and bearings means that your pump should be rebuildable.
There may be some info on sites such as Allpar that could help you through the process.
I haven't had a Mopar 6 pump apart since the late 50s and can't remember exactly how it was constructed.
If you decide to "wade into" this project, please take photos along the way and send them and the story to: desotoadventures@gmail.com so we can feature them in the magazine.
Geoff

Thanks Geoff....I will decide whether to wade or not when I get the pump off. All the best, Peter

Back to your fuel leak problem, I'd like to chime in. Even though your leak has stopped for now I don't recommend using the car until you get a proper operating vacuum tank on it. I've learned from experience that an electric fuel pump will not work safely on a car designed for a vacuum tank. A vacuum tank carb is designed for 0 psi, basically it's gravity fed. For whatever reason people think an electric pump is an improvement but it's nothing more than a fire hazard.

Your car probably came with a Kingston unit when built but they are less common and harder to find parts for. Stewart-Warner units are far more common. I used the gentleman linked in a prior post for a 25 Hudson with good results but if you want a nice looking unit restore the tank (take the dents out and paint) before he rebuilds it. I also used another guy for a 21 Sunbeam that sold me a restored unit that looked beautiful for not much more but I don't have his info handy right now. Autovac units are common in the UK and were used on the doubledeckers up into the 50's.

As an aside, I remember reading in the "Chrysler Story" book that Walter P. hated using the S-W units because they owned the patent and were expensive so he ordered his engineers to come up with a solution and thus was born the cam driven mechanical pump.

Tim, thank you so much for revisiting the AutoVac issue and for the safety warning, which may well save me huge grief. All the comments made are well worth having and especially the one about the double decker buses. Most of our old Routmaster double dockers have been taken out of commission, but this suggest so me that there should now be plenty of unused bus AutoVacs around in the UK. I will start looking in that direction.
Thank you very much and will keep you posted as to progress.
Peter

Hi all,
I have located a company that will supply an AutoVac for the 1929 DeSoto Raodster. However, he has different sizes. Is the original 4 1/2 inches across or 5 inches? He has the former as 8 inches tall and the latter he can supply in any height. He reckons that the former is about 8 litres.
Thanks,
Peter

Sorry, my previous email should read 3 litre NOT 8! Peter