Bleed down on vacuum advance question
 

The first new vacuum advance control sent for my stock 8ba loadamatic distributor would not hold vacuum when applied by an Actron hand vacuum pump. A replacement was sent and I pump it to 15# and it slowly bleeds down to 0 in about 15 seconds. Is that acceptable?

Re: Bleed down on vacuum advance question
 

Does the pump itself hold a vacuum for a longer time if its end is plugged?

Re: Bleed down on vacuum advance question
 

Re: Bleed down on vacuum advance question
 

Yes, the pump is new and will hold. I don't know from experience, but am thinking the large diaphragm and crimped construction, maybe that's just the way it is. Then again, making an airtight seal isn't rocket science. I will try a different pump connection. Something tells me that not too many of the carb to advance tubing connections are completely air tight.

Re: Bleed down on vacuum advance question
 

A good one won’t bleed down

Re: Bleed down on vacuum advance question
 

My old rusty dented stocker doesn't beed down. Tim

Re: Bleed down on vacuum advance question
 

Keep in mind that diaphragm only works with about a 6" max vacuum level from the loadomatic, so try testing at a lower value.

Re: Bleed down on vacuum advance question
 

Good point. I have 3 Made in china from a popular 49-51 mail order place and they all leak down regardless of the vacuum applied. Finally got smart and ordered one from a local napa. Echlin made in Mexico. The website said it would not fit my '50, but it looked identical. Put the vacuum pump on it at the store counter, low and behold, it held rock steady at 6 lbs. There is a slight difference. I needed to drill a tiny hole in the arm in a different location for the retaining clip. It's in and all is good. For any 49-51 guys out there, I suggest getting the Napa ECH VC915. PS, I also checked the vacuum at the carb fitting and it varies from 2-6# as it should depending on rpm's.

Re: Bleed down on vacuum advance question
 

https://www.fordbarn.com/forum/attac...1&d=1699763641

https://www.fordbarn.com/forum/attac...2&d=1699763651

https://www.fordbarn.com/forum/attac...3&d=1699763665

Re: Bleed down on vacuum advance question
 

Good to know, thanks.

Re: Bleed down on vacuum advance question
 

Look at all the helpful info in JoeB’s post. Info that everyone else would have to learn the hard way. Now they don’t have to.
This is what makes these Internet forums so great to have.

Re: Bleed down on vacuum advance question
 

With the vacuum control on the distributor and the vacuum line disconnected, I advance the point plate by hand, then put my finger over the vacuum connection and the release the point plate and if the plate does not fully go back, the diaphragm is good. If the plate goes back to zero, then the diaphragm has a leak.