I have a 1977 f-150 4x4 and not sure which master cylinder I should get...I looked up autozone website and searched the 2wd vs 4wd and the part numbers are the same.. so on ebay I bought a master cylinder that said 4x2...not sure what that means ( I am still trying to learn ) and the seller is telling me it will not work on my truck because it is a 4x4 and the cylinder is for a 4x2....sooooo I looked at Dennis Carpenter website they have just "master cylinder" and on Jeff's Bronco Graveyard they have several different kinds 2wd,4wd,power,non-power, etc...Kinda hoping for a little clarity Thanks !!!

 

Welcome to FTE. The Zone can make mistakes on their web site. You have a 4x4 get a 4x4 one. "4x2" is 4 wheels, 2 wheel drive.

Do you have a black round diaphragm looking part that the m/s is bolted to? If you do, then you have power brakes, and that is the power brake booster you are looking at.

Also make sure you get a cheap Chilton or Hanes book at the parts store to explain the bench bleed process on the new m/s.

Is it calling for one of these? http://www.autozone.com/brakes-and-t...-brake-system#

 

A brake MC is nothing more than a manually-operated hydraulic pump. Some come with ports on the left side, some come with ports on the right side and they come in different bore diameters.

Some are designed for 4-wheel drums or, discs front/drums rear or, for 4-wheel discs. Some are designed for use on a brake booster and some are designed for manual brakes.

If you have power brakes, you need this one.
BrakeBest Brakes Select NMC1617 - Master Cylinder | O'Reilly Auto Parts

If you have manual brakes, you need this one.
BrakeBest Brakes Select NMC1667 - Master Cylinder | O'Reilly Auto Parts