1966 M35 PG Transmission

[Tim T.]

My questions is about the vacuum pipe(s) on a 66. My vacuum pipe, at some point was replaced by BUBBA with a length of rubber vacuum hose. SWEET(lol) I am finding confusing repro pipe info for 66. Repro line is 1 pc. I think 66 only had a 2pc unit from modulator to carb. Anybody have info on these 66 M35 equipped cars? Thanks,Tim

[Ronald L.]

Re: 1966 M35 PG Transmission

What is shown in the AIM?

[Tim T.]

Re: 1966 M35 PG Transmission

HI Ron,
Here goes, my AIM lists a 2 pc unit #3895786 in diagram. A GM parts book i have lists another #3937972 as for 66-67 1 pc unit. Another transmission parts only business i found on web has a 1 pc unit claiming to be a repro of #3890546. Again I would think the AIM is the correct one. i've searched all over the web,major vendors, hobbyists, Driveline, no luck finding one.

[Joe L.]

Re: 1966 M35 PG Transmission

HI Ron,
Here goes, my AIM lists a 2 pc unit #3895786 in diagram. A GM parts book i have lists another #3937972 as for 66-67 1 pc unit. Another transmission parts only business i found on web has a 1 pc unit claiming to be a repro of #3890546. Again I would think the AIM is the correct one. i've searched all over the web,major vendors, hobbyists, Driveline, no luck finding one.

Tim------


The 1966 Powerglide modulator pipe was a 2 piece arrangement. The short carburetor end line for small block was GM #3890546 and GM #3895707 for L-36, The long line was GM #3895786 for both. I cannot find that ANY of these lines were EVER available in SERVICE. The usual GM instructions of the day for this kind of part was to field fabricate from stock. Most fuel lines were that way, too.

I do find that the GM #3937972 is shown in some P&A catalogs for 1966-67. However, the 1967 pipe configuration was 1 piece and otherwise completely different than 1966 so I don't see how a 1967 part would work for a 1966. In addition, GM #3937972 was not the original part number for 1967's, either.

[Tim T.]

Re: 1966 M35 PG Transmission

HI Joe,
Man I was hoping you would chime in on this. Thanks so much for adding some clarity for me. LIC made a 2pc repro for 66 now discontinued. Previous talks with them confirm that 66 and 67 were not interchangeable. If anyone knows a source for an original one or a LIC repro set PLEASE PM me.

[Richard M.]

Re: 1966 M35 PG Transmission

What is shown in the AIM?

Just for future reference..... Rich

1966 M35 A8

1966_M35_A8.jpg

1967 M35 A8

1967_M35_A8.jpg

[Tim T.]

Re: 1966 M35 PG Transmission

Thanks Rich. I only had a partial shot out of AIM. This is a good reference for sure.

[Ronald L.]

Re: 1966 M35 PG Transmission

Tim,
We have clarity now from the forum help.

Did you talk to LIC?
What did they say?

I took one of these (66 automatic) apart that was going restomod, do not recall if those lines were intact, the AC system still had functioning freon inside a one-owner rust-belt "barn-find", will have to see where that powerglide went...

[Richard M.]

Re: 1966 M35 PG Transmission

Thanks Rich. I only had a partial shot out of AIM. This is a good reference for sure.

Your welcome Tim. I recall similar issues on our 63 coupe M35. On that one it's also a 2 piece pipe but the forward one has a special inverted flare that connects to the front of the AFB carb.

In your 66, you'd probably be better off trying to fab your own 2 lines. You don't need a flaring tool as the ends connect to the MV and PCV with a short hose. However, the pipe ends ideally need a small bubble to help capture and retain the hose. I've made those myself using a Bubble Flaring tool, but you could probably just use a regular flaring tool to put a small flare at the ends to help retain the hoses.

Or maybe just a little dab of Permatex #2 on the pipe before you install the hoses.

The 63 had that inverted flare at the carb but I had the tools to work on it. The rear line had a special end with the Tee for the VAC on the distributor. Fortunately that line was ok.

PB290017.jpg

1963 AIM scans for future reference....

1963 Sec M35 Sheet 4. Note it doesn't show the forward line to the carb. See below.
1963_M35_Sh4.jpg

Base Eng vacuum pipe used on all applications including M35
1963_Sec6_ShB3.jpg

[Richard G.]

Re: 1966 M35 PG Transmission

As an alternative to the bubble flair:

Take a compression fitting and tighten it onto the tubing.
Remove the cap, by sliding it off. (if possible)
This leaves just the ferrule on the tubing.

Ferrule.JPG
If I can't slide them off, I cut them off with a Dremel tool.
The resulting bubble is almost impossible to tell from original under the hose.
Typically I purchase the tubing couplers so I get two per fitting.

Another option is using a double flair tool to make the bubble flair.
I have never attempted this but I am attaching a YouTube link.

https://www.youtube.com/watch?v=HVbHk0kkX8k

Best of luck.
Rick

[Tim T.]

[Ronald L.]

Re: 1966 M35 PG Transmission

I am sure this isn't exactly a high volume part...one year only... and a lesser desiered option.

What did they get for them when they were available?