Rear disc brake conversion on 2nd gen

Blasphemy! Good job!

 

For those adding the Sequoia master, this helped. For bending lines. Yes a 3" section of tubing.

 

I have the same rear disc setup on my '87 4runner, it has a hodge podge of toyota brake parts. T100 dual diaphragm booster, FJ80 master cylinder, Summit manual proportioning valve, Tundra 13wl front discs, and 5th gen 4runner rear discs. That thing stops amazing with 37" tires

 

to "good enough" isn't good enough.

 

I appreciate this thread even with the little drama and terseness included. I know there have been many conversations about this idea of rear discs, i have been considering it as, like many of you who travel in the rockies and out mountainous areas, With long steep grades Sometimes engine compression isn’t enough and you have to intermittently apply the brakes. I plan the 4Runner upgrade on the front, but i will also end up with an extra disc rear out of an FJ once i complete all my projects. I want to add it to my Taco, but i havent really found a solid case In my research where someone has done both upgrades with the Electronic booster the TRDOR has. Since i have all you experienced people talking here currently, whats the opinions on this, 5gen 4R front and disc rear with the electronic booster?

 

No need to adapt the Sequoia part, the late model Camry and Avalon unit is a bolt in.

https://www.tacomaworld.com/threads/23mm-master-cylinder.641175/

 

Interesting!

 

I am in the same boat. I have the kit in my garage and have the newer e booster. I chatted with a couple folks elsewhere that have the BBK version front and rear disc setup and they say they love it. Seems like some pedal softness but overall no complaints they said. Only reason I did not instal it was lack of easy master upgrade but I think with them and @Torspd im going to install it. I hit up SOS about the cost for the matching willwood caliper and bracket as I have the T4R w/ 6pot Wilwood up front now.

So for the most part T4R up front and rear is what I will have just upgrade caliper but same T4R rotor. When I bought it I had the 5th gen T4R up front but never got around to installing it.

 

So where’s the thread about one of you geniuses swapping an electric brake booster in? With the addition of A-Trac to boot?
My 07 TRD-OR doesn’t come with it

 

That sounds like the best of all worlds if you can get the e-booster dialed in correctly with discs in the rear and big brake kit up front

 

Cool upgrade. Is it necessary for the average Tacoma owner like me? Probably not. But cool nonetheless....and it seem like some time and effort went into them. Nice.

Not sure what some of the hate is though. Their trucks....their money.

 

Fkn park brake holddown spring pain in the ass. Never swear long time this much lol . And brake pads from rockauto wrong . Off to napa tommorow

 

I remember that fight well. I had one of the earlier kits. It seems easier now on the newer revised kits. Per what I heard from Lucario Runner.

 

that isnt going to be worth it or likely possible. The electric booster is ALL tied into the VSC ecu which also ties into the engine ECU and 4WD ecu. unless you swap harnesses, it wont work. You might be able to make it work with just electric boosted, but ANY traction control wont work.

 

i have been looking into if its possible to swap in a T4R E booster into the Tacomas that have the e booster/VSC with the idea that the T4R is setup for dual disc setup. Those damn things are $$$$ so won't even be a thought unless I can score one off a wrecked one for cheap. The 2010-2014 T4R looks to be compatible and is the years the front and rear T4R setups are based off of. I do not have enough data and note quite ready to try it for fun.

 

One question I was curious about in terms of braking bias. You obviously do not want too much braking in the rear and have been contemplating if/when I install my disc conversion kit (been sitting in the garage for a year due to how the electronic master will handle it) upgrading to 4 pot wilwood calipers. I have the Aero 6 up front already.

The contemplation I have is my front setup uses 338 4runner rotors paired to the wilwood calipers (slightly smaller then the BBK they offer (342mm or so). The SOS rear BBK upgrade uses 345mm rotors Will the 7mm be that much of a bias difference? I have not seen this setup yet.

I have seen at least one person running the electronic booster/vsc setup with the stoptech BBK front and rear and says its was a great upgrade for a heavy truck. If I can score a deal I am considering swapping out the OEM 4runner caliper/rotor in the rear for the larger wilwood setup. Not sure how much added bias that would cause. Anyway to estimate it?

 

If the T4R e boosted masters are in fact a different piston size, it LOOKS like you could get away with going to a junkyard, stripping the master cylinder body out of the center where the main piston is housed, and swap just that.

But you would want to confirm its actually different... unfortunately all OEM part numbers dont have just that part as its packaged with other things.

 

Found it!!
https://www.tacomaworld.com/threads/upgrading-to-a-trac-from-no-vsc.584362/

 

YEAAAAH.... thats a gnarly swap.

 

The 2003-2009 4Runner uses a 22.22 mm master cylinder for front and rear.
The 2010-2020 4Runner uses a dual-sized master cylinder, 19.05 and 26.99 mm, this is the same as the 2005-2020 Tacoma and the 2007-2014 FJ Cruiser with hydraulic booster.

NOTE: That the dual-sized masters used in the Tacoma, FJ, etc., use the large size master for all normal braking. The second diameter is used as a failsafe in case of leakage, etc., on the primary piston. It is not used to have a different rear bias.

Jeff