Brembo Brakes Feel Rough

[Steve O]

Hi All. I notice a roughness in the brakes when I apply them. Not a shimmy like warped rotors. Not a grind like damaged pads. But not smooth. I'm used to brakes feeling as smooth as glass. These brakes feel as smooth as saw cut lumber. Any others having this experience?

 

[phildeez]

Very similar to this https://www.kiastinger.org/forum/threads/1334-Stinger-GT-braking-vibration

 

[PAULSTINGERGT]

yes I have and I took my Gt2 in last week they did no trouble shooting they just ordered new rotors without new pads. The parts are coming next week. I will keep you posted. I think it is problem from what I am investigating but many people do not recognize it because of lack of knowledge.

 

[PAULSTINGERGT]

I had the new front rotors put on today and asked that they not drive the car. I wanted to bed my used (2000mi) pads with the new rotors the way you are supposed to. I have great article I found in trying to figure out how in the world my new Brembo rotors could be pulsating knowing with there is no way they could be warped. In all the videos I watched with people test driving the hell out of the car with no complaints it was bugging me why did this happen to my car. However, I found some other people kind of describing what I was experiencing. If you google Stop Tech Warped Rotors you will find an informative article that basically states there are very few if any rotors that are actually warped! I won't go into too much detail but basically I probably did something wrong when I got the car. I probably was trying to break in the engine and brakes but couldn't control myself and got the brakes pretty hot and didn't properly bed the brakes. Yes, one can get a 4000 lb cars 14" brakes very hot on the street with not so prudent driving. Then after some very spirited driving I plain probably stopped at a light for a minute or two with my brakes full on not realizing what I was doing. The bothersome part of this is I have had several great cars that I have driven aggressively on the street and stopped at a light or two with no problems. In my research as to why my superior Brembo brakes had this shudder/pulsation I found some other people with similar complaints. Also a lot of dissatisfaction with Brembo pads. For example I love how my $21k civic sport had initial bite (finally good brakes on a Honda) and my 2018 BMW X3 M40i will throw you into the windshield especially after driving the Stinger because you have to press so relatively hard in the KIA. I know this is all very subjective and one person might not like heavy initial bite but I would have to assume most people driving a sporty car want the brakes to bite hard and then let you modulate them. Anyway I digress. So when Kia said they will replace the rotors but not the pads I was upset and going to escalate it because it goes against 35 years of car experience. But I went home and read the article again and it clearly stated you can bed used pads to new rotors especially because the pads where fairly new. I waited for the rotors to come in and they did rather quickly. I went back and forth on replacing the pads and tried searching for something aftermarket that I had experience with. In the end I decided to let it be because this is basically Kia's recommendation and if I have the same problem I obviously don't want aftermarket parts. So my hope is the used pads have all the coating worn off and I will bed the used pads to the new rotors the way it states in the article which is a pretty common process. I didn't have time or the road to do it yet which I told myself I was going to do right away but I was kind of afraid. Afraid of what? Afraid to duplicate the problem again on my $50000 stinger with Brembo brakes that I was beginning to hate to drive because of the brakes. So to sum up the article and I haven't read it for a few days but I believe I had pad transfer which basically happens when you do not properly and uniformly transfer the pad material over/into the brake rotor (bedding the brakes). Then you if you get the brakes hot and step on them for an extended period like waiting at a long light the spot where the pad was will actually transfer over enough onto the rotor. All it takes is .0004 and .0001 is real annoying especially to someone who is in tune with their vehicle. The article states that the rotors are cast iron and the molecules when heated with the heated pads are clamped together this can easily happen. If this is hard to understand imagine when you drove a car that was sitting for a really long time. So long that the rotors had a lot of rust but no rust right where the pad was because it shielded it from the elements. When you drove and pressed the brakes there was a roughness and shudder and pulsation depending on the speed and your brake pressure. Eventually if the rust was not too bad you would wear it off and the problems might even go away. You can see videos on you tube that show cleaning up the rotors with an abrasive disk. The author of the article said that if the pad transfer was not too severe you could try something similar with Garnet paper. Not sand paper but actual Garnet paper and taking it to the rotors to aggressively try to remove the material which sometimes you can actually see the outline of the pad. I know this is a lot and probably boring to some but I had a problem and it's great I got new rotors but I don't want it to happen again and I don't want it to happen to anyone else. I will try to bed the pads tomorrow and not clamp my pads anytime after they are very hot and keep you posted if I have the same issue or not.

 

[mldavis2]

Good post, [MENTION=751]PAULSTINGERGT[/MENTION]. I have posted similar information somewhere either here or on another forum. I do take exception with one thing you said from other information.

You can indeed warp a rotor. Putting one on a lathe and turning it will show that very clearly. My experience does not include ceramic pads, but I know with the older asbestos pads and rotors you want to avoid long stops with pad pressure. The problem there is that cooling is uneven. If the pad contacts, say 20% of the rotor surface, that contact area cools at a very different rate that the other 80% of the rotor that is exposed to the air (and sometimes water in the rain which is worse.) When you come to a long, hard stop such as a downhill off-ramp from the interstate, stop a little short of your normal stopping distance from the intersection or car ahead of you and let the car creep slowly forward every few seconds. That allows the rotor to turn and cool more evenly and avoids warping. My wife doesn't do that and she warps rotors on my G8 all the time. I've never had warped rotors on my GTO which she never drives. Unfortunately my Stinger is "her" DD so I must "up" my game on brake instruction. Right now my Brembos are smooth as silk.

 

[Steve O]

Fantastic info guys. My rotors are probably not going to settle in as they seem to be less pulsing or grinding than they were a week ago. But the explanations are very insightful and I buy them as a technical gay. That's mechanically technical as opposed to a tech guy as in software... Anyway, neither my 1970 Monte Carlo, nor my 1985 Jetta Carat had brake problems. My 1986 Merkur XR4ti (aka Xerati) had nothng but rotor problems. My 1989 SHO too. Then my 1992 Alfa Romeo 164S was bulletproof in all manner of performance and reliability. All my Saabs, an 02, 05 and 09... NO PROBLEM. Conclusion. They don't make brakes like they used to. But Ford does. LOL.

 

[mldavis2]

My '75 Saab EMS had good brakes but I must have replaced the pads with every other oil change. Super soft. Never a rotor warp problem, however.

 

[Steve O]

The dealer installed new rotors. Problem solved so far. I haven't tested them yet but that will happen and if they are a problem again I'll advise.

 

[PAULSTINGERGT]

That is great. I have mixed feelings. The Stinger brakes can be annoying. My 2018 BMW X3 M40I has the same size BMW M brakes and they are amazing. Bite so hard, no fade, so smooth, and quite. The Brembos on the other hand are very loud you can hear them, sometimes they still pulsate other times they are acceptable. I never keep my pads clamped down on the rotors especially when I have been driving hard and come to a complete stop. That is what I feel I did the first set if you remember. I have 4000 miles and finally the factory grind swirl lines are gone and all you can see is the normal lines like a record. I have posted about the Race Chip install and my problems I have just experienced like many with sputtering and a check engine light. Also like you Steve I feel the suspension is way to soft. I will do the springs also having the adjustable settings means we can not do coil overs. I think the exhaust needs to be more adjustable like the B58 on my BMW it is so nice but I do not like loud exhausts and it is growing on me after 4000 miles. Like you I just want my car Zen.

 

[Volvowith18psi]

Remember, Most if not all new pads and/or rotors need to be properly bed in by following the manufactures guideline. This usually consists of 8+ 50mph->10mph and repeat in rapid succession to heat cycle everything then a 2-3 mile drive to cool them down.

If done properly, you will smell the brakes.