I Like Big Brakes and I Cannot Lie!!!

[cme4lyt]

So does my FJ40!

So does my 40, some of the best brakes I’ve owned....

 

[fjbj40]

When you look at the factory disc brakes from a 40 to a 60 to a 80 they have not increased much in size but the truck weight really has gone up with every generation!

 

[I Lean]

How much of a difference does it actually make?

You can see my results here, to get an idea: Big brakes for the 80
Mine is a bit different since I used 80 calipers, but the rotor diameter is the same. This one will also increase available clamping force potential as well. (which may not functionally matter since I could always lock my brakes)

 

[Dirty Koala]

Yesterday I was a little bored so I cracked open a spreadsheet to layout the data and calculations needed to determine the best Master cylinder to go with for this swap.

• The 80 Series Master Cylinder has a 25mm bore..or 0.9843"
• The T100 Master Clyinder has a 1 1/16" bore or 1.0625"
• The 80 Series Caliper Piston OD is 45.3mm or 1.7835"
• The 4Runner Caliper Piston OD is 48mm or 1.8898"

I have laid out three combinations for MC and caliper for comparison. (80 Caliper + 80 MC, 4Runner Caliper + 80 MC, 4Runner Caliper + T100 MC)

• Establishing a baseline to compare off of, you can see that the leverage ratio of the stock setup is 6.57:1.
• By changing just the caliper side to a 4Runner caliper, the new leverage ratio will be 7.37:1. This will result in more pedal throw (12.3%) to get the same amount of caliper piston travel.
• By also changing the Master Cylinder to a T100 MC, the leverage ratio becomes 6.33:1. This will result in a marginally (3.7%) shorter pedal throw than the stock configuration to get the same amount of caliper piston travel.

After doing the math, I ran over and picked up a T100 MC from @cruiseroutfit to slap in sometime later this week.

 

[Cruzilla]

You will have more pressure from the 80 master, but it will require more pedal throw. The smaller bore will increase hydraulic pressure.
I will try the 80 master first as I just installed a new master last week. My new rotors and calipers will arrive on the 30th and my hubs are at the machine shop now.
We will see how much the extra 12% pedal throw works out.

 

[Cruzilla]

Here is some more info
Toyota Brake Master Cylinder and Brake Booster Specifications
Toyota 4x4 Brake Master Cylinder and Brake Booster Specs

 

[Dirty Koala]

You will have more pressure from the 80 master, but it will require more pedal throw. The smaller bore will increase hydraulic pressure.
I will try the 80 master first as I just installed a new master last week. My new rotors and calipers will arrive on the 30th and my hubs are at the machine shop now.
We will see how much the extra 12% pedal throw works out.

Yes that is correct, I am tempted to run with just he 80 master first so I can have a proper comparison before swapping the T100 MC in.

Here is some more info
Toyota Brake Master Cylinder and Brake Booster Specifications
Toyota 4x4 Brake Master Cylinder and Brake Booster Specs

I referenced this page yesterday looking for some stats.

 

[Cruzilla]

80 caliper or MC?

 

[Dirty Koala]

80 caliper or MC?

80 Master...typo...fixed now

 

[Dirty Koala]

The T100 master cylinder has an internal float switch whereas the 80 master has a float switch in the lid. The connectors are different between the two so if you want to use a T100 master and have the low fluid condition trigger the BRAKE light in the dash you will need to make a harness.

It took a solid day of sweet google-fu skills to figure out, but the female connector and two terminal repair wires were found and are available. I ran over to see my buddy George at my local dealership and picked up the parts yesterday.

Shout out to @Onur for his housing part number list...made light work of figuring out the appropriate terminal wire splice pet numbers.

 

[Cruzilla]

Nice! my parts arrived today and my hubs should be done tomorrow. This will be a fun weekend project!

 

[JeepinPete]

Interesting. My '95 has the switch in the cap like you stated, but my '93 has a switch in the side of the reservoir like the T100. What are the odds the connection is the same?

 

[Cruzilla]

How much wider are the 4runner calipers than the 80 series calipers? I am wondering about inner wheel clearance with the bigger calipers.

To answer my own question, the 4runner calipers are about 1/8 inch narrower than the FZJ80 calipers.

 

[Cruzilla]

They may be narrower, but they sure are longer!!

 

[Dirty Koala]

Interesting. My '95 has the switch in the cap like you stated, but my '93 has a switch in the side of the reservoir like the T100. What are the odds the connection is the same?

Do you have ABS? According to a thread that Kurt posted these are the two master cylinder part numbers that apply to a 93.

(47201-60540) - 8/92-5/94 FZJ80/HDJ81 NO-ABS (4 bolt)
(47201-60550) - 8/92-1/95 FZJ80 w/ABS(4 bolt)

I found a picture of the non ABS version and it certainly looks like the same connector as in the T100. Which if that's the case, a T100 might be completely bolt in for you.

 

[cruiseroutfit]

The 34031 T100 plug is the same for 60511, 60540, 60550 & 60570 variants of the 80 Series masters. Pic from my master thread:

We should have the connector housings here (non-inventory stuff) as well as the loose crimp terminals and weatherproof grommets you can use to match wiring colors should you choose to go that route too. The 82998-12440 does have the nice weatherpack type grommets right on it so they are an easy fix too.

The 60551 used on the 1/95-1/98 FZJ80 W/ABS does have the cap type connector and you'll have to extend wiring or make a pigtail harness to connect to the factory plug. I've not tried to make a short conversion harness but if there was enough demand we could definitely find that other Yazaki cap side housing. I suspect if you were to cut the original cap wires near the cap and crimp on the new terminals and connector housing there might be enough room to connect to the side of the reservoir with factory wires?

 

[Dirty Koala]

The 34031 T100 plug is the same for 60511, 60540, 60550 & 60570 variants of the 80 Series masters. Pic from my master thread:

We should have the connector housings here (non-inventory stuff) as well as the loose crimp terminals and weatherproof grommets you can use to match wiring colors should you choose to go that route too. The 82998-12440 does have the nice weatherpack type grommets right on it so they are an easy fix too.

The 60551 used on the 1/95-1/98 FZJ80 W/ABS does have the cap type connector and you'll have to extend wiring or make a pigtail harness to connect to the factory plug. I've not tried to make a short conversion harness but if there was enough demand we could definitely find that other Yazaki cap side housing. I suspect if you were to cut the original cap wires near the cap and crimp on the new terminals and connector housing there might be enough room to connect to the side of the reservoir with factory wires?

A short conversion harness would be great so you don't have to hack into the main harness, nor piece it together like I am doing. I was thinking of cutting the wires on the cap, leaving enough room to connect to the 82998-12440 terminal wires coming out of the 90980-11207 T100 female connector. If there isn't enough length, I would just add more wire and one more connection point. The other possible solution if more length is needed, is to find the appropriate terminal wire for the cap side connector. Then re-pin the cap connector with the new longer terminal wire and solder both sides together. harness would be 320mm long at that point.

 

[Cruzilla]

I wonder if the tanks are swappable between the T-100 and 80 series masters.. may be easier than swapping plugs.

 

[Cruzilla]

Kurt, do you have the T-100 masters in stock? 1-1/6 variant?

 

[Dirty Koala]

I wonder if the tanks are swappable between the T-100 and 80 series masters.. may be easier than swapping plugs.

Possibly, I just eye-balled them and they ports do look to line up.