Front Brake Rotor Size.

[Wiz.au]

A question for all, particularly those who take their wheels off and do their own brake services. I'm about to do rotors and pads, front and rear (don't ask why, partly just cause I want to put flashy new rotors on with my new '4WD' Ceramic & Carbon pads)

In my perusal of the various parts available, I came across some data in the TRW Catalogue. It states that:"Vehicles with HD suspension, use 332mm Front Rotor." The standard rotor on my car is apparently only 302mm

Hmm, like WTF is THAT!
What KK Cherokee got "HD Suspension", and how come they get a 332mm Front Brake Rotor?

But the big question.... CAN I GET THAT??
Having worked in the industry I'm betting it's the same brake caliper, and just a different caliper to wheel hub bracket, to accommodate the larger 332mm Rotor.

The first thing is that for the larger diameter rotor, do the 17in wheels fit? That might help me work out what KK got this "HD Suspension" kit, as they might have 18, or even 20in wheels? I dunno, I gotta do some measuring there, but it's only 15mm (half of the 30mm difference).

I'd love to check some form of Mopar parts fiche for the Caliper Brackets and see if there are different part numbers, to do an easy 330mm rotor upgrade! Just get the new brackets and the 330mm rotors, and 'doneski', instant brake upgrade.

I did a similar thing on my Commodore when one day while working at the brake shop, I discovered that Corvette calipers and hubs (rotors) would fit my Commodore. Instant ventilated and alloy finned caliper upgrade! Yeah! That thing would put you through the windscreen when you jumped on the anchors after that.

I shouldn't have to worry about the ABS stuff either, as the ABS rings are integral to the wheel bearing hub, and are not 'in the mix' as such. I won't have to worry about brake lines as the lines for the 330mm setup will be shorter if anything, so my hoses will end up having 15mm 'slack' in them. No issue at all.

So, anyone got any info they can share about this?
Anyone with a Sport willing to measure their front rotors for me?

[Wiz.au]

Thanks to Ted15 on the JeepForums, we have the following information:

Option Code 'BRY' is the 302mm 'Standard' setup
Bracket 68003699AA
Pin kit 68003706AA
Caliper right 68003697AA
Caliper left 68003707AA
Rotor 52109938AB
Pads 68003701AA

Option Code BR6 is the 332mm 'HD Brakes' setup
Bracket 68044865AA
Pin kit 68049018AA
Caliper right 68044864AA
Caliper left 68044862AA
Rotor 04779599AB
Pads 68044866AC

Bugger, the calipers are apparently different. The pads could just be a formulation, because every brake pad option I looked up had no mention of "HD Brakes", but when I cross ref the Mopar part numbers with Brembo, I get different Brembo numbers. The HD brake pads are 1mm thicker, (19mm vs 18mm) for a start. Errg.

[Wiz.au]

OK, I think I'm stuffed. My build code for the brakes is "BRY", so I have confirmed I have the standard 302mm brakes.

And others have said that the upgrade may need minimum 17in wheels, so I would render my 16in off-road steel wheels with mud tyres useless to me. Bugger!

However I have found that the 'standard' upgrade according to the Dodge Nitro forums is:

• TWIN METAL PISTON (I didn't know our pistons are composite - PLASTIC!) 'RAM 1500 Calipers' (which are NOT the calipers fitted in the KK's BR6 'HD' kit),
• the Caliper Bracket from the JK Wrangler 'Big Brake Upgrade' Kit ('BBK'), and,
• the 332mm KK 'HD' (BR6 option) rotors

The best commercial option is advised as the Crown RT31046 Kit for the Wrangler:
https://www.crownautomotive.net/HD-P...t/RT31046.html and toss the Wrangler rotors as the kit with rotors is cheaper than the individual parts without the rotors. Then get any BR6 'HD' option rotors from any parts supplier.

Nitro owners also have to upgrade the Brake Booster and Master Cylinder. I'm unsure if we (KK Owners) already have these fitted as standard, or if the posts referring to "Jeeps" and "Mopar" already having the larger MC & BB actually mean "Wrangler", not the "Liberty/Cherokee".

I've got a set of new brake pads to use before I think about this again, and maybe a set of wheels & mud tyres to change along the way! But I definitely see it in my future!

[davod8]

The Jet model atleast comes with the 332mm rotor and the pads are the same for either rotor.
I had to measure mine before ordering.

[Wiz.au]

Thanks for that it really helps knowing that parts from a wrecked Jet will get me the BR6 upgrade. Just wish I could find the part details for the JK bracket for the RAM 1500 Calipers so I don't have to import the whole Crown kit. Then I might be able to source all the heavy & expensive parts domestically and save the huge freight costs being quoted for the kit @USD$500!

[Wiz.au]

Originally Posted by davod8

The Jet model atleast comes with the 332mm rotor and the pads are the same for either rotor.
I had to measure mine before ordering.

That doesn't quite match up with my research.
The Pads are different Mopar Part Numbers;


And the Brembo part numbers are different too, P11022 vs P11025, and the BR6 part number is 19mm thick, vs only 18mm thick for the BRY part. They do both have the same 147x63mm dimension, but I have yet to find an image to compare the shape. By the very definition of being a 30mm larger rotor, the circumference should be 'straighter' on the BR6 vs the BRY. The BRY pads might fit in the BR6 caliper, but they are not 'right'. BRY pads would be curved ever so slightly more than BR6 pads.

OK, according to Brembo, I'm 'wrong'.
The pads use the same dimensions backing plate, [Code 24604 for both the P11022 & P11025 pads] but the pad material is 1mm thicker on the P11025 [BR6] part. So P11025 [BRY] pads will fit the BR6 calipers, but you're short changing yourself 1mm of extra material that the BR6 Calipers can take.

However, taking that information, plus the fact the Caliper Piston & Seal kit is the same for both the BRY & BR6 calipers, leads me to understand that the BR6 caliper is the same in volumetric fluid and piston cross sectional force, so is THE SAME clamping force as the BRY caliper. The only difference is that the BR6 caliper can take a set of pads with 2mm more material!

So... given that.... All I need is the BR6 Caliper bracket and some 332mm BR6 Rotors, and I am just limited to BRY 18mm thickness pads in my BRY Calipers. EASY! And just as I thought. It's pretty much the same caliper, it can just take thicker pads. I am, however, assuming the BR6 bracket bolts onto the BRY caliper and the slide pins match up. I will only be able to do that when I have a bracket in my hands.

Just thinking some more on that, I'll bet that's why the slide pins are different on the BR6 caliper,... To allow for the extra movement of the thicker pads. Or it could be they are a larger diameter to take the extra force of the larger diameter rotor? I might have to get one of those in my hands too.

Time to find a wrecked 2012 Jet KK!

[Jeep GC]

Nice find!

Please post back if you do the bigger disc upgrade and what was needed parts and number wise. I'll file that away for future use.

I'm slapping on new rear disc and pads this Australia Day with looking at front rotors and pads when due, maybe this time next year for the fronts.

If I can swap out to Jet rotors/calipers/pads on the front, cool. Maybe a few pics too