Rear Disc Brake Conversion Kit

***ALL DISC BRAKE CONVERSION KITS ARE SOLD AND PRODUCTION IS ON HOLD UNTIL FURTHER NOTICE***
More details provided in post #380 for those interested.

Disc Brake Conversion Kit:

This is a bolt on kit to replace the rear drum brakes with disc brakes.




What's included:

- Conversion brackets & spacers (1 pair for 1 axle).
- All hardware to mount the bracket to the axle and the caliper to the bracket.


What's required:(details below)

- '94-'04 Mustang Cobra rear calipers & caliper mounting bracket.
- '94-'04 Mustang Cobra rear brake pads.
- 2003-present 4Runner rear rotors.


CAD Images:










The Brackets:

The brackets are laser cut from 3/8" A36 steel. The spacers are also laser cut from A36 steel to match the brackets. Both the brackets and spacers are Zinc Yellow-Chromate plated to prevent corrosion.

The brackets are designed to fit the factory 4Runner axle housing with ABS.

The spacers are required to get the proper offset for the caliper mounting bracket. They allow the rotor to fit properly in the caliper mounting bracket.


Parking Brake Kit:





I completely re-worked my junction bracket to increase the force applied to the caliper. Instead of using off the shelf parts that I used in the first version on my 4Runner, I designed new parts and had them fabricated to provide the best mechanical advantage in the space available. The junction bracket now incorporates a lever and pulley to increase the mechanical advantage over the 1:1 ratio of version 1. The 4Runner parking brake cable enters the junction bracket through the aluminum fitting in the front, loops around the pulley, and ends by securing to the zinc-yellow fitting.

The kit includes everything required to connect the parking brake in a way that I'm comfortable having my name associated with. Here's an example of what is included.

- (2) brake cables for the Mustang calipers.
- Factory clips to secure the cable on the caliper.
- Junction bracket for the cables.
- Fittings to adapt the factory cable to work with the junction bracket.
- All necessary hardware (all 18-8 stainless steel).
- Spare rivet nuts, just in case you need them. Or if you haven't used them before and need to experiment before installing on your 4Runner. The correct size drill bit for the rivet nuts is also included.


Brake Line Kit:



These brake lines replace all the brake lines on the rear axle. The copper-nickel lines replace the hard lines from the axle mounted "T" to the outside of the axle. They mount using the factory tabs. The stainless steel braided flex lines connect the copper-nickel hard lines to the caliper.

The year must be specified for the brake line kit due to the changes in the ABS system. There are two different sets of hard lines, one for '96-'00 and one for '01-'02.




Installation Instructions:
Click here.




weekendclimber's video install:

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<iframe width="560" height="315" src="https://www.youtube.com/embed/ziPwMFUddb0" title="Rear Disc Brake Conversion Part 2 - 3rd Gen 4Runner ('96-'02)/1st Gen Tacoma ('96-'04)" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>




*****These brackets have not been tested/approved by the DOT and are recommended for off-road use only*****

What's Required

Calipers:

- '94-'04 Mustang Cobra rear calipers.

The Cobra part is important. The difference is in the caliper mounting bracket. The rear caliper itself is the same for all '94-'04 Mustangs. The Cobra came with a thicker, vented rotor. The caliper mounting bracket was different to allow more room for this thicker rotor. The 4Runner rear rotor is also vented. It needs the wider gap in the Cobra bracket to fit properly.

The easiest way to tell if you have the correct caliper mounting bracket is to look and see if the outside of the bracket is connected. If it is, you're good to go. You would think this is easy, but even the auto part manufacturers mess it up. I've purchased part #14-1042 from Cardone, BrakeBest, and Wearever. All of them have gotten it wrong. That is the part number for the correct caliper mounting bracket. Always open the box and look at the mounting bracket before you leave the store. It's about a 50-50 chance if the properly labeled box has the right part in it or not.

These are not my images, but they show the difference in the two brackets.






Brake Pads:

- '94-'04 Mustang Cobra rear brake pads.

If you want to make life easy, go with brake pads for a '94-'04 Mustang Cobra. The pad is slightly thinner to account for the thicker rotor. As mentioned, the caliper is the same. So in order to fit a thicker rotor in the same amount of space, the pads are thinner.

You can make pads from a non-Cobra work, but they will either be pretty tight until the get worn down or you will have to run them without backing plates/pads until they wear down a bit. They are much more difficult to fit and assemble than Cobra pads.


Rotors:

- '03-current 4Runner rear rotors.

When used with the Cobra caliper mounting bracket, these rotors fit great. The best thing about them is that they are a Toyota part and they don't need to be modified. The Montero rotors that have been used in the past have interference issues with the Toyota lug studs and the back of the rotor hat needs to be countersunk to correct the issue. This is not an issue with the newer 4Runner rotors. Everything fits without modification.

Brake Kit Background

I've been running version 1 of this conversion since 28JUN17. It was installed on my 4Runner when it was at 233,910 miles. It now has over 279K miles, so over 45k miles on the kit so far. I used the lessons I learned from my first kit to develop these brackets and I'll be upgrading to a set as soon as they're finished. The biggest thing I learned was the difference between the Cobra caliper mounting bracket and the others. My first set of brackets used the non-Cobra mounting brackets and it caused the tolerances to be very tight.

Here's a few pictures of the version 1 brackets after install.

You can see in this picture that it's the wrong caliper mounting bracket.




In this picture you can see how tight of a fit it is between the caliper mounting bracket and the rotor.







On 15JUL18, I finally got around to connecting the parking brake. I'm sourcing the parts now to be able to offer this as a kit for those interested.

Status Update

Picked up the first run of brackets from the shop today.




Test fitting:

Picture from inside with the caliper mounting bracket in place.




Caliper mounting bracket, spacer, conversion bracket.






Rotor and caliper mounting bracket.






With brake pads.






Now I have a 64lb box packed and ready to go to the shop for plating. How to make friends with USPS employees :wow:

What years work for the Mustang calipers? This kit, a line lock, and a t-case brake are probably in my future.

theesotericone said:

What years work for the Mustang calipers? This kit, a line lock, and a t-case brake are probably in my future.

Click to expand...

Details added above.

I recommend against a t-case brake. I ran one on my Tacoma for a while and it was a pain. Getting it set up was difficult and part availability was another problem. I can provide the parts to connect the parking brake of the Mustang calipers to the factory hand brake. I've been running that on my 4Runner for a while and it's much nicer than the t-case brake was on the Tacoma.

midcoma said:

Details added above.

I recommend against a t-case brake. I ran one on my Tacoma for a while and it was a pain. Getting it set up was difficult and part availability was another problem. I can provide the parts to connect the parking brake of the Mustang calipers to the factory hand brake. I've been running that on my 4Runner for a while and it's much nicer than the t-case brake was on the Tacoma.

Click to expand...

First and foremost, I applaud your work, and I appreciate it. Two questions, how smaller are these calipers than the tundra calipers? It would drive my OCD nuts if I knew I had little baby rotors on the rear of the rig. Second question is isnt drum brakes better for off road? Thats the excuse toyota uses to still put factory drums on all new off road vehicles today.

I'm in, and in for the parking brake kit as well.

I'm in also , and in for the parking brake kit as well.

I’m in for a kit and parking brake assembly


One question, do you need to upgrade the master cylinder for this kit? I have 199mm tundra brakes on the front

midcoma said:

Details added above.

I recommend against a t-case brake. I ran one on my Tacoma for a while and it was a pain. Getting it set up was difficult and part availability was another problem. I can provide the parts to connect the parking brake of the Mustang calipers to the factory hand brake. I've been running that on my 4Runner for a while and it's much nicer than the t-case brake was on the Tacoma.

Click to expand...

I appreciate the first hand knowledge of the t-case brake but I've done the research. It's what I'll go with. The less crap I have hanging off the rear axle the better for how I wheel my rig. I'm still debating if I really even need a line lock. I do really want one though. Having the ability to lock one rear tire and pivot off it would be almost as good as front digs. lol

I'm in as well! Also interested in the parking brake kit too. Can't wait for this!

For sure interested in the parking brake kit if you would consider selling that separately. But I have a question about the cable routing, would going down from the frame to the control arm and under the axle tube limit suspension travel? Thanks

I want it. Take my money. I’m in for the parking brake too.

I'm very interested on this but would like to know if this increases braking power over the factory drums?

Super cool! Nice job! Cant wait to see some more installs.

This looks great! I would be interested in future orders including the parking brake kit.

I am also curious about the master cylinder and if combining this upgrade with the TBU would required changes to the cylinder.

I will have to do some searching to see experiences people have had with other rear disc brake set ups.

I am not one for non stock mods but I must say this solves the problem for the rear backing plates rotting away in the rust belt. Great job OP. Looks like a very solid setup and fairly easily to do.

Any chance that the conversion kits will come with rock shields for the rotor as a kit option? As small rocks can play hell on rotor and pads if they get in between the rotor and pad assembly. ;-)

VernySanders said:

How smaller are these calipers than the tundra calipers?

Click to expand...

From a quick search, it looks like the Tundra rotors are 12.6" diameter and the 4Runner rotors are 12.3" diameter. If you're talking about the calipers, the Tundra front, 4 piston calipers are much larger than the the Mustang rear, single piston caliper.

Here's my brakes for reference. 231mm Tundra up front, Mustang conversion on rear.

Front:



Rear:

VernySanders said:

Second question is isnt drum brakes better for off road?

Click to expand...

There are plenty of threads discussing the difference between drum and disc brakes. I'll just say that's it's personal preference. I prefer the rear disc for ease of maintenance on the brakes, axle bearings, and seals. They're also self-cleaning and don't trap mud.

RandyBobandy said:

One question, do you need to upgrade the master cylinder for this kit?

Click to expand...

I think it will depend on your overall brake set-up and what you prefer for the pedal feel. I upgraded my master cylinder, but I also have 231mm Tundra calipers up front and I removed my ABS. I've read of people converting to rear disc with tundra brakes up front, keeping ABS, and not having any issues with the stock master cylinder. There are too many variables to give you a solid answer.

eimkeith said:

This bracket, right?

Click to expand...

Yes; however, order more than you think you need. I ordered one from Amazon and it was the right part number, but the box contained the wrong bracket. So I suggest ordering maybe 4 and returning what you don't need because I expect not all of them will be correct.

theesotericone said:

Having the ability to lock one rear tire and pivot off it would be almost as good as front digs.

Click to expand...

I was wondering why you would want a line lock if you were using a t-case parking brake. That answers my question though. PM me if you need any more info about setting up a t-case brake. I may have some parts from my old set-up as well if you need them.

rexassian said:

Would going down from the frame to the control arm and under the axle tube limit suspension travel?

Click to expand...

I have a 4WheelUnderground rear 4-link on my 4Runner and the travel is not limited by the parking brake cables. There will be plenty of cable length for most rear suspension configurations.