I share your feelings about the mess that some pads leave....my MINI factory pads were horrible, you couldn't drive around the block without them turning black!
But when I switched to some fairly high end ceramic pads, within 5K miles I had brake pulsation in front. Never had it with the factory pads.....
Good semi-metalic pad material has run into the CARB. See what is available in Australia or NZ and import them.
In reply to TurnerX19 :
This is a point that I had never thought of. Makes a lot of sense.
Thinking about it, if everything is going to leave deposits when it gets overheated, there may be a reason to do that National Mod after all. Bigger rotors and more caliper pistons will, in theory, make it easier for the car to stop with less effort. And I'm definitely getting deposits and overheating/glazing (see previous posts in this thread). Bigger brakes that work with less effort might negate the whole pad material conversation a bit.
I ran Z23s on the fronts '17 Elantra Sport after I cooked the stock brakes at Road America. I had the on the car when I traded it in--felt like they were decent for the money...certainly braked as well as stock. I don't think that they were overly dusty either.
If I need brakes on the GT, based on what I'm seeing, they would be my go to.
I decided to actually LOOK at the rotors yesterday to see if I could see any weirdness. And yeah...
Running a finger over the surface, and it feels a little lumpy on all of them. The top two shots are the fronts, and you can see the spots on them clearly. They look overheated in person, too. When I swap the wheels, I will either get these cut or just flap disc the deposits off and see if it helps. I may still do the big brake mod, but if I could hold off on that, it would be preferable.
The dumb thing is, this car has pretty large front rotors at 12+". It only weighs 2900lbs. When it was new, I was actually impressed by how well they worked, but it hasn't felt the same in years.
Now, riddle me this: My Power Wagon weighs almost 5000lbs and stops fine with rear drums and 10" front discs. My old Mazda3 had 11" front brakes and stopped fine as well. I was running el cheapo Max Brakes drilled/slotted rotors and carbon ceramic pads on that most of its life. It's braking system is VERY similar to the Kia but with smaller rotors.
I don't understand why the Kia can't just work. On paper, it should be great! Why the pads keep leaving enough deposits to throw things out of balance is an annoying mystery.
Would adding cooling help this issue? I'm guessing it's not an over heating issue but if cooling would help I would slap some Boxster air deflectors on the control arms and see what happens.
I put Bosch blue ceramics on the back of my Subaru and have been really impressed. Just another budget option.
In reply to spandak :
Maybe, but I'm not sure. It might just be a "brake pads just suck now" issue. My wife's CX-50 has a slight pulsation coming down from highway speed too, although it's not as pronounced or consistent as my car. I used Dynamic Friction pads and rotors on that one too. And yup... deposits all over the rotors.
I know it sounds dumb, but I never had deposit issues with the Max Brakes slotted and drilled rotors I used on my Mazda3 for years. I only used those on the car because they were dirt cheap at the time, but they ended up being really decent brakes. They never had the cheap slotted/drilled cracking issues that you always read about. Maybe the slots helped keep the pads from leaving deposits? They don't have a set that fits my car, but Power Stop does make one, and I'd be willing to bet they are the same thing.
I have a 65k service (aka an oil change and look at fluids) to do in the next couple weeks. I'm planning on making the summer wheels switch at that time and taking a look at the brakes, my favorite activity! I plan on at least hitting all the rotors with a flap disc or similar and seeing if that helps the vibration/chatter issue since the rotors are pocked with deposits.
That said, I am 99% sure that I've made up my mind about doing the National Brake upgrade. I asked in a FB group if anyone else did it, and aside from the usual responses telling me to dump $600+ on EBC pads and multi-piece slotted rotors, a few people chimed in and said that they had the same exact issues I was having and doing the mod solved them. I priced it out, and I can get new Mando (aka factory OEM) calipers, decent blank rotors, and SEMI-METALLIC pads for around $250. That sounds like a bargain to me. The fact that they make a semi-metallic pad in that size is also appealing, and those pads are dirt cheap to boot compared to what's available for the stock brakes.
One guy sent me these pics to show just how much larger they are than the stockers:
That's quite the difference! The thing I don't get is why they didn't just do this to begin with. These cars have larger brakes than the regular Forte already. They spent time developing all sorts of GT-specific parts, like the stainless exhaust, multi-link rear suspension in place of the beam axle, and more. Why didn't they just bolt these on if they were going to go larger anyway? I don't get it at all.
Yesterday, I did my 65k service, which meant I did an oil change and looked at things under the hood; all good there. Engine is doing great, and not burning oil, leaking things, etc.
I also changed out the winter wheels for my "3 season" wheels. While I was there, I decided to take a look at the brakes again, because the shaking under braking has become unbearable. Were the rear calipers frozen again?
YOU BET!!!
I'm not sure how many times this has happened now, but one of the rear calipers had the slides freeze up. This time, the grease didn't solidify, thanks to my use of synthetic slide grease last time I had everything apart. So, what happened now?
This is the passenger side rear caliper bracket and its pins. Two things happened:
-One of the pin boots swelled up to the point where it was letting air in and "air locking" the pin from movement
-The pin on the left with the rubber grommet on the pin had the rubber swell up and lock the pin in place
Very strange.
In all my years, I haven't had a pin boot swell up before. I talked to my mechanic nephew about it, and he said he's seen this a lot lately, and he thinks it's due to the slide grease. The newer formulations of this stuff don't like rubber apparently, and they make it soften and swell after a while. His dealer uses a special product that is more of a mineral lube than a grease and not the same as the parts store stuff. They haven't seen any issues since they switched over.
The strange thing is, the other side is fine, as are the fronts. It's just this one was the lucky winner. At least this time, it froze up open. Some new boots and one new pin (the one with the rubber) and things were moving freely again.
But because it froze again, it glazed and overheated the front rotors even worse than they already were. These were pretty bad:
These rotors have about 5k miles on them. Plenty of thickness left, but tons of deposits and hot spots. They don't feel warped by the touch, but they were cooked. I figured I could just get them cut at the local O'Reilly and call them good, just to get a fresh surface on them.
WRONG AGAIN!
Despite every store having one, none of the O'Reilly stores in my area know how to use the rotor lathe. "Just buy new rotors" was the answer I got. Yeah, thanks, Captain Obvious. No other shops/stores in the area bother with those either, so I decided on hitting them with my Death Wheel Brush Thingy and tossing them on. That at least knocked the deposits off, and seemed to make things at least a little better.
Braking is improved, and all of the calipers are working now, but it is still not great. They still shake a bit stopping from higher speeds, and generally feel terrible. I am hoping it self-corrects, but I don't have my hopes up.
At this point, I think I'll get the "National" brake mod bits, all new boots and pins for the rears, and that fancy slide lube and hope that the 6th time is the charm.
After doing some research, I feel like a big dummy.
Yup, that brake grease I used 100% swells up seals. Specifically, I used this:
This is EXACTLY what's going on and likely causing all my current problems. At first, it was catalyzed, hardened grease in the slides from the factory, but now I've compounded the issue with a new problem. So yeah, despite what the bottle says, DO NOT use this on the caliper pins. It is, however, good for the pad ears, and I'll continue to use it for that.
I ordered up all new seals for the calipers front and rear, and a bottle of this stuff:
This is a silicone-based lubricant, and it doesn't hurt rubber. Lesson learned.
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