Topic: 66 C4 vacuum modulator line W/PB Question

[MomsMustang66]

I have a 1966 mustang with power brakes and a C4 automatic transmission. I was needing a picture of the steel line with the rubber ends running from the power brake booster to the vacuum modulator as installed. Thanks.

[J_Speegle]

Might help if you provide where the car was built and if it is an original Thermactor car.

Don't believe we will find a hose running from the power brakes to the transmission vacuum line as we do on other years but lets see once we get more info

[jwc66k]

You should have a fitting the comes off the intake manifold to the rear of the carburetor with a curved steel pipe that transitions to a rubber hose that provides vacuum to the power brakes, and a rubber hose from a port of the same fitting that goes to the transmission. The fitting on the top picture is typical for V-8 applications, a rubber cap goes on the unused port. The lower drawing is for the I-6 application.
Jim

[Josep]

You should have a fitting the comes off the intake manifold to the rear of the carburetor with a curved steel pipe that transitions to a rubber hose that provides vacuum to the power brakes, and a rubber hose from a port of the same fitting that goes to the transmission. The fitting on the top picture is typical for V-8 applications, a rubber cap goes on the unused port. The lower drawing is for the I-6 application.
Jim

My I6 has the top picture fitting (don't know if original). I'm using one nipple for the transmission and the other nipple for the Thermactor.  Since my car hasn't power brakes, the big threaded port of the application is capped.

Josep

[MomsMustang66]

Car was built in Detroit and does not have the thermactor system.

My understanding of the vacuum connections for power brakes and automatic transmission is as follows.
1964 1/2 through 1966 cars with automatic transmission and manual brakes and one hard line with an inverted flare fitting connected to the rear of the intake manifold that went to the vacuum modulator. 1964 1/2 through 1966 cars with power brakes and a manual transmission had one hard line with an inverted flare fitting connected to the rear of the intake manifold. A rubber line then continued from the hard line to the power brake check valve. This fitting is a part number 354584-S. 1964 1/2 through early 1966 cars with both an automatic transmission and power brakes had 2 hard lines with inverted flare fittings connected to the rear of the intake manifold. One went to the vacuum modulator and the other went to the power brake booster with a rubber hose completing the connection to the power brake booster check valve. Fitting screwed in the manifold is a part number 375786-S. Later 1966 cars had one hard line with an inverted flare fitting connected to the rear of the intake manifold. A rubber hose was connected from the end of the hard line to the power brake booster check valve. This was a special power brake booster check valve with 2 hose connections. The other, 2nd connection was for the hose and hard line to the vacuum modulator. Bob Mannel mentions this in his book Mustang and Ford Small Block V8.

[markb0729]

Here's a few pictures of the fitting with the vacuum connections to the power brake booster and C4 transmission of my Dearborn Built 65 Fastback with approximate build date of September 2, 1964.

[J_Speegle]

Car was built in Detroit and does not have the thermactor system.

FYI the drawing you posted differs from 65's I have pictures but rather than discuss those, since you have a 66, I will not go into those details

Looked through my 66 pictures and don't have any nice pictures of a V8 automatic and PB at the back of the intake. Too many air cleaners in the way