Which Brake Booster Is Right For A Classic Toyota Truck?

Toyota axle change
Image Credit: YotaTech

Do you have a classic Toyota truck? Are you installing a new axle on it? Are you looking for the right brake booster for your truck? If your answer to all three questions is yes, we may be able to help.

When you convert to another axle, you may be worried that the stock Toyota brake booster doesn’t have enough power. The brake booster is located within the vehicle’s brake system, between the brake pedal and the master cylinder. It may be physically far removed from the vehicle’s brakes. Yet, it still plays an important role in stopping the vehicle.

The stock brake booster on your classic Toyota is built to create enough vacuum to assist with operating your truck’s stock brakes. What happens when you upgrade your axle(s)? Most likely you’ve got bigger brakes on those axles. Is your stock booster still able to provide enough assist? If the stock booster is too small for your new brakes, it won’t be able to help very much.

It depends on the size of your new brakes.

Why The Size Of The Brakes Matters

The brake booster works by adding force to the master cylinder piston when you step on the brake pedal. It is sized by the manufacturer to provide the correct amount of force for the OEM brakes. But when you upgrade an to a bigger axle, you also most likely moved to bigger brakes. Bigger brakes have larger pistons, use more brake fluid, and create more pressure on the rotor.

There’s no “one-size-fits-all” answer to whether your stock brake booster and master cylinder will work. There are a couple of ways to figure this out:

  • Install the new brakes and try out the brake system. Do this at low speeds at first. Be aware that if the booster isn’t strong enough, you will have to push harder than you’re used to on the brake pedal to get the vehicle to stop.
  • Find out the size of the brake booster and master cylinder on the donor truck. If they are bigger than your stock brake booster and master cylinder, then your stock components might not get the job done. Upgrade to a brake booster that’s either the same size or bigger than the one on the donor truck.

Why The Type Of Brake System Matters Too

Brake upgrade kits

Brake boosters are more effective with disc brakes than drum brakes. If you’ve got disc brakes at all 4 wheels, your stock brake booster is more likely to work well.  If you’ve got drum brakes on the rear axle, the booster may not be strong enough. And, you may also need to think about upgrading the master cylinder.

When In Doubt, Upgrade Your Brake Booster

If you’re not sure whether your stock brake booster is up for the job, you can upgrade it anyway. Brake boosters last between 150K miles and the lifetime of your truck. If your stock brake booster is pretty old, use this opportunity to install a bigger one on your truck. The challenge is figuring out what brake booster to install. Several people have reported good results in their ’80’s Toyota mini-trucks by installing the master cylinder and brake booster from a ’90’s Toyota 4Runner. Here are couple of links for you:

’84 Pickup brake upgrade

Info on what Toyota models have better boosters

Dual diaphram booster in a ’79 pickup 

Hopefully this information points you in the right direction.