[Kolak]

High quality drilled rotors, such as the Stillens that I've sold for many years, will give you additional cooling and clamping power. That will be very appreciated in mountainous terrain or during hard stops.

Stillen uses only the highest quality one piece cast (not composite) rotor blanks. Their drill patterns are optimized for best performance without creating rotor stress. The holes are both radiused and chamfered to prevent cracks. Stillen does all drilling and final surfacing in their facility in southern CA.

I have them on special right now at an excellent price - PM me your email address for all the information.

Originally Posted by kc2mrg

well let me as a somewhat different question, i do like the black magic brake swap, and im thinking about doing it to my 04, but is there any advantage to getting drilled rotors? or is that what the black magic kit comes with? id prefer to sway away from slotted since ive been told the slotted just takes life off the pad by cutting off a small layer of pad every time you hit the brakes. also i do plan to do some wheeling with my jeep, i dont want to cause more issues for myself

[leadsled jeep]

Thanks for mine Nick. They arrived this week and I look forward to the improvements. I also like the black coating which should keep rust at bay I assume?

[billzcat1]

Drilled rotors are more for looks in my opinion - the major issues with pad outgassing (that drilled rotors were designed to address) have been solved with modern pad components. They increase noise and reduce service life, although they do help cooling very slightly. Even some of the higher quality drilled rotors are susceptible to warping and cracking around the drilled holes. The cheap ones? Forgeddaboudit! Run whichever you prefer, but you really aren't getting much from drilling. When you use good enough pads, it's pretty much impossible to overheat the system anyway.

If you want drilled, definitely get the Stillen ones from Kolak, they are about the nicest you can buy. I can't recall anyone having cracking issues with them. If you want plain, get Centric. I found them to be exceptional rotors for the price - epoxy coated on every non-wear surface, including all the way down the vanes. Also, perfectly balanced and zero runout. Even the cross-hatch milling on the friction surface (for better break-in) was nicely done.

[Kolak]

I sort of cringe when I hear that drilled rotors are just for looks. My 18 years of experience with Stillen rotors and 16 years of selling them commercially gives me a very large database of both personal results and feedback from my customers. It's also worth noting that I currently have numerous customers that are still running the same set of Stillen rotors for 5+ years so they also have excellent longevity.

Nevertheless, I posted the summary of the SAE report on drilled rotors in another thread. It was done on street-driven vehicles and the conclusions are that properly drilled rotors enhance cooling and stopping power. I'll find that summary and post it here in a minute.

[Kolak]

The Society of Automotive Engineers did an extensive study of cross-drilled vs plain rotors on street-driven vehicles back a few years ago. This is the report summary:


Conclusions:

1: Effect of Crossdrilling on Brake Cooling

90 hole crossdrill pattern on the front of system 1 improved heat rejection capability of the rotor between 8.8% and 20.1% depending on vehicle speed. A 64 hole crossdrill added to the rear improved heat rejection of the rear by 3.2% - 8.5%. This was confirmed in system 2 and improved heat rejection through the entire speed range of 50 kph to 140 kph.

These results are consistent with the theory that rotor crossdrilling can increase heat rejection capability of the brake rotor by improving airflow through the vent area of the rotor but it is possible to divert too much of the airflow through the vent area to the crossdrill holes than to the outer edge of the rotor, depending on rotor vane type.

2 and 3: Effect of Crossdrilling on Brake Output and Wet Braking

Both systems 1 and 2 exhibited higher brake system output in high temperature, high brake pressure conditions with crossdrilled rotors than with non-crossdrilled rotors. System 3 employed NAO (non-asbestos organic) pads and did not benefit from crossdrilling.

This supports the theory that crossdrilling provides macroscopic mechanical interface between the pad and rotor to improve braking and resist brake fade.

4: Effect of Crossdrilling on High Temperature Pedal Feel

High speed fade testing resulted in lower pedal travel to a target vehicle deceleration with crossdrilled rotors. Less apply system runout was noted with the crossdrilled rotor configurations. This was due to brake system output with the crossdrilled rotors being high enough versus output with the non-crossdrilled rotors to reduce operating pressure. Less taxing on the master cylinder and vacuum brake booster on the apply.

5: Effect of crossdrilling on lining wear

Depending on configuration of the brake system, there can be little difference in lining wear but the largest difference occurs and higher temperatures where the lining softens and can be extruded into the crossdrilling holes. High temperature conditions also proved to wear linings faster on the non-crossdrilled rotors.

6: Other effects

Whirring noise under certain conditions. Risk of crevice corrosion. Holes can collect wear and road debris. Possible reduction of rotor fatigue life. Reduced risk of pad friction surface glazing and reduced judder mechanisms.
__________________
Kolak Performance and Offroad

[lestatsghost]

Originally Posted by billzcat1

When you use good enough pads, it's pretty much impossible to overheat the system anyway.

I would have to disagree with this especially if you live in or drive I-70 in Colorado. You can see at least one of any vehicle fry their linings traveling down a 6% grade on any given day and that includes corvettes with the carbon fiber brake pads and disks. Some people just don't realize you need to down shift even an automatic when going down a hill for miles rather than use your brakes. The smell is horrible when brakes are over heated too. It is unlikely for most to destroy their brakes in most parts of the country but really easy here in Colorado if you don't know how to control a vehicle on miles of 6% grade.

[billzcat1]

Kolak - I'd like to read that paper to see what the testing conditions were.

I don't dispute that those are all possible improvements that can be seen. I've used cross-drilled, slotted, orbital slotted, slotted + dimpled, and drilled + slotted rotors. I have never noticed any improvements in braking performance. Ever. I have noticed: warping, rust in the holes, brake dust building up and blocking the holes, warping, cracking, warping, and excessive pad wear. Did I mention warping? And like a dummy, I kept trying fancy rotor combinations. I've only seen disappointment. Even more disappointment when you consider the premium price for the various rotors I've tried. I've found that you can't go wrong with quality, plain rotors and a high-quality pad. Save money on the rotors and spend it on the pads.

I know there are many people who are happy with your Stillen/DBA combo, and I have no doubt they are the highest quality available.

Lestatsghost - I have driven I70 in Colorado, as well as SR82/Independence Pass and Pikes Peak, all in the WJ. Even with OEM pads and glazed rotors, I had no issue. Then again, I know how to drive. When I pulled up to the brake check station on PP, my brakes measured in at 116°F on the infrared pyrometer. The Camry in front of me was over 500 though, the guys made them pull over and stop to let them cool down. I suppose I did speak in error; people are dumb enough to break anything. Although I will have to ask you just how many Corvette ZR1s you've seen smoke the brakes on I70.

[paulMiller]

**Added note: after long trip this past week I've determined our mileage after this brake swap is much better. I mean quarter tank better on the same run.

1999 Grand Cherokee Limited V8, got it used many years ago and had brake pulse and shaking on brake application. In early 2000s, had the brakes done by a shop but the problems came back over the years (we don't drive a lot of miles on it). At that time I did not know about the Teves problems.

Over the last few years the pulsing got worse (Teves again) and after driving a while the front end wobbles badly upon brake application, sometimes shaking the whole car to the point that I have to ease off the brakes. Hitting potholes or bumps would make the steering wheel shake in a rotational way.

Finally, I spent a lot of time here looking at the solution and went into the local parts store and got Akebono calipers, pads, new rotors and brake fluid. I found that the mating surface between the hub and rotor was really rusty and probably uneven so I spent a lot of time cleaning with rotary wire wheel and powered scotchbrite pads and that seems to have made a difference.

The old Teves came off and the sliders were really stiff and they went back to the store as cores. I installed the new pads into the Akebonos, put on the new rotors after cleaning the mating surface really well and then pushed through an entire can of brake fluid until all the front lines were clean and fresh again.

So, the wobble is gone. The Jeep actually rolls a lot better and accelerates down the same hills a lot faster. The wheel shake on bumps is almost all gone and there is no more pulsing or front end shake (after two weeks).

I did buy a new stabilizer but have not yet installed it, but I will. I have 135,000 km on this vehicle. Many thanks for the help here and if anyone has similar issues, the swap is actually easy but I did take a lot of cleaning time so it took more than a day for me. The fix has basically made this a good vehicle again. I did a quick check of ball joints and other obvious areas that I thought would be worn but all seems tight so I did not replace any other original steering or suspension parts on this Jeep. So far, so good.

Paul
Calgary

I just replaced the original Steering Stabilizer with a moog product. I had wheel shake prior to the change but the wobble had disappeared after Akebonos calipers (above) were installed. Once I replaced the SS, the wobble in the steering from hitting bumps and grooves disappeared. I found the bolt to hold the original SS was either worn or undersized and the end of the SS was quite loose on the worn bolt shaft. Easy fix. The original SS was actually (100,000 miles) fairly stiff so perhaps the bolt fix alone would have been sufficient. Check the bolt if you wobble on bumps. Easy fix. Note, it come out from the top (bolt) and the nut is integral to the suspension so don't try to remove the nut like I did LOL. I trashed the nut so had to drill out the threads and install a bolt and nut arrangement.

[ExpeditionXJ]

Search works... good thread here.

My wife came in the other day and mentioned a front end shake when applying the brakes in her 99, now i see the Teves are the issue. I want to order the Akebono conversion but i'm still confused on one aspect. Some have mentioned their kit arrived with all hardware needed, others did not. If i find myself missing hardware will the Teves hardware work or will i need to run to the dealer?

I'll PM Kolak, but i assume his kits utilize new calipers and not a rebuilt unit?

[leadsled jeep]

Kolak kits come with everything and all new parts.