Jeep2.0
New member
No problem man - Shane's a good guy. Let me know if you need a 2nd one for any reason.
Looking forward to the final result. I have access to a knee mill to cut that slot too. :clap2: :rock:
My own JK 'Big Brake' research:
- Thread starter Majik
- Start date
No problem man - Shane's a good guy. Let me know if you need a 2nd one for any reason.
Looking forward to the final result. I have access to a knee mill to cut that slot too. :clap2: :rock:
Thardin
New member
X2
Awesome thread. I am running Reid knuckles and Spyntechs with Raceline wheels. This will be on my list for sure!
Subscribed! Been following from the beginning, but just got my acct set up. Looking forward to the final product as I need a brake job anyway. But couple questions, maybe I missed them, but will the replacement master pump enough fluid to supply all four upgraded calipers? And to keep costs down what about using the stock fronts in the rear? They are plenty large in comparison, and may not need a ton reworking like the fronts.
Oh and I should mention that I manage a auto parts retail store so if needed for the project I can order and mic any dimensions needed. Or do test fits and report back. I started this same project about the same time but just didn't have a chance to fully invest myself... but am willing to help!
J.
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Oh and I should mention that I manage a auto parts retail store so if needed for the project I can order and mic any dimensions needed. Or do test fits and report back. I started this same project about the same time but just didn't have a chance to fully invest myself... but am willing to help!
J.
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Majik
Member
Thanks, buddy! I just may end up taking you up on that offer!! :thumb:
Majik
Member
Have been out of town this week with kids on vacation. Back in town on Wednesday. Have more parts being delivered by Brown Santa even while gone and my neighbor keeps putting them in my garage 
. So there is plenty of inspiration to get the brakes done, I promise!! Had to hunt for some bolts to attach the used unit bearing so graciously mailed to me by a forum member to my knuckle used for the mockup. That took a while. Expensive from the dealer. Fastenal helped though
All that's left is finalizing the adapter shape and dimensions. Will post asap!!
Thanks for the interest and bearing with me working this project around thew rest of my life!!
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. So there is plenty of inspiration to get the brakes done, I promise!! Had to hunt for some bolts to attach the used unit bearing so graciously mailed to me by a forum member to my knuckle used for the mockup. That took a while. Expensive from the dealer. Fastenal helped though All that's left is finalizing the adapter shape and dimensions. Will post asap!!
Thanks for the interest and bearing with me working this project around thew rest of my life!!
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Subscribed! Will your concept also work on the non-rubicon Dana 30? I too have the spyntec conversion, best investment yet.
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Also, how will all of this coexist with the Electronic Suicide Program (ESP) ?? Not that mine is much of an issue anymore. Presto snippo ! No matter what I tried I never could get it to settle down so it has a toggle now.
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your not changing any electronics or the tone rings at the end of the axle, so will not affect the ESP. :rock:
Yes, but what happens when ESP freaks out? It takes it upon itself to apply your brakes for you, individually I might add, brakes that are now bigger and possibly more responsive? I'm not saying this is a bad idea, it's a wonderful idea as long as things works and plays well together.
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Majik
Member
Yes to the non Rubi question. The brakes on the Dana 30 are the same, thus the same mounting hole locations on the knuckle, and that's all that really matters for this swap.
As far as your ESP question: yes, there should not be any issues. The calculations and caliper selection I have done will allow factory master cylinder use. I also have a bolt in MC option from a late model Dodge Nitro that is exactly the same MC as the JK but with a tiny bore increase. That will give a firmer pedal but one that requires a touch more force from your leg to reach peak braking. It really will be personal preference on that issue.
The caliper piston surface areas, though there are four now in each caliper, are quite similar to the single large piston in the factory caliper. So no significant increase in fluid flow is needed. The braking increase comes from the massively larger rotor, the more even application of force from four smaller pistons, and brake pads with a much higher coefficient of friction. So, the ESP won't know the difference.
It should be noted that when I started this project I was really fixated on big caliper piston surface areas. The problem with that is that I couldn't find a master cylinder with a big enough bore to push enough fluid to make them work. I had the opportunity to drive a jeep locally with a company's popular big brake upgrade. It uses a caliper from Dodge Ram 1500 pickups. This JK had the upgraded master cylinder and I felt the brakes took too much travel of the pedal to achieve the 'improved braking'. When I did the calculations, it became evident why. Those big truck calipers need a lot of fluid behind those twin pistons. That means a huge master cylinder bore of 1.25" or bigger, OR a long stroke of the master with a brake pedal ratio adjusted to allow that without your foot having to move 18". A pickup truck has room under the hood for either, and there is also tons of space under the dash for a long brake pedal lever. Our Jeeps have exactly the opposite, unfortunately. In fact, the MC in a JK is nearly the shortest on the market for any vehicle due to the space constraints under the hood. And nobody makes a midget master cylinder with a huge bore. Trust me... I looked...even at custom brake system fabricators.
Not to say that that JK I drove with the popular brake upgrade didn't work a bit better than stock, and I am so appreciative of all companies that try to improve the performance of our rigs. (Most companies that have done this have been able to produce a bolt-on installation, and there is benefit in that! I have already had to perform a mod to the knuckles that now makes it slightly less than bolt on.) It's just a pedal feel and travel I didn't personally enjoy, and the reason is clear in the numbers. So, I had to improve all the other aspects I mentioned. I CAN use a stiffer, more efficient fixed caliper. I CAN use much better biting pads (who cares about dust in this application). I CAN use a HuGE rotor! (Which gives us 20% more brake torque even if I changed nothing else and used the stock caliper!). So I identified the factors that affect raw brake torque, found which ones I could control, and found one, the MC size, that severely limited me. In my opinion, and I am by no means an expert, any brake system upgrade that attempts to use a big bore surface area caliper on the JK, without a matching significant MC upgrade (which simply won't fit in a JK), will never be able to reach ideal performance. The numbers show it. I hope my project provides the results I aim for, and I promise to be honest with everyone here. If it doesn't work ALOT better than stock, I will tell you.
Hope I kept your attention
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As far as your ESP question: yes, there should not be any issues. The calculations and caliper selection I have done will allow factory master cylinder use. I also have a bolt in MC option from a late model Dodge Nitro that is exactly the same MC as the JK but with a tiny bore increase. That will give a firmer pedal but one that requires a touch more force from your leg to reach peak braking. It really will be personal preference on that issue.
The caliper piston surface areas, though there are four now in each caliper, are quite similar to the single large piston in the factory caliper. So no significant increase in fluid flow is needed. The braking increase comes from the massively larger rotor, the more even application of force from four smaller pistons, and brake pads with a much higher coefficient of friction. So, the ESP won't know the difference.
It should be noted that when I started this project I was really fixated on big caliper piston surface areas. The problem with that is that I couldn't find a master cylinder with a big enough bore to push enough fluid to make them work. I had the opportunity to drive a jeep locally with a company's popular big brake upgrade. It uses a caliper from Dodge Ram 1500 pickups. This JK had the upgraded master cylinder and I felt the brakes took too much travel of the pedal to achieve the 'improved braking'. When I did the calculations, it became evident why. Those big truck calipers need a lot of fluid behind those twin pistons. That means a huge master cylinder bore of 1.25" or bigger, OR a long stroke of the master with a brake pedal ratio adjusted to allow that without your foot having to move 18". A pickup truck has room under the hood for either, and there is also tons of space under the dash for a long brake pedal lever. Our Jeeps have exactly the opposite, unfortunately. In fact, the MC in a JK is nearly the shortest on the market for any vehicle due to the space constraints under the hood. And nobody makes a midget master cylinder with a huge bore
. Trust me... I looked...even at custom brake system fabricators.Not to say that that JK I drove with the popular brake upgrade didn't work a bit better than stock, and I am so appreciative of all companies that try to improve the performance of our rigs. (Most companies that have done this have been able to produce a bolt-on installation, and there is benefit in that! I have already had to perform a mod to the knuckles that now makes it slightly less than bolt on.) It's just a pedal feel and travel I didn't personally enjoy, and the reason is clear in the numbers. So, I had to improve all the other aspects I mentioned. I CAN use a stiffer, more efficient fixed caliper. I CAN use much better biting pads (who cares about dust in this application). I CAN use a HuGE rotor! (Which gives us 20% more brake torque even if I changed nothing else and used the stock caliper!). So I identified the factors that affect raw brake torque, found which ones I could control, and found one, the MC size, that severely limited me. In my opinion, and I am by no means an expert, any brake system upgrade that attempts to use a big bore surface area caliper on the JK, without a matching significant MC upgrade (which simply won't fit in a JK), will never be able to reach ideal performance. The numbers show it. I hope my project provides the results I aim for, and I promise to be honest with everyone here. If it doesn't work ALOT better than stock, I will tell you.
Hope I kept your attention
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Last edited:
Majik
Member
Oh, and just got the test knuckle back from the machine shop after a minor adjustment to my prior mod. This allowed me to make the necessary bolt on adapter brackets much thicker and thus stronger. Approx 3/8" thick chromoly plate should be PLENTY strong! Should have a test fit later this week!
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Majik
Member
...and one more thanks to jkbud for donating that unit bearing!! :rock:
It has helped immensely and allowed me to assemble and test fit the knuckle, bearing, rotor, and caliper right on my workbench. No squeezing calipers and micrometers in the wheel well...no banging my head trying to check clearances...
Jkbud... Much appreciated!!
It has helped immensely and allowed me to assemble and test fit the knuckle, bearing, rotor, and caliper right on my workbench. No squeezing calipers and micrometers in the wheel well...no banging my head trying to check clearances...
Jkbud... Much appreciated!!
Have you been able to find out what year and model your spyntec rotors are from ? They don't seem to be very inclined to give me that info for some reason.
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If you dont mind Majik, somewhere along the line I was told part of the hubs were sourced from a TJ (or was it CJ ?).
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Funny thing is, mine were'nt "re-drilled". The set that came in my hub kit slipped right on.
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