posted August 2019

1st Gen 4Runner (84-89) 4cyl Brake Upgrades

Note that many of the details for what fits here apply to the v6 4Runner as well, however many of the parts are already the "better" ones. The master cylinder recommended below has residual valves for the front and rear ports whereas the v6 MC only has a front port residual valve, this is really only an issue if you put disc brakes in the rear.

The Stock Setup

The 4 cylinder (22R-E) version of the first generation (1984-1989) Toyota 4Runner has a fairly weak design of it's brakes. The v6 version has some improvements over this design and the beauty of the Toyota family of vehicles is that many parts are interchangable. This means that we can take some of the design queues from the v6 model and other models and incorporate them into our 22R-E models. This is especially useful when you're running larger/heavier tires, but even a stock vehicle will benefit from these upgrades.

When I first got my 1985 4Runner, the braking system was abysmal. I knew the brakes were pretty weak, as I previously owned an 87 (which I never upgraded). But the brakes on my 85 were particularly bad. Sometimes when I would engage the brakes, the right rear tire would lock up! It turns out this was due to the wheel cylinder being blown.

It's not supposed to look like this!

Braking System Components

  • Master Cylinder - The stock master cylinder is a 13/16" bore design with a four hole flange and a cap based fluid level float sensor.
  • Power Booster - The stock booster is a single diaphragm vacuum assisted brake power booster.
  • Front Discs - The stock front discs are a solid type design as opposed to vented.
  • Front Calipers - The stock calipers are a 2x2 design, containing 2 large pistons and 2 smaller pistons.
  • Front Pads - Chances are you don't have the stock front pads anymore, however, if you upgrade the calipers and discs, you'll want to upgrade to a matching set of pads as well.
  • Rear Brakes - The rear brakes are nothing special, just a run of the mill self adjusting drum type. Note that you can upgrade the wheel cylinders to a slightly larger bore, but DO NOT do this unless you're doing the master cylinder upgrade as well.

Modifications

The most desirable combination is to use a larger 1" bore master cylinder and a dual diaphragm brake power booster. Upgrading the calipers and discs help as well. Note that the v6 4Runner parts mentioned below can come from a 1st or 2nd Gen (88-95).

Master Cylinder

A 1" bore master cylinder will push more fluid volume though the braking system. Because the size of the lines are fixed, that greater volume means more pressure from the same system. More pressure, means more braking force. There are essentially two master cylinders to choose from, a Landcruiser version and the v6 4Runner version. The FJ80 Landcruiser version(paid link) features dual residual valves (front and rear) and is a superior unit while the v6 4Runner version has a single residual valve for the front brakes only. A master cylinder should be bought NEW only. The FJ80 MC has a different fluid level sensor plug, you can snag a pigtail off of many mid-90s Toyotas, including a Camry and some Lexus vehicles. It will also require re-bending one of the brake lines, but that's not tough to do.

Power Booster

A dual diaphragm booster from a turbo 4 cylinder (86-87) or v6 (88-95) will work great. There are reports that a T100 booster works as well. A dual diaphragm booster provides additional vacuum boost over the single diaphragm version for a better pedal feel, especially under heavy braking. Note that on the solid axle 4Runners, there are clearance issues for ALL upgraded boosters except the VERY hard to find turbo dual diaphragm boosters because the turbo version is the same diameter as the solid axle version. Basically, you're looking for the same mounting points (4 hole flange) for the master cylinder and firewall. I found the booster for my 1985 4Runner at a local pick and pull from a 1995 v6 4Runner. I had to grind down the flange to clear the steering shaft, but it works flawlessly.

Front Discs

Vented versions of the front discs are available, my recommendation would be Brembo(paid link) for 1990-1995 4Runner. I do not recommend slotted or stippled discs for an off-road vehicle due to the propensity for rocks and mud to get stuck.

Front Calipers

The v6 version of the calipers are a 4 large piston design with larger cooling fins. The 4 larger pistons provide more squeeze to the pads to help stop the vehicle. The larger pistons require more pressure from the master cylinder, and will work in concert with the 1" bore upgrade. Calipers are specific to the Left(paid link) and Right(paid link) of the vehicle.

Front Pads

Chances are you don't have the stock front pads anymore, however, if you upgrade the calipers and discs, you'll want to upgrade to a matching set of pads as well. I chose Akebono ACT436(paid link) pads and I've been extremely happy with them. The only strange thing is that the fitment guide says 1990-1995 Toyota 4Runner and Pickup rather than the expected 1988-1995.

Rear Brakes

The rear brakes are nothing special, just a run of the mill self adjusting drum type. Note that you can upgrade the wheel cylinders to a slightly larger bore, but DO NOT do this unless you're doing the master cylinder upgrade as well.