Brake / Rear end change over

[Rat Rod Bob]

I read the information about changing out my 93 rear end with an Explorer and so then getting rear disk brakes. One thing I have not seen is if you need to do anything with the master cylinder and or proportioning valve. I have also installed the front calipers from the Explorer. Thoughts would be much appreciated! Thanks

 

[don4331]

Ideally, yes - you replace the proportioning valve with the one from the Expo. The fact that I didn't, might be the reason I had so many issues with Mustang rear calipers on my Ranger.

The proportioning valve has a check valve in it to maintain some residual pressure to ensure brakes "ready" as soon as you push on the pedal.​

For drum brakes, the check valve should hold about 10 psi - enough to counter act the return springs.​

But disks don't have return springs, so they need a lot less pressure - only about 2 psi for disc brakes check valve.​

​

My thoughts based on some 20/20 hindsight.

 

[scotts90ranger]

I never changed anything on mine, has worked just fine, I agree with the above statement of "ideally" you should change the parts, I think the Explorer master has a bigger piston to deal with the bigger volume of calipers than wheel cylinders. I haven't towed or anything with mine really since I upgraded but it's much smoother operation and seems to be better braking.

 

[gaz]

Rat Rod Bob:

The original system was balanced for the size and weight of the vehicle so it may need attention in a different system.

After I swapped axles, I was concerned so I cautiously performed some braking and driving tests. My truck's overall braking "feel" improved (it was a 7.5"-3:43 for a 7.5"-4:10LS but with 10" drums vs 9"). So I left it alone.