Critique my brake build

6

64Chevy

New member
I did a test the other day, and I cannot lock (activate the antilock system) on my 2015 JKUR. It has 33's and all the trimmings (winch, armor, recovery gear, tools, etc.). So I gotta upgrade my brakes. I've been working with the very talented owner of the shop that has helped me with my track cars. We did some rough calculations to estimate brake line pressure and then rotor torque, as well as some guesses about brake pedal stroke. Here's his recommendation for the best "bank for the buck" upgrade.

J8 master cylinder and brake booster (these parts are included in the Mopar big brake kit).
Teraflex front brake double piston calipers, brackets, and rotors (he recognizes the caliper included in the Mopar big brake kit and doesn't like it for a variety of reasons)
Dynatrac rear brake kit (bigger rotors and caliper relocation bracket)

He went on the bigger diameter rotors generate more torque (leverage) and more square inches of caliper generate more torque (brake pad pressure) all things being equal. And while the bigger bore master cylinder decreases line pressure some, the upsized booster likely compensates, and the increase amount of brake fluid moved means a shorter pedal stroke (meaning better feel).

This isn't meant to suggest that just the Mopar big brake it, or the Dynatrac 4 wheel kit, or other options aren't also great.

Please let me know what you think? Also, I know Teraflex has a bad rep here--other than the fact that there stuff seems to be priced at a level above what it should be, is there another problem?
 
Why do you need to lock up the brakes? My stock brakes stop my jeep on 37’s no problem.

This sounds retarded.

Edit: lol just read your teraflex comment. Yeah sure they are only priced high. That’s it. Tard


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OverlanderJK said:
Why do you need to lock up the brakes? My stock brakes stop my jeep on 37’s no problem.

This sounds retarded.

Edit: lol just read your teraflex comment. Yeah sure they are only priced high. That’s it. Tard


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Click to expand...

I am retarded, but let me explain. I taught high performance driving for 15 years. I've actually done some analysis of pedestrian crash stats.

So maximum braking is actually achieved (on vehicles with antilock brakes) just before the antilocks activate--this is called threshold braking. The huge advantage of antilocks is that they allow you to steer while applying close to maximum brake at the same time. Personally, I have avoided one car to car accident, and one time when I would have hit an idiot suicidal biker, by having practiced this and used it.

Back to my point. Sometimes 5 feet is the difference between hitting something (or someone) and not. So the fact that I can't lock up my brakes (or, more correctly, activate my antilocks brakes) mean that my Jeep isn't stoping as good as it should. Further, should l cream something or someone, the lack of antilock stutter skid marks on the road is going to make me more guilty. But mostly, I hate (HATE!!!) the way my brakes feel. Hate them. In Moab, going down several steep pitches, I couldn't hold a constant speed. That sucks, and that could be dangerous.

But I was ignoring it up to the point I tried maximum braking. If you have ever known someone who's killed a kid with a car (even though it was not their fault) it is not something you'd wish on anyone except your enemies. I daily drive my rig, and I have to wind my way out through neighborhoods thick with kids.

I can handle being a retard, but I don't want to be a kid killer. You may feel differently...
 
64Chevy said:
I am retarded, but let me explain. I taught high performance driving for 15 years. I've actually done some analysis of pedestrian crash stats.

So maximum braking is actually achieved (on vehicles with antilock brakes) just before the antilocks activate--this is called threshold braking. The huge advantage of antilocks is that they allow you to steer while applying close to maximum brake at the same time. Personally, I have avoided one car to car accident, and one time when I would have hit an idiot suicidal biker, by having practiced this and used it.

Back to my point. Sometimes 5 feet is the difference between hitting something (or someone) and not. So the fact that I can't lock up my brakes (or, more correctly, activate my antilocks brakes) mean that my Jeep isn't stoping as good as it should. Further, should l cream something or someone, the lack of antilock stutter skid marks on the road is going to make me more guilty. But mostly, I hate (HATE!!!) the way my brakes feel. Hate them. In Moab, going down several steep pitches, I couldn't hold a constant speed. That sucks, and that could be dangerous.

But I was ignoring it up to the point I tried maximum braking. If you have ever known someone who's killed a kid with a car (even though it was not their fault) it is not something you'd wish on anyone except your enemies. I daily drive my rig, and I have to wind my way out through neighborhoods thick with kids.

I can handle being a retard, but I don't want to be a kid killer. You may feel differently...
Click to expand...

Overlander has his ways. :cheesy: but, he’s pointed out one thing that most agree with and that is Terraflex is not a company most of us run for very good reasons.

I am very surprised that you aren’t able to activate your antilock brakes. Personally, i’m 37s with ATX slab bead locks. Probably 120-130 pounds of wheel and tire. I’m only running the Dynatrac progrips front and rear. I lock up and perfectly. In fact, i tested them the other day when some moron decided they needed to make an immediate right turn from the left lane.
 
TheGrendel said:
Overlander has his ways. :cheesy: but, he’s pointed out one thing that most agree with and that is Terraflex is not a company most of us run for very good reasons.

I am very surprised that you aren’t able to activate your antilock brakes. Personally, i’m 37s with ATX slab bead locks. Probably 120-130 pounds of wheel and tire. I’m only running the Dynatrac progrips front and rear. I lock up and perfectly. In fact, i tested them the other day when some moron decided they needed to make an immediate right turn from the left lane.
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I am shocked as well. And that isn't internet chest pounding--I truly can't believe it. I get our rigs stop like aircraft carriers, but still. And I was STANDING on the brake pedal--butt off the seat, worried about breaking the seatback, etc. (and while I am older--late 55's, I do a lot of heavy weight lifting so I am not weak). But pedal was firm, so it isn't an air in the lines thing. And (AND!!!) I have upgraded Hawk brake pads.

Oh, and I asked about Teraflex not because I am a fan, but I am trying to understand why I shouldn't use them.
 
The stock brakes with stock tires is marginal at best. Even worse when adding weight to the vehicle as you have done. The Dynatrac Progrips have proven to work great. I also hated my stock brakes w35s, but when I added the Progrips it stops excellently now. I have much more confidence out on a trail with even larger tires now.

Theoretically, everything you suggested should work better, but I’d recommend sticking with something that’s proven to work for our application. It’s your Jeep, do what you see fit.


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I have, but have not yet installed, the Crown big brake kit. It is basically 1500 4 piston calipers and rotors, with the brackets to locate the calipers.

I will not be able to get them on for a while, but I chose to go that way for the bigger calipers, and the ease of being able to get replacement pads anywhere.

I am going to try just the fronts first, then probably add the rear, same thing, and if needed after that, change the master cylinder.

I went with Crown instead of Terraflex, it seems more like OEM quality.

Nothing against the Dynatrac kit, but I don't want to be stuck with limited availability replacement pads.
 
jdofmemi said:
I have, but have not yet installed, the Crown big brake kit. It is basically 1500 4 piston calipers and rotors, with the brackets to locate the calipers.

I will not be able to get them on for a while, but I chose to go that way for the bigger calipers, and the ease of being able to get replacement pads anywhere.

I am going to try just the fronts first, then probably add the rear, same thing, and if needed after that, change the master cylinder.

I went with Crown instead of Terraflex, it seems more like OEM quality.

Nothing against the Dynatrac kit, but I don't want to be stuck with limited availability replacement pads.
Click to expand...

I may be wrong (and I often am), but the Dynatrac kit just relocates the stock calipers, Meaning you can use any pad (factory or aftermarket) that works with the stock caliper, and there is a wide assortment. Not sure how that is limited availability??? Dynatrac may provide a specific pad, but the caliper hasn't changed, and while Dynatrac's pad may be the best, there are lots of other options.
 
I have ProGrips inbound, due to arrive tomorrow. I chose them mostly due to the recognition here but also ease of install vs braking gains reported.

I’m pretty sure I read somewhere on here that you can use OE style pads in a pinch. In my 30ish years of wrenching on my own vehicles, I haven’t been in a situation where I need pads, right now. [emoji2371]
 
You sound like you have a decent technical knowledge, yes, bigger surface area of rotors and larger calipers (with a matched Master Cylinder) give you more braking force- good thing, but you've skipped over some variables, first off TRACTION if you have it, you will NEVER lock your brakes, if you're running good gripping tires and on decent pavement your brakes should never have to unlock themselves, try some cheapo Chinese tires some time you can skid those on a dragstrip. Next is tire size- 33s on a jk is not that large of a difference from stock, and all the "trimmings" on the jk is a equivalent to a couple fat chicks so you honestly aren't that far out of factory specs to begin with. No ones going to tell you to not get a big brake kit, but your hangup on wanting to be able to lock them is pointless. Im also curious to how much you spent on piecing this together versus the price of the full dynatrac pro grip system that's already a proven better BBK over the other options.

And teraflex makes cheap crappy things for not cheap money, plenty of people run it and don't die.
 
Snboarder113 said:
You sound like you have a decent technical knowledge, yes, bigger surface area of rotors and larger calipers (with a matched Master Cylinder) give you more braking force- good thing, but you've skipped over some variables, first off TRACTION if you have it, you will NEVER lock your brakes, if you're running good gripping tires and on decent pavement your brakes should never have to unlock themselves, try some cheapo Chinese tires some time you can skid those on a dragstrip. Next is tire size- 33s on a jk is not that large of a difference from stock, and all the "trimmings" on the jk is a equivalent to a couple fat chicks so you honestly aren't that far out of factory specs to begin with. No ones going to tell you to not get a big brake kit, but your hangup on wanting to be able to lock them is pointless. Im also curious to how much you spent on piecing this together versus the price of the full dynatrac pro grip system that's already a proven better BBK over the other options.

And teraflex makes cheap crappy things for not cheap money, plenty of people run it and don't die.
Click to expand...

Okay, let me try to respond. First of all, every modern car (and even older ones) can lock their brakes (or activate the antilocks). I think you have something wrong here--I've run slicks on incredibly capable cars on the track--so maximum traction, big power, and 150 mph+ speeds, and the antilock function still worked fine. Me thinks you have some mis-understanding of the antilock brake system, friction physics, traction contact patches on tires, etc. And no disrespect to you (or others) but I want my rig to be able to brake the best that it can, given the tires and weight of the vehicle. If I cannot activate the antilocks (in your terms "lock them"), then my Jeep is not braking to the standard of almost every modern road-going vehicle. Which you (or others) may decide you are okay with--I am not. It is hardly pointless--we are talking emergency braking stopping distances. If you don't care about that I respect your choice, but I do not feel the same.

One direct question. You say the Dynatrac kit is a proven better option. It clearly is not on paper (larger rotor diameter is a plus, different pad compound is an unknown, but no increase in piston surface area is a minus versus other options). Link me ONE head to head comparison. -same vehicle, same day, same road surface, etc and I will throw you total respect. But otherwise you are screaming into the wind.

And as regards Teraflex--I am not a fan boy at all. Just trying to understand if the shade cast here is a price based thing, a price + quality base thing (which is hard to analyze--crappy finish machining is disappointing, but only if you are an form over function dude), or a price + performance thing (which I care greatly about, but so far haven't read, for example, that the Teraflex brake kit has poorly machined caliper piston bores that stick, and therefore decrease braking force). However I am happy to hear that other products suffered from failure or poor performance--I'd actually like some reason to take the Teraflex kit out of contention other than price (and the price bums me out, but my crap brakes bum me out more).
 
64Chevy said:
Okay, let me try to respond. First of all, every modern car (and even older ones) can lock their brakes (or activate the antilocks). I think you have something wrong here--I've run slicks on incredibly capable cars on the track--so maximum traction, big power, and 150 mph+ speeds, and the antilock function still worked fine. Me thinks you have some mis-understanding of the antilock brake system, friction physics, traction contact patches on tires, etc. And no disrespect to you (or others) but I want my rig to be able to brake the best that it can, given the tires and weight of the vehicle. If I cannot activate the antilocks (in your terms "lock them"), then my Jeep is not braking to the standard of almost every modern road-going vehicle. Which you (or others) may decide you are okay with--I am not. It is hardly pointless--we are talking emergency braking stopping distances. If you don't care about that I respect your choice, but I do not feel the same.

One direct question. You say the Dynatrac kit is a proven better option. It clearly is not on paper (larger rotor diameter is a plus, different pad compound is an unknown, but no increase in piston surface area is a minus versus other options). Link me ONE head to head comparison. -same vehicle, same day, same road surface, etc and I will throw you total respect. But otherwise you are screaming into the wind.

And as regards Teraflex--I am not a fan boy at all. Just trying to understand if the shade cast here is a price based thing, a price + quality base thing (which is hard to analyze--crappy finish machining is disappointing, but only if you are an form over function dude), or a price + performance thing (which I care greatly about, but so far haven't read, for example, that the Teraflex brake kit has poorly machined caliper piston bores that stick, and therefore decrease braking force). However I am happy to hear that other products suffered from failure or poor performance--I'd actually like some reason to take the Teraflex kit out of contention other than price (and the price bums me out, but my crap brakes bum me out more).
Click to expand...

You’re the self proclaimed expert here, asking for help, right? Wow! You think TF has a bad rep here because of price? Clearly you haven’t used your massive brain power to adequately search the forum. Have fun with your build.
 
jdofmemi said:
I have, but have not yet installed, the Crown big brake kit. It is basically 1500 4 piston calipers and rotors, with the brackets to locate the calipers.

I will not be able to get them on for a while, but I chose to go that way for the bigger calipers, and the ease of being able to get replacement pads anywhere.

I am going to try just the fronts first, then probably add the rear, same thing, and if needed after that, change the master cylinder.

I went with Crown instead of Terraflex, it seems more like OEM quality.

Nothing against the Dynatrac kit, but I don't want to be stuck with limited availability replacement pads.
Click to expand...


I went with this kit and I can honestly say it is my favorite mod to date. My Jeep stops better now on 37's than it did on factory tires.
 
Dynatrac kit installs in an hour or two. Don't have to bleed brakes. Stops vastly better than stock. Pads last close to the same as stock, or if there's a different pad you want to use, you certainly can. Works awesome in a panic stop situation - I've had to stand on my brakes a couple times. No it didn't lock up, but it didn't need to. Not sure why that's an issue. For me, these reasons are why I went to the Dynatrac kit. I'm sure the Crown kit, Mopar kit, etc etc are fine, I just didn't want to be fucking around in my garage all day long installing calipers and bleeding brakes,
 
Ddays said:
Dynatrac kit installs in an hour or two. Don't have to bleed brakes. Stops vastly better than stock. Pads last close to the same as stock, or if there's a different pad you want to use, you certainly can. Works awesome in a panic stop situation - I've had to stand on my brakes a couple times. No it didn't lock up, but it didn't need to. Not sure why that's an issue. For me, these reasons are why I went to the Dynatrac kit. I'm sure the Crown kit, Mopar kit, etc etc are fine, I just didn't want to be fucking around in my garage all day long installing calipers and bleeding brakes,
Click to expand...

There really wasn't much more time involved with the Crown kit. Only thing I had to do you didn't was move the brake line over and bleed the line. Being the caliper was already compressed there wasn't much air in the line. Maybe five minutes total between the two brakes to get the air out. I think either the Dynatrac kit or Crown kit would be a great upgrade for anyone with larger tires.

I had a huge smile on my face breaking the brakes in. So much better stopping power.
 
Too much thinking on this. If you are having problems braking with a nearly stock JK, you have something fuckered in your braking system and you need to figure that out. I had a noticeable decrease in stopping ability after I put 37's and ATX Slabs on (plus a ton of steel), but I could still lock my brakes and get antilock to kick in. So, on paper, everything you are saying about your braking issues is wrong, yet you are still having that problem. On paper the dynatrac kit doesn't help much in your mind, but when I put the kit on, I almost put my head through the windshield the first time I jammed the brake pedal down, my very heavy jeep on 37s stops about twice as good as stock with the dynatrac kit. Figure out your brake system problem and don't buy the terror-flex gear, just get the dynatrac kit.
 
Sorry

Especially to USMC Wrangler, but to anyone else I may have rubbed the wrong way, I'm sorry. My brakes are worrying me, I am no expert, and I came here seeking advice. To all who have already respond, thank you. I asked for comments, meaning everything was fair game and my skin may have been too thin.

In my track days I changed more pads and rotors, and bled more brakes than I can even remember. Point being is that I am not an expert, but buying an upgrade that requires opening the brake system ain't no thang for me. And I have bought stuff for my Jeep without doing much research--bought it, installed it, and didn't think much about it. So I understand that view too. To me (and maybe to no one else but me)--I am willing to do a deep dive into the brakes, and I want to optimize the performance I get for my dollar.

Regarding Teraflex--I knew there was a general feeling here and I did try to do some background research and find out what the issues (other than price) were. I didn't find it, and was hoping someone could explain--but yep, I will just do more research and try to sort it out.

To any of you who have weighed in, if you are ever in the Pacific Northwest let me know and I will happily buy you a beer as a way of thanks.
 
Torrin said:
Too much thinking on this. If you are having problems braking with a nearly stock JK, you have something fuckered in your braking system and you need to figure that out. I had a noticeable decrease in stopping ability after I put 37's and ATX Slabs on (plus a ton of steel), but I could still lock my brakes and get antilock to kick in. So, on paper, everything you are saying about your braking issues is wrong, yet you are still having that problem. On paper the dynatrac kit doesn't help much in your mind, but when I put the kit on, I almost put my head through the windshield the first time I jammed the brake pedal down, my very heavy jeep on 37s stops about twice as good as stock with the dynatrac kit. Figure out your brake system problem and don't buy the terror-flex gear, just get the dynatrac kit.
Click to expand...

You know, that is a really good point. I don't think anything is wrong, but checking that should be the first thing I do. I'll inspect my brake lines today, and bleed the system sometime over the next week. And, I do think the Dynatrac kit is good (my plan is to use it on the rear) and if a buddy asked what to do (and wasn't big into wrenching on his rig) it would be the clear recommendation (all four wheels). I'll report back...
 
64Chevy said:
You know, that is a really good point. I don't think anything is wrong, but checking that should be the first thing I do. I'll inspect my brake lines today, and bleed the system sometime over the next week. And, I do think the Dynatrac kit is good (my plan is to use it on the rear) and if a buddy asked what to do (and wasn't big into wrenching on his rig) it would be the clear recommendation (all four wheels). I'll report back...
Click to expand...

Yup, that is the best thing to do. The dynatrac kit will solve a lot of braking problems, but not if you have air in your system or a failing/leaking component. I would also do a inspection for fluid sitting anywhere in the system. a small pinhole could cause loss of power without dumping a ton of fluid. Braking on the JK sucks stock, but hard braking should produce enough stopping power to engage the antilocks so there is something else going on.
 
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