Brake Booster Identification

[Kyle01041981]

I have a brake booster and master cylinder I can not identify that is on a custom street rod which my father built. I have figured out the master cylinder is possibly from a ~73 model Mustang 2. The truck has a Mustang 2 front end under it..so this sorta would make since. So i believe the booster would be ford also. However all the local parts places have struck out on helping me identify the booster.

I am attaching 3 pictures, i have a lot more pictures with measurements even including pics of the pedal assembly. Thanks in advance for any help in getting this old jewel back on the road!

[colnago]

I just did a swap to front discs on my '67 F250. Since '67 is an oddball year, I ended up using a booster for a '67, and everything else for a '68. Maybe your booster is the same. It's for your truck, and everything else is for a Mustang. I've been told that a booster doesn't care what it's boosting, and the MC doesn't care what's boosting it, so that's why I went the direction I did. Regardless of my direction, I'd say the booster for your truck is a good place to start (this assumes your pedal assembly is stock).

Joseph

[ultraranger]

The brake booster is just a force multiplier. It takes a smaller input force from the driver and amplifies the output force on the MC and then to the brakes. The booster doesn't know if you have all-wheel drums, discs front/drums rear or 4-wheel discs.

There are single diaphragm vacuum operated brake boosters and there are dual diaphragm brake boosters. Obviously, a booster with dual diaphragms will generate more output force for the same amount of input force placed on a single diaphragm unit.

MC bore size (piston diameter) has a profound influence on how the brakes will react and how much force a driver has to put on the brake pedal to get the vehicle to stop. Smaller bore diameter MCs will have greater output pressure (for a given amount of input force) than a larger MC bore. However, a smaller bore will displace less fluid volume and will have a longer pedal travel.

Larger bore MCs will move more fluid but will produce less output pressure. Larger bore MCs tend to have less forward movement of the brake pedal and can be difficult to apply enough force on the brake pedal to get the vehicle to stop within a reasonable distance.

MC bore sizing is a compromise between driver comfort in being able to comfortably apply pressure on the brake pedal vs. getting the vehicle to stop within a reasonable distance.

Drums are self-energizing, discs aren't. Drums don't require as much assist as discs and I can tell you from my own experience that all-wheel drums with a 1.00" bore MC and a powerful dual diaphram booster is not a good combination --it makes for VERY sensitive brakes.

A few years ago, I pitched the front drums on my '69 F100 and installed front discs/suspension from a '77 F100. I had already installed a dual diaphragm booster from a '75 F350 when I still had 4-wheel drums. I removed the conventional style cast iron 1.00" bore MC from the booster and installed a 'modern' 1-1/16" bore MC for a '95 Ford Explorer. This was a perfect combination and my brakes have worked exceedingly well ever since I made these changes to my truck.