Rear Disc Conversion Information

I'm not posting this to argue which is better for the Tacoma--disc or drum. I'm posting this to document my research and hopefully conversion to disc on my Tacoma. This is something I've been researching for a while. Quite simply, I hate drum brakes for a variety of reasons and would rather have rear disc brakes. I thought there would be a multitude of options that aftermarket vendors would be producing. So far, that is not even remotely the case. Here's what I've found so far:

Option 1:

SOS Performance. They have a one-stop kit to perform the conversion. If I'm reading their site correctly, it comes out to approximately $1100 for the entire thing. This is way too expensive for what it is, in my mind. For a few hundred more bucks I could have the an entire used rear-end from a 4-runner. Also, their instructions are pretty pathetic.

Option 2:

SOS Performance. They sell a kit that is just the hardware, backing plate, and emergency brake cables. It runs $340. I still think it's a little overpriced, but it is what it is. From here you can source the rest. From what I can see you will need a few parts from the dealer and the rest can be had from any auto parts store. You will need:

Calipers, caliper brackets, rotors, parking brake shoes, parking brake hardware kit, and brake lines. From Rock Auto I was able to find a mostly complete kit from a manufacturer I've used for pads a lot. I also added in braided lines. The total was approximately $300.

From the dealer you will need part numbers: 47613-60020 x2, 47612-60020, and 47611-60020. This is two struts that spread the top of the brake shoes and two parking brake cable actuators. They might be able to be sourced elsewhere, but I wasn't taking any chances.

Option 3:

You may have run across a thread or two about Unique Power conversion kits. It looks like they were pretty cheap at some point, but you can't order from their really crappy website. I emailed them and eventually got turned over to Pedder's USA distributor. I have zero information on the kit, other than the price: $1674. I did laugh when I saw that.

https://pedders.com/blogs/news/pedders-trackryder-rear-disc-conversion-kit-toyota-tacoma-2005

This is what I have so far. I have not ordered anything. Although I think it's obvious which route I'll go. Once I get everything together I'll probably make a DIY video or write-up.

 

Does the master cylinder need any type of adjustment or change to use rear disks?

 

According to SOS, no. They do, however sell a master cylinder off another vehicle (01-07 Sequoia) that may work. I say may because it says it won't work with vehicles with vehicle stability control. It claims to give a firmer pedal.

 

Good luck, I look forward to seeing you go through with this.

 

Thanks! I'll try and keep this up to date!

 

Hey @crashdb ! I have done the rear disc conversion with the full kit from SOS performance. I am also about to do the master cylinder swap, as it is not required, but it helps a lot. Without it, you only get about half the rear brake line pressure you need to actually use the rear discs, as it stands right now I am mainly stopping with my fronts and hardly even engaging the rears which is safe but not ideal and also gives you that mushy pedal feeling. Another user on TW informed me that the Disc/drum master cylinders have a "knee point" where up to that point the fronts and rears build equal pressure (but its only 500 psi), and after that point the fronts build pressure and the rears barely do. At full depression of the pedal the front might get as high as 2kpsi whereas the rears will only develop about 700 or 750 psi, which translates to the front doing the vast majority of any braking required past that knee point. For most that may not even affect their driving experience but I didn't spend what I did on parts to deal with another handicap, so in the Sequoia MC goes! I should have a write up of my process sometime next week

P.S.: Youre exactly right about the instructions, they really failed miserably for trying to figure out the order to install the miniaturized brake drum components. Ended up doing it out of order about 10 times, if anybody wants to know the ideal order to put a drum brake together I got you

 

Thanks for the information! Be sure and post a link to your write-up for the master cylinder.

 

You got it man! Will do

 

@stevotivo12 Have you confirmed that the master cylinder will work? SOS says it won't on vehicles with VSC; which we have. On the other hand, our master cylinder looks like the one in the picture on the website. I'm a tad confused, I must confess.

 

I know how you feel, the instructions on the SOS performance site are for shit. So basically, there WAS a VSC master cylinder for '05-'12 tacos that had a bunch of electronic sensors and stuff coming off of it to make VSC work. The new '16 up tacos have a different design to the VSC system where those sensors are mounted elsewhere, probably inside the ABS unit, but either way the master cylinder is compatible because it was all those sensors that make the difference! I will post some pictures and info when I do the swap but I have been assured that the swap will work on the new trucks with the possible exception of the Pro and Off-road models as I do not know much about their brake system other than they use a hydraulic/electric brake booster which may or may not complicate an install such as this!

 

Ah. Good. There's something over on the passenger side. ABS or something. I've never looked at it very much. Anyway, thanks for clearing the confusion. I was hoping it wouldn't work so I could save some money. Never seems to work that way!

 

@crashdb as promised, here is a link to my Brake Upgrade thread and my MC install write up! It is at the bottom of the linked page: https://www.tacomaworld.com/threads/big-ole-brake-upgrade-thread-for-third-gens.525568/page-4

 

Thanks! I ordered everything but the master cylinder. Fun times ahead!

 

the old days, you just installed an adjustable proportioning valve and called it a day... is this not applicable anymore in light of the new electronic, well, everything?

 

Not really. And a proportioning valve won't make this kit work anyway, because it can't actually make the master cylinder push enough fluid to the rear. All it can do is restrict the front.

I should be old enough to not be surprised that somebody is selling a kit that lets you give away your rear brakes for decorative ones as an "upgrade" but I still am.

What does amaze me is that the kit doesn't work, people know that, and people still install it!

OP, simply put, if your disk brake "upgrade kit" doesn't include a different master cylinder, it will make your brakes worse.

 

I'm not asking this to start an argument. I'm asking because I want facts that may change my decision to do this. I'll agree that a master cylinder is needed for the full performance, but I don't believe it's absolutely necessary. A quick search online reveals many disc conversion kits from reputable aftermarket manufacturers does not include a master cylinder inless it's a change to power brakes. I fully plan on adding a master cylinder at a later date, but it could be a bit. If the rear brakes weren't working at all it would be obvious by surface rust on the rotors. Again, I'm not trying to start an argument. I'm looking for information. Thanks.

 

You do realize that there's a difference between "working somewhat" and "working less than your factory brakes?" If your only criteria for your rear brake "upgrade" is "works enough that the rear rotors don't rust" then I don't know what to tell you.

I come from a road-racing background so my list of "reputable brake manufacturers" is very short - ATE, Brembo, Wilwood, Bendix (maybe), Stoptech (very maybe) and ZW if they're having a good day. The simple fact of the matter is that your total braking system performance will be degraded if your brakes are out of balance, as a change from rear drums to rear discs is almost certain to do barring some very careful caliper selection or simply using the correct master cylinder.

I don't have a thing against the idea of converting to rear discs (aside from thinking it's unnecessary on these trucks), assuming you use a good sliding rear caliper, but, simply put, you must use the appropriate master cylinder to avoid degrading your brake performance. For my money, and I haven't looked into this extensively, your best bet is probably going to be to transplant the entire 4-Runner system, if that's possible.

edit to add: having looked at the SOS Performance website, it seems that they offer a kit based around the 4-Runner rear caliper and also sell the appropriate master cylinder. So that's just fine. I would strongly advise against getting the fancier Stoptech fixed 4-pot calipers, as they are inappropriate for our semi-floating rear axles.

 

Exactly. Tires and correct piston pressure that correctly match the brake bias to the (inherent to pickup trucks) uneven weight split of the vehicle is key.

 

good luck! subbed.

 

Pickups are especially hard to develop good braking systems for, because their load situation is designed to change radically. Most of the time most of them will be driven with empty beds, but they still need excess capacity for when they're loaded, and when they're loaded they can very easily go from 70/30 F/R to 50/50 or more. It's not an easy problem to work.

Racing cars are much simpler! At least the weight stays where I put it in those. Unless I crash.