I have looked all over the brake booster and there is no vacuum connection.
The booster has some company’s tag on it so it either was rebuilt or the wrong booster was used as a replacement.
Funny thing is, before I did the engine work the brakes were working just fine.
Any clues?
The vacuum connection is top center. See the off white colored check valve on my car? The vacuum line is big, about 11/32" ID.
Understood after watching the WCCC video on boosters… but it isn’t there.
Let’s see it.
Peter 
Yup and that is the obvious problem.
Meaning? Do I have to replace the check valve with the vacuum connection?
Meaning that your check valve is missing.
So you will have to find one (buy one), then find out where your vacuum hose is and then connect it up to your check valve.
The check valve and the hose are probably laying on the intake manifold. Put them back where they belong.
These images might help you to visually identify the brake booster check valve appearance and location, as well as the hose + tube and routing.
So you are all saying to pull that plug and replace it with a check valve?
The thing is that the booster was not touched… so how did it work beforehand?
No problem with finding a source as there is one specifically for the brakes on the FiTech.
The only way this type of booster works is with vacuum from the engine. Your brakes will always work with or without vacuum applied to the booster, however you will only have assist when it’s provided engine vacuum thus allowing the booster to assist your foot in applying the brakes.
I still don’t know how it worked perfectly before but I ordered a check valve from WCCC and I’ll give it a go.
It could not have worked perfectly without that line hooked up, Not a possibility,
When you do connect the vacuum, make sure you’re wearing a shoulder harnesse seat belt because your foot might put your nose to the steering wheel…
So I bought a check valve from WCCC and it came in the other day. When I tried to install it I found out that it was too large for the booster. I have no idea where this booster came from and realized that there had to be a check valve before the top end was rebuilt. IOW I’m right back where I started. Do I try and figure out what booster is actually in the car or replace the booster. UGH.
Looking at the images on the WCCC web-site for the two styles of brake booster valves ( Midland-Ross and Bendix ) - it appears that the Midland-Ross ( C4AZ-2365-A ) has the larger diameter ( where it inserts into the hole in the booster unit itself ). Since you told WCCC that yours was a 1968 Cougar, they sent you the M-R version, as that was the only Booster unit available ( from the factory ) for 1968, and into the 1969 production year as well ( not sure when the changeover took place - Jan. - Feb. of 1969 ? ) - then the Bendix became the one version installed in the Cougar.
Possibly your Vacuum Booster was replaced at some point with a Bendix unit, or perhaps some generic version, which utilizes the Bendix style & dimensions of check valve.
More than likely you’ll have to obtain the Bendix check valve ( D0AZ-2365-A ) and see if that, hopefully, fits.
Best of Luck with this issue.
Agree with what GAH said but I think you probably have a rebuilt booster that came originally on a 1969 Fairlane / Comet because of the offset vacuum valve location. A Bendix booster intended for a Mustang / Cougar in 1969 would have the hole for the check valve centered behind the master cylinder.
It will likely function but not as well as the original would. And it speaks volumes on the lack of quality service you have been getting.
This is what came with the car when I bought it. Checked the address and it looks like a place out of El Monte Ca but I couldn’t figure out the phone number. A search didn’t help as it looks like the place is out of business. Thanks for the heads up on the booster.
