FYI FORD MustangSteve's Ford Mustang Forum / trouble installing PB-5 kit, template issues

**Posted by assault_muffin** 10/16/2024 6:39 PM

Not sure if anyone will know the answer to this, if not I'll try and call tomorrow. I'm working on a 66 coupe.

I am installing a PB-5 kit and I am ready to drill/enlarge the holes in the firewall to fit the new pedal support and the studs on the rear of the power booster. In the instructions, it says to print out the template and verify that the width when printed is 4.625". I did that, it had to be scaled to 83%, but I printed a template and the exact size was 4.625" where indicated. However, the center hole, which is where the bellows is supposed to come through, only measures exactly 2", where the template wants it to be 2.375".  When the template is printed so that the bottom edge measures 4.625 like the instructions say, the bolt holes do not line up with the studs on the booster and the bellows hole is too small. When I tape it to the firewall I cannot get the top two bolt holes to align like the instructions say to.

Now, if I enlarge the size of the template so that the center hole is 2.375" like the template says, then the bolt holes line up with the studs, and the bellows fits like it should. But the bottom width is now 5.47" which is NOT what the directions and the template says it should be.

Anybody had this issue or know which measurement I should be using? I don't want to start cutting/drilling if I'm misunderstanding something.

Last edited by assault_muffin (10/16/2024 6:42 PM)

**Posted by BobE** 10/17/2024 7:43 AM

I think your best option is to call and find out why.
Although, I don't understand why the your computer would reduce the size to 83%. And, while it is always good to verify dimensions, it is a little surprising to me that the installation instructions would highlight this as a 'caution' step. Seems to indicate to me that this has been an issue previously.

**Posted by mustangermike** 10/17/2024 7:50 AM

That's really odd, but not surprising. When we print the template out to ship with the kits we have to make sure that the template is correct too. And that's even when we print it on our printer that we normally use. My experience, and from what I hear of other folks, is that all printers will print drawings like this differently. I don't understand why, but that's what I have found. I'm sorry for the confusion though. I would take the firewall plate, the part that you're printing a template of, and just trace it in order to assure that all the holes line up properly. That's a surefire way to guarantee that everything lines up as it should.

**Posted by Nos681** 10/17/2024 9:16 AM

The center hole for the bellows does require modification.

Definitely worth the effort…my opinion.

**Posted by MS** 10/17/2024 8:42 PM

The center hole is of no consequence when drilling the booster stud holes. With most brand new boosters, the 2” center hole works fine. Just be sure the studs fit first, then enlarge the center hole so you are certain the booster’s rubber bellows will not drag or be cut by the sides of the hole

Mustangermike’s advice to trace the mounting plate is probably best/easiest practice.