“The pedal suddenly goes to the floor.”

“And it’s really scary when stopped on a hill…” Zoe says while we’re watching TV.

Nice. And she was so calm about it.

The symptom made it really easy to diagnose, but we double checked anyway. It was simple: start the truck, put my foot on the brake, and wait… There would come a point where the pedal started dropping to the floor.

Master cylinder.

Zoe picked up a stock replacement from O’Reilly’s and we had her wrench another repair on her 1987 4Runner. Putting a new master cylinder on a simple vehicle like this little truck is the perfect project for a beginner:

First, unplug the lead coming out of the master cylinder cap and then disconnect the brake lines from the old master cylinder (we used a bottle under them to catch leaking brake fluid). Find something to cover or plug them so that no contaminants get in. Zoe used some plastic wrap.

After that, simply remove the four nuts holding the master cylinder to the brake booster, and remove.

Here is the cool part: the directions for the master cylinder give you the step by step procedure on how to bench bleed it. This involves placing the new master cylinder level in a vice or other clamp on a bench, filling it full of brake fluid,  and running tubes from the fitting for the brake lines back into the reservoir. You then use a dowel to push the cylinder in and pump the air out of master cylinder.

But, I don’t have a vise or other way to hold it.

We used the truck as our “bench” by bolting the new master cylinder on to the truck without attaching the brake lines. Then, we copied the bench bleeding procedure by filling the reservoir with fluid and let some drip out. Next, we fitted the green fittings they supplied, attached the plastic hoses, and ran them back into the reservoir:

Zoe pushed the brake pedal down slowly while I held the hoses in the fluid. I had her repeat the procedure until no air bubble were present (there were a few really big ones right away, but they disappeared quickly. We didn’t even try to get all the very tiny ones out). At this point, we quickly pulled the green fitting out, put the brake lines back on, topped off the fluid, capped the reservoir, and plugged it in. Done.

It was that simple. And by “bench bleeding” the master cylinder this way, we managed to get zero air in the lines. The brake pedal feel was firm right from the start, and braking performance greatly improved. We’ll still bleed the entire system just to make sure…

Easy project and Zoe saved quite a bit of money by doing it herself.

A couple of notes though:

Buy a set of flare nut wrenches that are appropriate for your vehicle. They’ll make working on fuel and brake lines so much easier.

And! Tie back your hair. I didn’t think about it while we were doing this, but when I looked at the pics I saw it: Zoe should’ve had her hair tied up and out of the way. If this would’ve been a project on a running vehicle… yikes.

 

If you’re a Land Cruiser guy…

…don’t drive a Jeep. Don’t do it. Even if it’s a rental. Or an emergency.

The Land Cruiser Gods don’t like that.

(This is me asking for forgiveness)

You see, Natasha and I went to Charleston, SC and then Savannah, GA for vacation (and to explore places for future adventures) and our rental car ended up being a Jeep Patriot. Oh no.

Then we came back and one of the first things I do is replace the rear brake pads on the 100. It was a pain in the ass and far harder than it should’ve been. Because of that, I didn’t get the photos I wanted for a good write up.

To make up for that, here are Toyota’s instructions on how to replace the rear pads (assuming your rotors are within spec and you dont need to do any of that) from the Factory Service Manual for the 100 Series Cruiser:

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Read that. Print it. And then follow these tips:

It is hugely important that you get the piston fully depressed. I think there is a special tool to do that… On one side, I held the caliper up against the frame while Natasha pushed the piston in with the tire iron; we reversed positions on the other side. No, we didn’t have to let any brake fluid out of reservoir.

New anti-squeal shims and pad support plates are recommended. Mine didn’t hold the pads in place very well, so I held the caliper in position while Natasha fit the pads in. It took an extra set of hands, but if they would’ve  stayed up, it would’ve been a lot of easier.

Take pics, draw a sketch, do whatever you have to do to remember what pad support plate goes where. The factory manual and the instructions with the pads from Toyota aren’t very enlightening with those and they are different and go into different spots.

Buy a factory manual, paper or e-copy for whatever truck you have. They’re worth their weight…

And, if you do end up driving a Jeep, please pay your penance (get your truck out in the dirt, bathe in its gear oil, something…) before you wrench on your Toyota.