VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1941 Vacuum Assist Shift

Got a "new" vacuum assist canister from Dens41 a while back and installed it. Was working fine for a while but has lately been giving me more and more problems - extremely difficult to shift into reverse, hard shifting into first and second. For some odd reason it seems to shift into third just fine but not "fingertip control."

Should also add that there seems to be excessive play in the column shift.

Was going to buy the adjusting tool from ChevsOfThe40s but have a couple questions first.

Does this sound like a simple adjustment problem that the adjusting tool and instructions may solve?

Second question is how necessary is the metal boot? Destroyed the old one getting it off last year and have never replaced it. Could not having the metal boot be contributing to the problem? If it is a necessary part, where do I get a new one?

I have the car fully mechanically sound now except for this one annoying thing. Even took her for a long test drive last weekend - about 100 miles round trip - and she ran flawlessly. Just have to get this shift problem fixed. Once 100% sound, it will be time to start on restoring the body and interior.

BJ,

The clam shells will not make any immediate difference in the operation. They and the boot helped keep the system free of mud and dirt, etc. On todays roads that's not near the problem it once was.

Get the adjusting tool. It is a certain size and that size is critical for proper adjustment. The instructions will tell you that when you east the control piece back and forth on the pin the piston should slide out and in. When that adjustment is reached you are done. Just hook it back up. Don't let the swivel turn whilst hooking everything back up or the adjustment may go bad again. This adjustment is real sensitive.

Order the rubber washers that go on the cylinder, CofF has them also.

Best,

Charlie

I usually take the unit off for adjusting. All you need is a suitable length of hose for vacuum.

BJ I have the adjusting tool if you want to use it you can. I may have extra metal shield for the linkage. Will have to check when we get home.

Thanks, Charlie. I kind of suspected that about the metal clam shell but figured I'd better check. I don't drive in the rain or on gravel roads so at least now I know that's not part of the problem.

Sure, Dens, let me know.

Any idea about the play in the shifter on the column? Or is that being caused by the vacuum assist being out of whack?

Have you checked for to much play where the linkage rods go in the shift arms? Since you have it drivable you want to drive up and I can take a look at it.

I was hoping you'd say that, Dens. Also looking to get your input on where/how to begin the body restoration.

I'll give you a call.

BJ,

I just completed a frame off restoration 2 years ago and would be glad to talk to you about how I handled mine. Call and leave a message if I don't answer. 989-832-7634

Good luck, Mike

Mike, I sent you an email with a picture of what I talked to you on the phone about.

Basically, it looks like I need a new lower support bushing for the column shift (or a creative work around). Unfortunately, I don't see any listed on ChevsOfThe40s or The Filling Station.

Will be running her up to Dens41 next Saturday so he can look at it, too.

Others might reinforce whether this is the correct bushing for the transmission shifter? I have a vague memory of purchasing a bushing that was too large so maintained the screw fix until I restored my car. Then I replaced the whole shift mechanism with one from another car?? The 41 Manual (pages 211- 215) is specific about how the spring area needs to be a specific space (3/4") as well as other important adjustments. Chevrolet Shifter Bushing from Chevs of the 40's

Here is a picture of how my shifter had been repaired when its bushing slipped down, It was held in place with a short metal screw. Here is also a picture of a bushing which looks like the one in the picture you emailed me. Could this bushing be set in some kind of vulcanized rubber and the rubber deteriorate over the years to cause the bushing to come loose slipping down the shaft it is meant to align???

Anyone doing any disassembly in this area should take a lot of notes and pictures so they can maintain the exact positions of each component. My theory is most transmission shifting problems (grinding of gears when shifting) originate in this area???

Hopefully, others will comment. This is a critical area for maintaining smooth shifting of our transmissions...

Good Luck, Mike

Yep, it's that danged little piece of metal in your second picture that's causing problems. It has slipped down under the spring where you would be able to see it in your first picture (the same as in the picture I sent you). When it's down there I can rock the lower U-bolt back and forth a lot, and the piece catches on the bottom of the lower support bushing when I pull the column shift forward. Actually, it's so worn out that even when I push it back up into the bottom of the bushing, the shift column still rocks back and forth, just not as much.

Makes it really annoying when trying to shift from second or third back into first while sitting at a stop sign or stop light, or just trying to shift into reverse. I wouldn't be surprised if the sloppiness caused by its slippage also effects how well the vacuum assist works.

Thanks for the link to Chevs of the 40s! I could not find that part anywhere - probably because it's a replacement nylon bushing and looks nothing like the original.