I have an under 8500 1986 F250. Can I upgrade the Master Cylinder to the over 8500 one for better braking???

 

Years ago my friend had a 82 F150 we put a larger F350 MasterCylinder on it(we had it on hand) Only thing it did was make the brakes very touchy and more of a issue than worth(shattered a pad on front due to higher brake pressures). After getting the correct MC and new pads it's all fine.

Bigger is better, but not in this case unless you switch out the entire braking system to the larger one.

 

The braking force is related to the diameter of the master cylinder piston versus the diameters of the pistons in the wheel cylinders and the calipers. There is a ratio there that like was mentioned in the previous post, can get messed up if you do the wrong thing.

 

I WILL JUST GO OEM