HOW-TO: 5th Gen 4Runner Brakes on an 80 (2 Viewers)

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@jcardona1 From the pics, it looks as though the inboard lower knuckle studs are no longer available for maintenance torque checks. True?
 
I'm still finalizing the last few pieces of this upgrade but wanted to share the details with folks. I've seen a few other brake upgrades that involve different rotors and a bit of machining but in my opinion this is the easiest way to get bigger brakes without the extra work. I've seen a few guys running this hub/rotor/caliper setup now for quite some time and haven't seen any reported issues. I've yet to see a detailed write-up using this configuration so that's where I come in!

Let's start by buying some stuff. You'll want to make sure you get the calipers from the earlier 5th gens (2010-2013) with 14WA stamped into the caliper. The later year models switched to a 14mm mounting bolt vs our 12mm mounting bolt. These will have 14WB stamped into the caliper. Caliper specs:

5TH GEN FRONT CALIPER (14WA stamping, For 338mm rotor (All Trims)
Toyota Part #: 47750-60300 - LH, 47730-60300 - RH
Mounting Bolt: 12mm
Piston Size: 48mm
Bleeder Size: M7 x 1.0
Inlet Size: M10 x 1.0

And here are the specs on the rotor:

5TH GEN FRONT ROTOR (For 14WA front caliper (All Trims))
Toyota Part #: 43512-60191
Outer Diameter: 338mm
Thickness: 31.8mm
Hub hole: 108mm
Bolt hole: 14.4mm

I've read of issues with sticking calipers whether new OEM and reman so I just decided to go with aftermarket to take advantage of the long warranties. For the calipers I went with new aftermarket (not reman) Raybestos units. Part numbers are FRC12551N and FRC12552N.

Here's a comparison of the stock 80 calipers and the 4Runner calipers. The 80 Series Caliper Piston OD is 45.3mm or 1.7835". The 4Runner Caliper Piston OD is 48mm or 1.8898". Credit to @Dirty Koala for providing the math and specs on these things.

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For rotors I also went with aftermarket from R1. I went with their Carbon GeoMet cross drilled and slotted version because I hate money and like flashy parts. 311mm/12.2" vs 338mm/13.3", a whole inch bigger.

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First step is figuring out the caliper mounting. Now, the 4Runner caliper will bolt up directly to the 80 knuckles no problem. But because the rotor has a deeper hat and we're not doing any machining of the hub, the rotor will sit DEEPER over the knuckle compared to the 80 rotor. This then means the caliper needs to be spaced BACK. Based on what I heard from other that have done this, the caliper needs to be spaced back about 10mm.

On the FB 80 page someone found these machined spacers that looked to do the trick. They have an ID of 12.09mm (perfect for the mounting bolt) and are 9.52mm thick.

Here's the link: 12 mm ID 316 stainless washers spacers - https://www.extsw.com/collections/12mm-id-316 Be sure to order a few extras as you will always need these to mount your caliper.

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You will also need longer bolts. I used M12-1.25 x 45mm 10.9 bolts. Here is the caliper bolted up to the knuckle with the machined spacers and longer bolts.

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The next step is figuring out how to mount the rotor to the hub. The stock 80 rotor has threaded holes and bolts up behind the hub. The 5th gen 4Runner rotors are slip-fit in stock configuration. Our hubs will not work for slip-fit unless you do a lot of machine work to the hubs, something I didn't want to do. So we're gonna bolt them up in a lugcentric configuration.

For this I used longer M12-1.25 x 40mm bolts and M12-1.25 open-ended acorn bulge lug nuts. Here's the hub taken apart with longer bolts.

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Back side of the hub. You'll notice I had a hub centering ring here. Based on what I read from others, they recommended 108mm to 106mm rings to help center the hub over the rotor. However I feel this isn't needed because of the lug centric nuts we're using.

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The back side of the rotor showing the beveled hole which matches nicely with the acorn bulge lugnuts.

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I used orange Loctite and cranked them down to about 14 3/4 Ugga Duggas. Here you can see the hub centering ring still installed.

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Here's the approx 2mm difference between the hub and the rotor with the ring removed after you tighten everything down. As I mentioned, several people have been running these for a few years now with no issue. It's really no different than when you install aftermarket wheels in a lugcentric setup vs OEM wheels that are hubcentric.

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And the final assembly

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As mentioned above, the 4Runner has a deeper rotor hat and since we simply bolted it to the back of the 80 hub, it will sit deeper over the knuckles. This means you need to do a little bit of grinding to clear the rotor. Here you will see the spots that required grinding on my knuckle. The grinding on the back steering stop is to clear the caliper. Because I'm running Hellfire knuckles with more material up top, I had to do a bit more grinding to clear the nut and a socket due to the caliper being spaced back by about 10mm. All in all this is quickly taken care of with a flap wheel.

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NOTE: since I'm running high-steer and don't have lower steering arms, I had nothing to grind here. But your lower steering arms will also require a bit of grinding to clear the rotor.

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With that out of the way we can mount the rotor/hub assembly back on the spindle. Here's the final clearance after grinding.

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Lower caliper mount.

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And we can finally put the caliper over the rotor!

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The 9.52mm machined spacers are just about perfect. With everything mounted up, I measured the distance between the surface of the rotor and the inside of the caliper housing. Not sure if this is the best place to measure but it's where I could get a consistent flat surface. With this setup I'm at about a 1.3mm difference between each side which is 0.05", basically nothing. I really don't see this causing an issue but if you really needed it to be perfect, it seems like an 8mm wide spacer would be just right.

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Muchas gracias por todo este recuento! Realmente esta muy claro…. Saludos desde Bogota - Colombia
 
This is on my list now. Thanks
Someone asked earlier about cost and I like money more than baldilocks does so here's my quick break down with rock auto. Let me know if I'm missing anything.

$200 - T100 booster and MC
$315 - 5th gen calipers rotors and pads
$100 - beer, fluid, cigars, nuts and spacers.
do you know the part number of the bigger booster of the t100 model
 
Ebay, carid and autoplicty all show them instock
 
Im having trouble finding a seiken 650-71450 booster, anyone have a source, or a different manufacturer of good quality??

Part# BBN60792 @ Cruiser Outfitters
Japanese Brake Booster - 1993-97 FZJ80 Disc/Disc
$327.50

5+ In-Stock and we can still ship today if you call soon: 801-563-1277
 
It sucks. I am running 14" rotors with gigantic dodge floating calipers from a 2014 3500 or something. Still sucky.

Master cylinder / caliper piston sizes are a zero sum game, you just need them sized sufficiently to not exceed a certain workload.

Bigger rotors/swept area can make an improvement with no downsides (other than the need for more heat dissipation) so that's a win.

But at the end of the day, I believe the booster is insufficient. Hydroboost is neat but I'm a bit worried about the flow requirements of the downstream box/piston for steering. I would like to see universal electrohydraulic boosters become more mainstream. The one in the 100 is ridiculously better even with the stock master cylinder size than everything I've done to the 80.
You might like this:


According to bosch, it works with 9.8v or greater to provide up to 6.2kN (1400lbf) of assist.

Basically, the 2018+ honda accord brake booster has a 2nd gen bosch ibooster for $150-200 and you can tune the assist by changing out the spring inside if you are careful to not tear the ribbon cable. Only needs 3 wires: power, ground, and signal from your ignition.

Of course, that's a lot of custom work to make it fit, and you may need to find new calipers again to get the appropriate hydraulic ratio.
Or, it would likely be easier to make another adapter plate to use your current master cylinder.
 
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You might like this:


According to bosch, it works with 9.8v or greater to provide up to 6.2kN (1400lbf) of assist.

Basically, the 2018+ honda accord brake booster has a 2nd gen bosch ibooster for $150-200 and you can tune the assist by changing out the spring inside if you are careful to not tear the ribbon cable. Only needs 3 wires: power, ground, and signal from your ignition.

Of course, that's a lot of custom work to make it fit, and you may need to find new calipers again to get the appropriate hydraulic ratio.
Or, it would likely be easier to make another adapter plate to use your current master cylinder.

Nice tip! I wonder how hard it is to swap masters
 
Im having trouble finding a seiken 650-71450 booster, anyone have a source, or a different manufacturer of good quality??

Part# BBN60792 @ Cruiser Outfitters
Japanese Brake Booster - 1993-97 FZJ80 Disc/Disc
$327.50

5+ In-Stock and we can still ship today if you call soon: 801-563-1277


Im a bit confused here.

Is the seiken booster listed above a t-100 unit to match the master? Or is it a non original equipment LC booster?

Is the t-100 master compatible with the original LC booster?

Essentially im asking if i NEED to replace my original brake booster to used the t-100 master cylinder..?
 
Im a bit confused here.

Is the seiken booster listed above a t-100 unit to match the master? Or is it a non original equipment LC booster?

Is the t-100 master compatible with the original LC booster?

Essentially im asking if i NEED to replace my original brake booster to used the t-100 master cylinder..?

No, the T-100 master commonly used with brake upgrades on 80's bolts to your existing booster. For those that need a new booster for use with their stock master or the T100, we offer them, part# BBN60792N shown above which fits the 1993-97 FZJ80/LX450 Disc/Disc oe application (or upgrades)

I've documented all of the Master cylinders for use on the 80 here. We've been selling/using the T100 replacements for quite some time including with our customers running the 4Runner brake upgrade.

 
I ran the numbers on that electric booster:

I see our brake boosters listed on ebay as an 8/9" booster, and know they are double diaphragm. I'm guessing one is 8, one is 9?
At 18 inches of murcury vacuum, we have 8.8 psi available to act on those diaphragms.
4 x 4 x 3.14 = 50.24 in^2
4.5 x 4.5 x 3.14 = 63.585 in^2
8.8 psi x 113.825 in^2 = 1,001 lbs of assist.

So right off the bat, you're at 40% more assist force. But the bigger difference is that instead of the air having to pass through a little foam filter and a valve and taking time to fill up the booster, this assist is almost instant. Since it's just a "dumb" booster, I don't think it would require modification to anything else in the system if you haven't modified other stuff yet.
 
Nice tip! I wonder how hard it is to swap masters
I scrounged around for some pictures, and actually it looks easier than I thought it would be.
The ibooster uses a 2 bolt pattern while the landcruiser uses a 4 bolt pattern, so a 1/4" steel plate with 7 holes and 4 studs is all that takes.

You will need to make an extension rod because of how recessed the push rod is.
If you don't have a lathe, just put the rod stock in your drill chuck and the drill bit in your vice.
It will self-center in the hole, so you can drill 1"+ deep holes while staying concentric with the stock.
gen 2 ibooster master cylinder side.PNG
fzj80 master cylinder mounting.PNG


I would use a bearing retaining compound (a loctite 600 series product) on the extension rod to the ibooster, because if there is an issue with the master cylinder's return spring it could cause the the extension to fall out and result in a complete loss of braking.
Alternatively, if that pushrod in there is threaded, then it's just a coupling nut and more threaded rod. (you can buy metric grade 12.9 threaded rod off McMaster Carr).

You will need to drill some new holes in the firewall. The rectangle, besides likely not having the same dimensions, appears to be rotated about 40 degrees. (this pic is of the cheaper Honda accord brake booster)
fzj80 booster firewall.PNG
gen 2 ibooster firewall side.PNG
 
Our hubs will not work for slip-fit unless you do a lot of machine work to the hubs, something I didn't want to do.

To get the slip fit would you just need to turn down the OD of the hub? Assuming you did this, and slip fit those rotors, wouldn't that impact how the caliper lines up? At the least no more spacer but would it move the rotor out too far? Would you also have to machine the surface of the hub the rotor sits on to get it in the right position?
 

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