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Successor to the "HD12" Brake Upgrade

5.9K views 57 replies 11 participants last post by  GoremanX  
#1 · (Edited)
January 15th, 2025: added a MUCH more affordable cast iron hub option which saves $249 over the cost of the expensive billet aluminum hubs.

HD12 Brake Upgrade Successor

One of the best front brake upgrades for these cars was developed and provided by @Navy Lifer in the form of his HD12 kit. This was the ultimate in bolt-on convenience for upgraded brakes that stop hard, resist fade, fit in all OEM wheels, and use easily-obtainable service parts. It was pretty cost-effective, too, and easily-reversible to return to stock. Sadly, he ran out of inventory for the brake rotors.

After much research, I've come up with a list of part numbers that allow anyone to replicate the HD12 brake kit. This retains all the benefits of the original kit, but using readily-available rotors and hats in place of the previous one-off rotors and KORE3 hats. I'll list and describe the kit part numbers below, as well as possible add-ons that are worth considering. (I'm not affiliated with Wilwood or KORE3 in any way, I just happily use their products that I purchased at no discount whatsoever)

Core Kit (with cast iron hubs)
  • Aluminum hats: Wilwood 170-0357 (need 2)
  • Rotors: Coleman Racing - ask for a "Frank Gore" brake rotor set, either "RACE" or "STREET", call Coleman Racing at 1-866-COLEMAN, see more info below
  • Hardware: Wilwood 230-12120 (need 1)
  • Cast iron hubs: RPM Automotive Brakes Hub Kit (need 1)
  • OEM calipers for a 1994 to 1996 Cadillac Fleetwood commercial chassis (option J55): OEM part numbers 18005246 for right, 18005245 for left

Core Kit (with billet aluminum hubs)
  • Aluminum hats: Wilwood 170-0764 (need 2)
  • Rotors: Coleman Racing - ask for a "Frank Gore" brake rotor set, either "RACE" or "STREET", call Coleman Racing at 1-866-COLEMAN, see more info below
  • Hardware: Wilwood 230-12120 (need 1)
  • Billet aluminum hubs: KORE3 GMTS HD (need 1)
  • OEM calipers for a 1994 to 1996 Cadillac Fleetwood commercial chassis (option J55): OEM part numbers 18005246 for right, 18005245 for left
The differences between the HD12 kit and the above list is that the rotors are balanced (and optionally slotted and stress relieved for the RACE rotors). They have the same directional venting and the same or better thermal capacity. The hats will slide right on without any hub ring required.

The kit with cast iron hubs adds 1/8" of track width (each front wheel gets spaced outward by 1/16"). Those hubs cost $300, which is $249 less than the billet aluminum hubs. They also come with ABS tone rings pre-installed.

The kit with billet aluminum hubs reduces the front track width by a negligible amount, less than 1mm or "0.030. May as well consider it OEM track width. If you want to retain the ABS functionality, you still need to pull the ABS tone rings from the old OEM brake rotors and install them onto the KORE3 hubs. I was able to easily remove the old tone rings with a standard 3-jaw puller, a little heat applied to the tone rings can help them pull off smoothly without breaking.

Note that the part number for rotor hats is different between the two configurations. The cast iron hubs require hats that have a deeper offset. Both part numbers cost the same (currently $101 per hat).

The calipers are readily available at most auto parts stores or on Rock Auto from many different brands (including AC Delco) in both reman and new for very affordable prices.

Pair the kit with your favorite D52 brake pads (any pads that would've fit in your original calipers) and you'll be all set. There's other threads on this forum that have recommendations for adequate pads to suit anyone's needs.

Options and Add-Ons

Brake Rotors
Coleman Racing will make rotors of most shapes and sizes. After some trial and error, I've come up with rotor specs that fit perfectly and allow any thickness of brake pad. Simply call Coleman Racing and tell them you want to order a set of Frank Gore brake rotors. The two choices are RACE or STREET;
RACE - For heavy duty applications to help prevent cracking from extreme heat. HD casting (thicker face), slotted, balanced, stress relieved via heat treatment, directional vents, $394.24 for the pair at current prices.
STREET - If you don't plan to race your car, save a few bucks over the race rotor. Standard casting (same face thickness as stock), plain face, balanced, directional vents, about $280 per pair at current prices.

Wilwood Calipers
In place of the OEM calipers listed above, you can also opt for Wilwood forged billet aluminum dual-piston calipers that will bolt right on. The part number for that is 120-10936 (available in gray, black or red, need 2 because they're interchangeable L/R). Those calipers require a 7/16-20 banjo bolt that's larger than the stock M10, so new front matching flex lines will be needed as well. Note that the stock brake fittings on the hard lines are M10-1.0 bubble flare. A combination of Fragola 352012 hoses and 650205 fittings would combine to make the correct flex line. Technically the dual 2" pistons have slightly less surface area than the huge single piston on OEM calipers, but the reduced flex of the caliper construction and the more even pressure applied to the pad means that they end up providing about the same braking effort as the OEM calipers. Only pads with a smooth backing plate will work (no shim rivets), and you can't use the retaining clip on the inside pad, so it might end up rattling around while not applying the brakes. This is not a safety or performance issue, just a potential annoyance. These calipers do look very pretty. They also might not fit in some OEM 15" wheels.

Solid Bearing Spacer
The factory-original method to mount the hub is to tighten the spindle nut to 12 ft-lb while turning the rotor (to seat the bearings directly against the races), then loosen the nut, re-tighten the nut by hand, and back it off to the closest cotter pin hole. This is intended to provide a bearing clearance of 0.001" to 0.005". However by using a solid bearing spacer, you can not only target a specific bearing clearance (ideally exactly 0.001"), you can also ensure that the bearing shells will never spin against the spindle. There's also speculation that pre-loading the spindle with the nut helps to stiffen it up. All of this provides noticeably more precise steering, longer bearing life, cooler-running hubs, and more predictable braking. Having the bearings with a 0.001" clearance helps prevent pad knock-back, so the brakes will be more likely to grab when you expect them to. Setting it up takes a bit more time and effort than a standard installation. KORE3 sells a bearing spacer kit that you can call and ask for. More recently, PTFB started selling a similar kit for less money that basically does the same thing. It can be found here: Wheel bearing spacers | Pro Touring FBody (I'm not affiliated with PTFB in any way, and I'm not promoting their product over the KORE3 product in any respect other than potential price, I've never used the PTFB bearing spacer. I have 2 sets of KORE3 bearing spacers that I love)

Stainless steel braided hoses
I don't think I need to describe these too much, everyone knows about them. They're available from many sellers and manufacturers. They'll improve the feel of the pedal by reducing flex in the system. They will not increase the amount of total braking force, though they may reduce the amount of pedal pressure needed to achieve the desired braking force, and they'll improve feedback through the pedal so you can better tell what the tires are doing.

Edit history:

5/19/25 - updated the rotor hat part number for the core kit from 170-0208 to 170-0357 after actually measuring the cast iron hub to confirm that its face has actually been machined down. Updated the effect on track width from 1/2" to 1/8" as a result. Updated the Wilwood caliper info to reflect the need for new lines in addition to banjo bolts.

4/11/25 - updated the hardware part number from 230-12020 to 230-12120 (original was a typo).
 
#3 ·
What's the approximate cost of these upgrades? (Yeah, sorry, I'm being lazy instead of looking up the parts.)
 
#5 ·
Sherlock9c1's Astro rotor brake upgrade would be way less money. And going by published and measured weights they have more mass. Astro run about 19 lbs, the Wilwood are 13ish. Not sure the aluminum hats offer enough cooling vs the added mass of the Astros.
 
#10 ·
I did the weighing with my HD12 kit way back when I had all the bits uninstalled. Ultimately, the HD12 components (KORE3 hubs, hats, rotors, J55 calipers) ended up weighing slightly less than a stock B-body brake rotor with stock caliper. So the rotating and unsprung mass is less (by about 3 oz), but the part of the rotor that actually generates and dissipates heat has more mass and can get rid of it much more efficiently due to the directional vanes. There's no doubt that the HD12 kit resists fade much better than stock brakes, that's been proven again and again over the years.

The equivalent Wilwood components (if they actually fit together) are listed at identical weights to the original HD12 components.

I don't know what the cut-down Astro rotor setup weighs.
 
#6 ·
I own some Wilwood hats , used them on my front drag brakes.
I have used them on other projects

E-COAT , they say it like it is some magical coating.
Acts like normal paint
Scratches off
Brake fluid attacks it.
Likely will mask cracks ?

Not impressed.

Next time they are off they will get anodized methinks.
 
#7 · (Edited)
Keeping in mind that this is all a moot point until Wilwood can confirm some stuff to me (I'm still in contact with them):

A TCE 13" big brake kit starts at $2050, and as far as I know, it doesn't add any thickness to the rotors. They're still only 1" thick. So thermal capacity (which is what really matters here) is less than the HD12 kit. What I listed above adds up to about $1300 using Fleetwood calipers.

All the other options other than HD12 can't be run inside 15" wheels. That was literally always the point of the HD12 brake kit, a significant upgrade in braking capacity that will bolt right on and fit inside stock 15" wheels. Nobody ever claimed it was the best or cheapest option. But there's enough of those kits that have been installed to attest to the fact that the upgrade works extremely well.

I've also got a few Wilwood hats, the finish on mine seems very similar to my KORE3 hats. My understanding has always been that aluminum hats should not be sprayed with brake cleaner. I was warned about that again when I bought the original HD12 kit, which included KORE3 aluminum hats. I find this stipulation annoying, how's anyone supposed to clean brake rotors without getting brake cleaner on the hats? And what about billet aluminum hubs? Do those have to avoid brake cleaner? 🤷
 
#8 · (Edited)
This from a different forum.
I'm just quoting
"
The MSDS from CRC actually says avoid contact with aluminum and other metal POWDERS. Powdered aluminum would have a high surface are which would give a high concentration of aluminum oxide, which, apparently, can cause the tetrachloroethylene to decompose, releasing nasty chlorine.

Thing, now days , there are so many types and formulas it is hard to know.

They have some stuff upstairs , Motorcraft metal brake parts cleaner , stuff reeks like carb cleaner , I would be afraid to get it on rubber brake parts I cared about.

Hot soapy water and a soft bristle brush on my brembo calipers here.

Not like the good old days.
Carbon tetrachloride
Everything was clean , nothing caught fire and a laundry list of serious to deadly health effects
 
#12 ·
Here is the thread that I ended up starting. The opening post contains a bunch of fun facts:


Then here is a post from me in a different thread:

 
#13 · (Edited)
I updated the original post with information on the rotors. These new rotors are less expensive than the Wilwoods I originally planned on, and include more features. Plus there's an option for a race or street version to cater to different needs and budgets.

The only major expense remaining is those KORE3 billet hubs. I wish there was a less expensive alternative, they've gone up by $140 in the last few years (they cost $409 back when I first bought them). There are other, much more affordable 5x5 billet hubs available on the market, but they're not designed to accept an ABS tone ring :rolleyes:
 
#15 ·
One of the best front brake upgrades for these cars was developed and provided by @Navy Lifer in the form of his HD12 kit. This was the ultimate in bolt-on convenience for upgraded brakes that stop hard, resist fade, fit in all OEM wheels, and use easily-obtainable service parts. It was pretty cost-effective, too, and easily-reversible to return to stock. Sadly, he ran out of inventory for the brake rotors.

After much research, I've come up with a list of part numbers that allow anyone to replicate the HD12 brake kit. This retains all the benefits of the original kit, but using readily-available rotors and hats in place of the previous one-off rotors and KORE3 hats. I'll list and describe the kit part numbers below, as well as possible add-ons that are worth considering. (I'm not affiliated with Wilwood or KORE3 in any way, I just happily use their products that I purchased at no discount whatsoever)

Core Kit

  • Aluminum hats: Wilwood 170-0764 (need 2)
  • Rotors: Coleman Racing - ask for a "Frank Gore" brake rotor set, either "RACE" or "STREET", call Coleman Racing at 1-866-COLEMAN, see more info below
  • Hardware: Wilwood 230-12020 (need 1)
  • Billet aluminum hubs: KORE3 GMTS HD (need 1)
  • OEM calipers for a 1994 to 1996 Cadillac Fleetwood commercial chassis (option J55): OEM part numbers 18005246 for right, 18005245 for left
The differences between the HD12 kit and the above list is that the rotors are balanced (and optionally slotted and stress relieved for the RACE rotors). They have the same directional venting and the same or better thermal capacity. The hats will slide right on without any hub ring required. They're the same thickness as the ones that were included in the HD12 kit, so the same track width is retained. If you want to retain the ABS functionality, you still need to pull the ABS tone rings from the old OEM brake rotors and install them onto the KORE3 hubs. I was able to easily remove the old tone rings with a standard 3-jaw puller, a little heat applied to the tone rings can help them pull off smoothly without breaking.

The calipers are readily available at most auto parts stores or on Rock Auto from many different brands (including AC Delco) in both reman and new for very affordable prices.

Pair the kit with your favorite D52 brake pads (any pads that would've fit in your original calipers) and you'll be all set. There's other threads on this forum that have recommendations for adequate pads to suit anyone's needs.

Options and Add-Ons

Brake Rotors
Coleman Racing will make rotors of most shapes and sizes. After some trial and error, I've come up with rotor specs that fit perfectly and allow any thickness of brake pad. Simply call Coleman Racing and tell them you want to order a set of Frank Gore brake rotors. The two choices are RACE or STREET;
RACE - For heavy duty applications to help prevent cracking from extreme heat. HD casting (thicker face), slotted, balanced, stress relieved via heat treatment, directional vents, $394.24 for the pair at current prices.
STREET - If you don't plan to race your car, save a few bucks over the race rotor. Standard casting (same face thickness as stock), plain face, balanced, directional vents, about $280 per pair at current prices.

Wilwood Calipers
In place of the OEM calipers listed above, you can also opt for Wilwood forged billet aluminum dual-piston calipers that will bolt right on. The part number for that is 120-10936 (available in gray, black or red, need 2 because they're interchangeable L/R). Those calipers require a different banjo bolt. Technically the dual 2" pistons have slightly less surface area than the huge single piston on OEM calipers, but the reduced flex of the caliper construction and the more even pressure applied to the pad means that they end up providing the same braking force as the OEM calipers. Only pads with a smooth backing plate will work (no shim rivets), and you can't use the retaining clip on the inside pad, so it might end up rattling around while not applying the brakes. This is not a safety or performance issue, just a potential annoyance. These calipers do look very pretty. They also might not fit in some OEM 15" wheels.

Solid Bearing Spacer
The factory-original method to mount the hub is to tighten the spindle nut to 12 ft-lb while turning the rotor (to seat the bearings directly against the races), then loosen the nut, re-tighten the nut by hand, and back it off to the closest cotter pin hole. This is intended to provide a bearing clearance of 0.001" to 0.005". However by using a solid bearing spacer, you can not only target a specific bearing clearance (ideally exactly 0.001"), you can also ensure that the bearing shells will never spin against the spindle. There's also speculation that pre-loading the spindle with the nut helps to stiffen it up. All of this provides noticeably more precise steering, longer bearing life, cooler-running hubs, and more predictable braking. Having the bearings with a 0.001" clearance helps prevent pad knock-back, so the brakes will be more likely to grab when you expect them to. Setting it up takes a bit more time and effort than a standard installation. KORE3 sells a bearing spacer kit that you can call and ask for. More recently, PTFB started selling a similar kit for less money that basically does the same thing. It can be found here: Wheel bearing spacers | Pro Touring FBody (I'm not affiliated with PTFB in any way, and I'm not promoting their product over the KORE3 product in any respect other than potential price, I've never used the PTFB bearing spacer. I have 2 sets of KORE3 bearing spacers that I love)

Stainless steel braided hoses
I don't think I need to describe these too much, everyone knows about them. They're available from many sellers and manufacturers. They'll improve the feel of the pedal by reducing flex in the system. They will not increase the amount of total braking force, though they may reduce the amount of pedal pressure needed to achieve the desired braking force, and they'll improve feedback through the pedal so you can better tell what the tires are doing.
Hub kit 5 on 5" 92-96 B-body Brake Swap 5th Gen Camaro Brembo conversion | eBay how about these hubs?
 
#16 ·
Those look VERY promising... they use the correct bearings and seals. They even use the correct ABS reluctor. I guess the important thing is the flange offset. What rotor hat thickness do they require to maintain the proper track width? That dictates which rotor hats will work with stock calipers since not all hat offsets are available in all hat thickness. I have no way of confirming that short of buying a set, which I might do just because they look so promising.
 
#19 · (Edited)
I know that seller - Jason Hurst, he's a great guy, tremendous machinist, and loves brakes. He's actually a paraplegic - was injured and broke his back awhile back. He had a Cadillac Fleetwood, a box Caprice, and now has an S10 Extreme with a gen2 LT4 swap (The S10 extended cab is far more convenient for his wheelchair). He is a brake guru; can pretty much make you any brake setup you want.
 
#20 ·
Well those hubs look downright perfect, and they're a VERY reasonable price. Building a front brake setup with those hubs, Coleman Racing rotors and Wilwood hats, a complete, bolt-on wide brake setup could cost as little as $1000 all-in (assuming "street" rotors, cast iron calipers, readily available pads, and traditionally-mounted bearings). That's pretty fantastic.

I don't think even non-ABS hubs would be more affordable.
 
#22 ·
Aren't those " just" some rotors the seller cut the rotor off ?
They are cast iron, I am pretty sure he doesn't have a foundry up and running.
That could be, in which case the flange offset would be wrong by 1/2" (for a total of 1" for both sides). So it would require a rotor hat that has an extra 1/2" offset. I'm waiting for the seller to get back to me.
 
#24 ·
Also, the wheel mounting hub looks machined differently. I'm wondering if he also machines the flange down to account for the presence of a rotor hat. Considering the machining work involved, $300 is pretty decent for the pair. If the flange offset is correct, it could be a great "budget" option over the KORE3 hubs.
 
#25 ·
I get not everyone has the tools .

I FORGET people are doing this to make a profit, and not work for the 5 dollars an hour I seem to generate when helping people

Please note , the parts I listed was just some random search.
 
#26 ·
Oh I thought it was a totally valid observation. I mean, cast iron kinda negates some of the unsprung weight savings. But yeah, my big roadblock to including "stock hubs with rotors cut off" as an option is that very few DIY'ers have easy access to the tools needed to accomplish that. I've been perusing Facebook Marketplace for over a year hoping to find a brake lathe at a reasonable price in my area, and I keep not succeeding. And my local machine shop charges an arm and a leg for super simple jobs, so I tend not to go there.
 
#27 ·
Random side note - Jeep Grand Cherokee Trackhawks (with the SRT hellcat motor) have large rotors with a 5x5 bolt pattern. Way too big for a 15" or even an Impala SS 17" wheel though.
 
#28 · (Edited)
I just updated the original post to include information on cast iron hubs that are much more affordable than the KORE3 billet aluminum hubs.

Currently, prices for putting together a complete would look like this:

Cast iron hubs with street rotors
2x hats = $202
1x rotor set = $280
1x hardware set = $25
2x J55 calipers = $40 (at RockAuto)
1x pads = $30 (at RockAuto)
1x hub set = $300

Total = $877
(does not take into account shipping costs, taxes, or refundable core charges)

That's pretty darn decent for fade-free brakes that will fit inside any OEM 15" wheels. From there, you can tune the cost to match the desired performance with the optional upgrades listed.

I can attest to this; the race rotors on billet aluminum hubs are unstoppable. With affordable Performance Friction pads, I can lock up the front brakes anytime by pressing hard enough on the pedal, I get excellent modulation, and the brakes never fade. With Wilwood BP20 pads, the initial bite is stronger, but all the rest of the characteristics remain (with added squealing and dusting, as expected). I'm never going back to stock brakes.
 
#29 · (Edited)
Just to clarify a bit here:

All TCE kits since day one have been 13 x 1.25" never once have I provided a 1" rotor. There have also been some 1.375" wide rotors provided for guys who ran open track days with the cars. I might point out also that this goes back to 1997. I hear from one of my first customers from time to time who (with some 300K miles on the car) still is happy with his purchase. I think he's replaced rotors a couple of times.

The original and standard stuff for the SS today is still a custom Coleman rotor and will remain that way for some time. The reason is matching to the rear kit- everyone likes a matchy-matchy look. We do now offer a front kit that could be used on the SS with an off the shelf Wilwood (not Wildwood) part. That's great for saving a few bucks on 'rings' but I get negative feedback when they are paired with our custom rear rotor for visual reasons. All of that could be changed a bit in the future. But really; why complicate a good thing? And they've all been tried and proven to be very effective on both the street and open track. Our standard 'ring' for that kit today will run you about $250ea from me or from Coleman (D&S). The 13" Wilwood rotor (D&S) runs about $330ea. But replacements, when properly cared for, are very few and far between.

There are a few reasons to retain the TCE standard: first is keeping it consistent. All TCE kits fit the stock wheels. The "optional" format won't do that if I recall. Also back when we began this build a 13" rotor was unheard of and some parts used were what was on the market for 11.75 and 12.2 rotors at that time. Far more popular. For that reason the hats, their spec, the brackets and calipers are almost identical to the first kits. Now some 1000 units deep in sales.

Another change is the move to larger kits. Let's be honest here....not a lot of guys today keep the stock 17" wheel. We dabbled a bit in 14" kits for 18" wheels. But that wheel market (like 16s) didn't stick around long. Today is 13" for stock, 15 and 16" kit for the primary market. Seldom much demand for 14 but I'd do one custom if so desired. The few we did were BSL6 parts and that's just not the real deal, today it would be an Aerolite model.

Cost? Today it's Black or Red with drilled and slotted rotors for $2049 plus shipping- and all those items you're looking at are included by default. Thinking back now some 25+ years I think it was abou $1400. And more for D&S. Powder coat was not even a thing! lol I think we've done a pretty damn good job on costing this today. The calipers are better, the pads are better, color is standard, zinc plated D&S rotor by default.....It's all a better value Today than it was Then really.

I have nothing against those who may be trying to redesign the wheel here....people can poor over options and figure out what might work and how. Or you can just bite the bullet and drive it completed in a week and forget about all the what-ifs.

TC

*Corrected rotor prices to both be drilled and slotted.
**Slotted only rotors are also an option.
 
#30 ·
Just to clarify a bit here:

All TCE kits since day one have been 13 x 1.25" never once have I provided a 1" rotor.
Thank you for that clarification! I thought I had looked it up on the site before posting that those rotors were 13"x1", but I must not have looked very hard because it's clearly stated there.

Not dismissing TCE brakes at all, those are some serious kits. This is just intended as an upgrade that bolts on quickly, doesn't change front/rear bias, and fits in stock 15" wheels. Exactly the same spirit as NavyLifer's original concept from a decade or so ago.

Sorry about that one misspelling that my phone introduced when I swiped "Wilwood" 🙄
 
#35 · (Edited)
For those frustrated the excellent HD12 kits are no longer available, recently I have been working on an alternate way to mount common C3 12”x1.25” rotors, combined with off the shelf pads, common Timken bearings and OEM hub seals for our cars at a reasonably sane total cost.
Rekudo is offering a range of options that solves several important concerns simultaneously.

1 inch taller chromoly spindle uprights @ $385/pr., ‘one-inch-drop’ spindle location, C3 4140 billet hubs @ $220 ea., forged 7075 4-piston JL8 calipers @ ~$870/pr., off the shelf rotors, pads, bearings, seals, 1.820”x4 pistons. One thing is that these calipers functionally replicate the old rust-prone Delco Morraine cast iron calipers for this application, but Holley (who now owns Rekudo) claims that the mounting ears are C5/C6 Vette, which means multiple larger superior rotor and caliper options may coexist on the same upright. I would like to have that assertion validated by Rekudo directly. But still, if all the Rekudo stuff is combined you can get better suspension geometry, handling, braking performance, looks like a win/win.

Still trying to figure out an equivalent compatible matching rear disc setup for my 1995 RMW, thinking that it seems to be similar to 1980s era C-10/20 pickups in the rear regarding backing plate bolt pattern and flange offset.

Just requires the 4.75” BC up front, but then 15x8” Vette wheels fit perfectly, and so do a multitude of other muscle car wheels will also work.
Over 40 years ago I figured out how to mount 12”x1.250” Coleman discs on modified iron hubs to use the JL9 truck calipers with their 3 5/32” pistons, but every part was custom made, I couldn’t even afford standard NASCAR brake components at the time, I got tired of adapting and custom fabricating every part every time.