[4Runner4TW]

Hey everyone, I have a 99 Runner and the power booster has failed. I picked up one from the part store for $300. I found a video online and it looks straight forward. I'm just not sure how to drain the master cylinder though. I live at an apartment complex so I need to keep the mess to minimum. Any tips on disconnecting the MC and installing it onto the new brake booster? This is all new to me so I'm just winging it a bit. I'm going to tackle the job tomorrow. Luckily I found a way to work!

Thanks!
Chrys

[Dezert4Runner]

I did this a while back with a used one that I got from a salvage yard for $80 and they pulled it for me too. Came off a Tacoma with a 3.4, so it's a universal part from what I understand. I didn't want to pay the $250+ for the auto parts store ones.

I had the luxury of not having to adjust the booster pin or whatever to the MC, and I unclipped the hard lines from the fire wall so I could squeeze the old one out and new one in without removing the MC, but I was pretty nervous about bending a hard line too much. I'm in no way, shape or form a mechanic, just mechanically inclined enough to get myself into trouble lol. Took me around 1.5 hrs start to finish, but could be done in less time. Hopefully someone can answer the MC drain question better though. Good luck.

[4Runner4TW]

That is whats making me nervous about this, taking the old MC off and putting it onto the new brake booster.

[nevada]

Originally Posted by 4Runner4TW

That is whats making me nervous about this, taking the old MC off and putting it onto the new brake booster.

just unbolt it and swing it out of the way.
leave the lines connected.

don't worry about bending the hard lines, unless you crease them, you wont hurt anything.

[4Runner4TW]

What I was hoping is I can just switch it over. I heard about bench bleeding and no nothing about it.
Also, when it comes to bleeding the breaks assuming I complete the task, Is there any bleeding from the rear brakes? I have never had drums for rear breaks and I have only bled brakes once a few years ago. Its my understanding drums work by expanding a pad inside the drum but im not sure if it uses cables or fluid or what?
Thanks for all the input! I think I might do a write up on this since I have nothing else going on this weekend.

[4Runner4TW]

Originally Posted by nevada

just unbolt it and swing it out of the way.
leave the lines connected.

don't worry about bending the hard lines, unless you crease them, you wont hurt anything.

It took me a minute to understand what you said. But it makes sense, if I am able to do this, do i need to bleed the brakes? It seems a little risky but I might be able to do it. Have you done it this way?

[HiluxSurf SSR-G]

If you disconnect any brake line, you'll need to bleed the brake system. You'll need a buddy to help you in pumping the brakes. Or you can use the motive brake bleeder.

Bleeding sequence: RH rear, LH rear, LSPV (if your truck has one), RH front, LH front

[4Runner4TW]

Im going to attempted to remove it without taking off brake lines. However if that doesnt work I did find a nice video of a 4runner on how to bleed the rear brakes. I have my girlfriend with me so she can help. I'll report back later...

[4Runner4TW]

Finished her all up. I didn't take pictures but I will go out and take a few tomorrow to help anyone in the future and write a quick write up tomorrow. Thanks everyone who helped!

[4Runner4TW]

I didn't see any write ups on this part install so I'm doing a quick one. It was fairly easy. All the pictures were taking after I installed it. Hope this helps!
Tools needed: 12mm deep socket, 14mm socket, 10mm wrench, 6in or 8in socket extension, one person to help bleed the brakes, but using a really quick technique! Also a roll of paper towels and something to place the master cylinder into that wont make a mess.

First disconnect the battery negative. If you dont the brake likes will be on the whole install. Its just safer to take off the negative when working in a area your unfamiliar with.

Next take out this pin that connects the brake pedal to the brake booster. also remove the spring. You will need these so do not lose!

[4Runner4TW]

Next, loosen the 4 nuts that hold in the brake booster. Dont take them off yet just loosen to make sure you can get to them. I used the 12mm deep socket with extension (cant remember how long it was, 6 or 8).

Note, the 4th bolt is behind the steering rack in this picture but indicated by the arrow.

[4Runner4TW]

Now time to take off the master cylinder. Its held on by 2 nuts. Use the same set up from before to take them off. What I did was take one off completely and loosen the next. I then went and took off the 2 brake lines. To help, I stuffed a ton of paper towels under it to catch the brake fluid. You wont actually loose that much. Once off, set it on its side somewhere where it wont leak. I put it in a plastic bin with paper towels. My MC reservoir went from MAX to MIN, so you dont loose that much. Also, remove the vacuum hose. I replaced mine with extra hose I had

[4Runner4TW]

To get the brake booster out you will need to move this engine hook out of the way. Its a 12mm bolt up top and a 14mm on bottom. You will have to feel for that one. Do NOT take out the 14mm bolt, just loosen it to where you can swing the hook out of the way. Same procedure when changing the spark plug back there.

[4Runner4TW]

You can now go back inside the truck and take off all 4 nuts. Then give it a light push to break it free. Go to the engine bay and pull the booster out. It will be a tight fit so be careful. There are a lot of electrical connections, vacuum hoses, and dont bend the brake lines! However, it should just slide up and out.

If you bought a refurb one like mine you might need to switch over a few parts like the piece that connects the pedal to the booster from earlier. Just count the threads and match to the new one. Its straight forward. Reinstall everything. I started with everything inside the truck (4 nuts, putting in the pin and spring) and then went outside.
In the bay, reconnect that black hook, then install the MC and brake lines.

Now time to bleed!

[4Runner4TW]

OK, this will make bleeding the brakes way easier! I got this from my buddy who is a Lexus tech. He basically told me That I didnt enter any air into the lines, any air will be at the MC. So this is what you do.
First, fill the master cylinder (MC) to the MAX line. Then crack open both brake lines and let it drip for 1-2 minutes. Just stuff paper towels under it to catch the drips.

Now tighten up the lines and get someone in the car. Starting with the line closest to the firewall, crack open the line and have the person step on the brake. Fluid and bubbles should come out. Once their foot hits the floor then you tighten the line and then they can let up.
So loosen brake line, buddy pushes on brake pedal, once hits floor they hold it, you tighten the line, they release. I did this 4 times or until there is just fluid coming out, no bubbles. Repeat for the second brake line.
This process is quick and worked amazing for me. Just watch the fluid level. Also, keep the cap off. Once done, top off the fluid level and take for test drive. My pedal has never felt better.

Edit: I did this with the truck off, Didnt even have the key in the ignition. My buddy says this is what they do when they have recalls on MC from Lexus.