VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 40 Vacuum assist problem

I have a 1940 Chevy business coupe which is a bear to shift. After purchasing it I found the vacuum shift mechanism is in the trunk. It appears most of it is there I think with the exception of the rubber boot and the tin shield for the front of the mechanism and rear mounting flange.
A close inspection of the shifting arms on the steering column under the hood revealed that the one arm has been cut and a piece welded in to make the arm longer I believe in an attempt to give better leverage. I cannot tell if the shifting rod itself has been altered.
I have read in the repair manual about the vacuum assist but find the information hard to understand as I am more of a visual learner and the photos leave a lot to be desired.
Does anyone have or can anyone direct me to photos of the vacuum assist installed on the transmission with pictures of linkage . I have the major task of figuring out what is original and what has been modified so I can make an attempt to repair it to its original state and function. Thanks in advance for your help.

I have the new tin shield if you need one.

Appreciate the information about the shield. Will see how many of the parts I can come up with along with how to pictures or info before I commit to the project. Have seen the mount bracket on eBay and rubber boots can be found at supply stores. Of major concern in the shift rod and modified shift arm that may be hard to find.

Look for some more shift rods in the back of the car. He may have found the "kit" that was available to replace the vacuum assist. You will need the original shift rod in addition to the vacuum unit with mounting hardware. Too bad owners removed the original vacuum shift unit as it was very helpful when installed and adjusted correctly. See repair manual.

Hi drlenn,

Chevy's of the 40's lists a reproduction Vacuum Shift Arm for sale for $40.00, as well as the tool to adjust the vacuum shifter, and the rubber boot with its rectangular grommet (see page 102-104 in their 2013 catalog or go on line to their web site https://www.chevsofthe40s.com/ ). Page 102 has some excellant diagrams.

I think you should try to post some pictures of what you have so we can better tell you what is needed. I have several used vacuum assist parts that I can sell you. If you can't post pictures let me know and I will post some of my parts, and others can tell us what is missing.

We do have an index for our chat site of all are past posts. We have discussed shifting problems a lot. Try doing a one word Advanced search of our posts. Use words like "SHIFTING" or "VACUUM" or " LINKAGE" to see what has been discussed.

As I understand it the vacuum assist system is the same in all passenger cars from 1940-1948.

You have entered the TWILIGHT ZONE when it comes to easy shifting of our old cars. Be patient and we will all try to get you to be happy shifting your 1940.

Good luck and welcome to our chat site. Your post has already attracted 2 of our best sources for information on this site, Chevgene and Ray. As the day grows longer more help will be on its way.

You may want to stock up on some extra rations. The guys might want to make a house call. Mike

I will post some pictures which should aid those who are trying to help me. I had looked at the information at the site you suggested but had not noticed the replacement shift rod which is now available. Thanks for that piece of my puzzle.

Here is what I found in the trunk. The unit is very stiff but appears to be all there I think . Will later shoot pics of what is currently installed.

From the 48 shop manual

drlenn,

Chef-chevy's diagram should be very helpful. I can sell you the bracket and boot that you are missing. They will come sandblasted and ready for paint. Let me know if you need anything else. You can send me a PM (PERSONAL Chevy Chat MESSAGE through THIS web site) or email at fraub48@yahoo.com.

Thanks, Mike