Rear Disc Conversion Information

Not in this case, the rear gets lower fluid pressure because the drums need less pressure to actuate than the fronts. The stock MC was not actuating the rear disc brakes at all when I tried it and the rotors rusted quickly. Replaced the rotors and the MC with one designed for a disc/disc vehicle, either tundra or sequoia, and overall stopping power is better, you can really feel the brakes where stock brakes with heavy wheels and tires were definitely overworked at times. I ended up flushing fluid frequently to keep up with overheating, particularly when I towed anything. Have not experienced anything like that since upgrade in either case, rotors rusting or brake fade.

 

I actually did end up running the calculations but didn't update this post.

Without changing anything else, going from the stock drum brakes to the 4Runner discs will have the rear brakes working almost twice as much as the drums were at the same pedal force.

Changing the master cylinder to a different size will not change the brake bias on the truck, it will just change the pedal force to braking force equally for the front and the rear. No biasing happens in the master cylinder for the Tacoma, Tundra, or Sequoia.

Based on your description, it really sounds like you may have had air in the system and/or an internal leak in your original master cylinder.

Changing out from the stock Tacoma master cylinder to one from a Tundra will increase the braking force by 34.7% with the same pedal force, but it's an additional 34.7% for both the front and the rear.

So if anything, after swapping to 4Runner rear brakes, you would want to do something to reduce the pressure to the rear brakes to keep the bias correct.

Jeff

 

I just have to lol this thread.

 

Drum brakes seem dumb but I can't argue Toyota's reasoning. They seem to do very well.

 

Recently bought a 03 xtra cab 2.7L I4, previous owner switched out the drums….. does anyone know the part number of the pads used? Trying to get my inspection done but need nee rear pads.