Front brake 95 4runner calipers on 85 FJ60

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Spanky Pete

Spanky Pete

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Dec 21, 2008
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I have read the old posts and searched and searched,but I am still unclear on several points regarding the conversion to 4runner calipers.

I have a stock suspension 85 FJ60. Drum brakes in the rear. Stock wheels.

I just bought 95 4runner disk calipers: S13WB (the bigger V6 ones?)
31.99 from O'Reilly's in stock. Everything but the pads.

I do not plan on replacing the master cylinder. I was hoping to just bolt these calipers on with some new ceramic pads, bleed them at the caliper, replace rear drum shoes and hardware, adjust rear drums and drive.

Has anyone done this on stock fj60, stock wheels, 95 4runner calipers?

Do I need to get longer hard lines at the caliper? Do I need to grind the caliper when using the stock rims? How much of the backing plate/dust shield needs to go? I ask, because I don't have a grinder or cut off wheel and I am wondering if I can get away with using a file or other less industrious method.

Thanks
 
I have '95 4Runner calipers on a FJ60 with stock wheels. Calipers did not have to be ground and the wheels do not rub. Stock brake lines will work. Backing plate can be trimmed with a hacksaw.
 
Godwin said:
I have '95 4Runner calipers on a FJ60 with stock wheels. Calipers did not have to be ground and the wheels do not rub. Stock brake lines will work. Backing plate can be trimmed with a hacksaw.
Click to expand...

did it make a big stopping difference
 
I used calipers from a '96, bolted right up - didn't even need to trim the dust shield on the one side because it has pretty much rusted away! Hardest part was remembering to get pads for a 4runner and not for the Cruiser!

Like Godwin said the stopping power in noticeable (but not dramatic) seems to brake better in heavy braking situations. I have also noticed better braking when the truck is loaded with more weight.

For the cost/ effort and benefit I think it is worth it.

j.
 
Godwin, you say stock pads will work with the 4runner calipers?
 
Godwin may know differently but I am going to say no stock LC pads will not work with 4runner calipers. One of the benefits to using the 4runner calipers (aside from larger pistons) is that they also have larger pads and therefore more braking surface which should mean better stopping power.
 
Yeah, the 95 4runner calipers I used required larger pads. I finished this up a while ago. It was very easy. Hack saw did just the trick to trim a little from the old dust shield. Stock wheels, brake lines, and M/C all worl great with these calipers. Noticeably better braking, not night and day, but noticeable.

I also rebuilt the rear drum brakes. Anybody have any problems with Brake Best brand wheel cylinders? No probs yet, but would like to know if anyone else found out they are junk, before I found down the road.
 
MYFJ62 said:
Godwin may know differently but I am going to say no stock LC pads will not work with 4runner calipers. One of the benefits to using the 4runner calipers (aside from larger pistons) is that they also have larger pads and therefore more braking surface which should mean better stopping power.
Click to expand...
FWIW this is one of the most commonly misunderstood things about disc brakes. The larger pad really only adds life-span because it adds friction material volume. There is no accounting for the pad area in the friction braking force calculation.
The formula looks like this:
Operating Pressure X Piston Area X Pad Friction Coefficient X Radial Distance of Pad Centroid = Braking Torque.


I'll confirm that my old FJ60 pads would not fit in the 4rnnr calipers.
 
I thought the 4-runner Master Cylinder was bigger and therefore would give you more braking power/shorter stopping distances ????
 
Hydraulic Force Multiplication

A larger m/c piston means that you have to push harder to get the same line pressure. A larger m/c piston means that the pedal will be firmer and travel less total distance. A high, firm pedal is confidence inspiring, but probably is not the best possible stopping power.

Larger caliper pistons mean that you get more clamping force from the same line pressure. Larger caliper pistons mean that the pedal will be less firm and will travel more total distance. A slightly mushy, low pedal isn't confidence inspiring, but can actually be very good stopping power.
 
It's simple volume mathematics. The line pressure will be X based on how hard you push, this is determined by everything from the pedal length (a longer pedal off of the axis of rotation will push harder), the valving size in the master cylinder, brake booster, etc. That X will multiply by the surface area of the piston. If the piston area moves from 1 to 1.5 (hypothetical units) then more fluid will be required to fill the area. As the pressure builds up to X that will be applied across the surface area of the piston, it will be pushing harder on the brake pad with the 1.5 piston compared to the 1. So any increase in surface area of the pistons (surface area perpendicular to the motion of the piston, AKA the piston diameter) will squeeze the rotors harder. Bigger caliper bore = greater clamping force.
 
just like ntqsd says, "slightly low, mushy pedal". That describes the pedal travel andforce required to brake after the caliper swap. It was unnerving the first drive around the block, but now, I really like the braking feel. I have good control over my stopping. Avoided a near rearend collision just the other day.
 
At the risk of offending people that made this change successfully and are very happy with it (apologies to you), the 4runner caliper mod is one of the most overrated and questionable upgrades of all. Where this mod comes in handy is when you plan on doing rock crawling with 38s on it.
Often people have badly maintained braking systems and think the bigger caliper/master is the cure-all.
BEFORE you do the mod, fix your brakes. get rid of old and bulging rubber brake lines, check the calipers, get rid of those old and burned rotors, the glazed pads, adjust your rear brakes properly, the load proportioning valve, put in new shoes into good drums in the rear, make sure the master is ok and the booster operates properly, bleed the system form the old and brown fluid and you will be amazed how well the system actually works.
A properly stock Cruiser braking system will stop a fully loaded wagon on 33s on a dime. If it does not, there is something wrong with the system.
cheers,
J
 
If you don't believe Jan about the hoses, have a friend stomp hard on the pedal while you have a tight grip onto one of your old rubber brake hoses. Most folks figure that they're fine so long as they're not leaking. Not true!

My thinking in going straight to the 4rnnr calipers was that it was a small upgrade over stock (& one must be careful in changing pistons sizes!) and that I'm replacing the calipers anyway. With any luck this swap will put me back equal to stock braking effectiveness on stock sized tires with my 33-10.50's. Though I don't expect that it will get me all the way there.
 
ntsqd said:
FWIW this is one of the most commonly misunderstood things about disc brakes. The larger pad really only adds life-span because it adds friction material volume. There is no accounting for the pad area in the friction braking force calculation.
The formula looks like this:
Operating Pressure X Piston Area X Pad Friction Coefficient X Radial Distance of Pad Centroid = Braking Torque.


I'll confirm that my old FJ60 pads would not fit in the 4rnnr calipers.
Click to expand...

This is true... up to a point. That being the point of complete heat saturation of the pads. The goal of the brakes is to turn kinetic energy into heat. Smaller pads cannot absorb as much heat as larger pads. So under normal circumstances, there may not be a noticeable difference. When you're going down a steep canyon with a trailer behind your rig, you most likely will notice a difference.
 
That is Pad Fade and not braking torque (power). Friction materials tend towards being more of an insulator and less of a conductor, where the rotors are much better conductors. Which is why if you're experiencing Pad Fade (as opposed to fluid boil) the cure is better ventilation by going to a rotor with a better vane design or one that has more air gap through the center, some ducting to the center of the rotor, or even a larger OD.
 
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