1990 4Runner bakes are soft

A soft or spongy brake pedal is an indicator that there is air in the hydraulic line(s) of your brake system.
Improper bleeding could be a cause.
Damaged or malfunctioning master cylinder could be another cause...
Damaged, crimped, or pin hole leak in the brake line...
Leaking or damaged wheel cylinder...
Poorly adjusted brake calipers...
Using the wrong type of DOT brake fluid...
Using brake fluid from a previously opened container that has been sitting around for more than 6-months (DOT type 3 and type 4 are glycol-based fluids that absorb water).

Look inside the brake booster for fluid.. pull the vacuum hose from it and check from there .. some times brake master cylinders leak and the as where the fluid will collect.. also if h have drum brakes in rear they too could hold fluid that may not show the leak

If you removed the brake caliper from the fluid line you will need to bleed the air out of the brake fluid lines.

That is a Vacuum Problem, You need to Check the vacuum lines @ the Brake Booster, while car is running Listen for Air leak While someone Presses On Brake peddle, Either the Booster is leaking Or 1 of the lines

New to FixYa-not sure how this works.Soft brake are typically associated to a fluid/ master cylynder issue. Without viewing & knowing particulars via driving habits, mileage, etc, it is hard to duduce specific issues. Your front brakes have greater stopping pressures than the rear brakes which means they wear down quicker than the rear brakes. If you have a soft/mushy pedal, you may have worn brake pads which also leads to the brake fluid resevoir being low (shoe diminishment to increased fluid use-ratio)-you can fill the resevoir and pump up/ solidify the pedal but when you replace the pads, the fluid will overflow the resevoir.There are also indicators on brake pads that cause a high pitch squealing when the pads are low-again, without a visual or specific info like "do you hear any squealing while braking, how many miles on vehicle-the current set of brakes, do you tow anything, etc...", it is hard to diagnose; kind of like a doctor diagnosing a belly ache over the phone - there are so many factors/variables from the vagueness, it makes the situation a "guessing game"..If you can include more definitive info, it may narrow down the issue without a visual inspection. There are a lot of other components that could be the issues but the pads/low fluid will be the most common.Hope this does not cause more harm than good. G2

When you say leaking off, I assume the pedal is soft or goes to the floor when depressed. Since all of the major brake system components have been changed, the brake lines are the next suspect. DO you notice any loss of brake fluid from the reservoir? Do you see any fluid leak on the ground or at the wheels?

It sounds like master cyl. is drawing in air causing prob. also another test would bee too bleed out and get pedal back, now step on pedal and hold firmly and see if pedal creeps near floor indicating innternal leaking in master cyl. also have some one pump bakes slowly aand look for air bubbles in brake res. after bleed out indicating master cyl. is drawing air upon release of pedal.

adjust the rear beak shoes, if these need adjusting it will give a spungy pedle cos they need to travel further

You might have a leak in one of your brake lines i would look at all of the lines for a leak look at the brake drums for fluid driping out of the bottom if you dont find a leak it may be time for a brake job . a soft peddel means you have air in your system.From a leak or wore out pads or shoes or a leaking wheel cylender from wore out rear shoes . watch your master cylender to see if its low on fluid.

Don't drive it -- have it transported to a shop for repair -- it's dangerous!