Front/Rear brake balance

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My 2017 Acura TLX seems to have brake balance very heavily biased to the front. While some of this is normal in fwd vehicle in my case it seems extreme: rust on rear rotors from rain can persist for weeks even with regular brake use.

I'll take it in to the dealer but expect the usual "it's normal, please leave" routine. Is there a way a dealer can dial in more rear brake bias? Is there a way brake balance can be tested? I'd like to see the dealer with some level of knowledge and appreciate any help offered. Thanks.
 
Rust on the pad contact surface? I'd jack up the rear wheels, spin them and have somebody hit the brake to see if they are working.
 
Welcome to the club!!!, I have /kind of had -the same problem on my 2018 AWD Kona 1.6T. I worked with my dealer day time service manager ( he knew me from my 14,000 mile Hyundai Elantra semi common bearing/piston issue warranty rebuild) so he worked with me more freely. We went for braking run in mine and then new Kona's and took laser rear disk temps. Mine was about 100 deg less but mine were more broken in so less heat. My comment was I can't get my rear brakes "blued" color or bedded properly because I have such bad rear brake bias. That's how I myself was attacking it, more in the sport driving way. He said call Hyundai if you want to take it further. So I did and you have to use the key words to get it elevated " I don't feel safe in my car, I fear for my safety" and like a light switch they started a file on my car to be elevated and I got NO WHERE. An asian lady could of cared less after 10 minutes of selling my problem. They looked at it as long as slow grandma and grandpa can stop , we don't care about you.

My sub compact SUV/crossover handles good for the average person but I raced cars when younger so I expect more. The Kona would nose dive and the rear would lift in panic braking and sport braking so it would not have enough weight in the rear to use the rear for braking. The Kona AWD has big swaybars but a kinda soft spring rate for a nice ride. Your TLX should be way stiffer. My simpleton Elantra GT was a semi soft sprung car but would not dive or lift in the rear and had GREAT rear brake bias. You would feel the rear braking all the time and it stopped on a dime for a simpleton with a 1.8 liter non turbo car.

I have to assume your car is stiffly sprung like my Honda Fit was. I was going to buy Eibach lowering springs anyway so I ordered them right away and that stopped my front dive and rear lift issue. It seems the Kona had very stiff shock valving with softer springs which make it handle OK but when pushed it dives and lifts. Adding the Eibach lowering spring gave me the increased spring rate, and no need for Koni's or Bilstein's since the stock struts are way stiff and a perfect match for the new springs. It still is not the correct rear brake bias but it is 60% better and livable now. My old tricked out Audi's and VWs you could adjust the rear bias since they were before ABS. I owned a hobby Audi repair shop out of my large when I was younger, so I know cars.

The dealer you went to, you might as well forget them, next you need to call Acura and use those famous words above and get it elevated at the next closest dealer. Have they even bleed the brakes yet??? If you come up short with Acura after being a throne in their side (keep whining nicely) You can always try getting new "slotted" rear brake rotors. NOT drilled. Drilled can crack too easy. I am doing this with my Kona once more after market brake companies come up with them since the rears on mine have never been used before on any car since it is a new platform design. The fronts are Hyundai Veloseter Turbo brakes so those have been around for a while and available. I am partial to EBC with their nice rotor coating.


Here you go for your car. call EBC tech line and get an opinion on what color pad to use for your situation. You should use their pad on their rotors because they have a hard coating and they have special abrasives on the pad to clear it off. And be HARD on your brakes because rear brake take some hour time to break in, way more then the front.

https://www.autoanything.com/brakes/ebc-ultimax-rotors



.
 
a TLX is plenty stiffly sprung and valved. He won't have the problem I had. I would elevate it with Acura corporate and go to a different dealer and do what you have to if they keep denying the issue like mine. There is something more wrong with his since it is Acura's cheap (ha ha) high performance sedan and it is classified as a performance car.
 
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In physics, the majority of stopping power is in the front versus the rear. About 80-90% of braking/stopping a rear OR front wheel drive vehicle is at the front brakes. That's why some cars/trucks you have disc brakes in the front and cheaper drum brakes in the rear.
 
Originally Posted by Mainia
My comment was I can't get my rear brakes "blued" color or bedded properly because I have such bad rear brake bias...
... That's how I myself was attacking it, more in the sport driving way.


No, that is a sign you're overheating your brakes. Nobody needs to try to turn their vehicle into a pretend-race-car to have it work as engineers intended. Recognize public roads are not a race track and drive responsibly. Pick a different vehicle if you cannot drive the same things everyone else does. Good driving, opposed to trying to take a corner as fast as possible to win a race, does not require stopping fast enough that the front of a softly sprung vehicle transferring weight will matter much. It is considered in the design.

The correct approach to this is to have a technician familiar with the braking system (or enough life experience to know what s/he is looking at), test drive, pull the wheel, inspect lines and hoses, check rotor and pad wear and overall condition, check slider rails, check slider pins... see if anything is really wrong or if there is just an expectation that rust should be removed faster than it is.

Remember, so far that is all we know, nothing was mentioned about "it won't stop". Ultimately for us to give any sound advice over the internet we'd need a lot more information after someone has inspected the braking system, including just how much rust there was, how much remains after a reasonable length drive, including good pictures with the wheel off before and after the initial rust observation from sitting and the drive.
 
Just curious. When was the last time the rear brakes were serviced? VERY important to do them at least once a year. The rear rotors are showing corrosion because the pads are probably seized in the caliper brackets.

FYI, I was an Acura dealer tech for 13 years.
 
Originally Posted by mightymousetech
Just curious. When was the last time the rear brakes were serviced? VERY important to do them at least once a year. The rear rotors are showing corrosion because the pads are probably seized in the caliper brackets.

FYI, I was an Acura dealer tech for 13 years.


You could be right, but the car is less than 2 years old and hasn't been subjected to much salt. Seems early for that kind of issue. After owning 20+ cars this would be a first for this stage of ownership.

The car does stop, but since new instead of the pedal being high and hard it's been a little low and soft. Maybe the issues are related?
 
I
Originally Posted by Danh
Originally Posted by mightymousetech
Just curious. When was the last time the rear brakes were serviced? VERY important to do them at least once a year. The rear rotors are showing corrosion because the pads are probably seized in the caliper brackets.

FYI, I was an Acura dealer tech for 13 years.


You could be right, but the car is less than 2 years old and hasn't been subjected to much salt. Seems early for that kind of issue. After owning 20+ cars this would be a first for this stage of ownership.

The car does stop, but since new instead of the pedal being high and hard it's been a little low and soft. Maybe the issues are related?


Two years old and the brakes have not been serviced? Eek! You are lucky the pads are not metal on metal by now. The first brake service is the most important as the brakes are too tight and not enough lube from the factory. Pretty common to see the pads half worn by the time the first B service is due.

Just FYI, I service my own brakes every oil change, which I do every 5000 km. The rear brakes on Honda/Acura seize very quickly.

And yes, I would say it is related. Pads probably have tapered wear. Has the vehicle shown due for a type B service yet?
 
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One thing I think people often overlook when they try to "fix" their brakes or try to make them better is they will put a higher friction coefficient pad on the front of their vehicle without matching it on the rear. What do you think happens when a car was designed for FF pads front and rear and someone decides to put GG pads on the front without also putting GG pads on the rear? Bias would certainly shift forward in that case. If you want to shift bias sightly to the rear putt FF's in the front and GG's in the rear.

But I would guess that 99% of vehicles should be balanced appropriately by matching brake pad coefficients front and rear.

I just dealt with that on my daily driver Civic, the clown previous owner putt GG pads on the front and those were quick to overheat with very little heat in the drums. I put FF pads in the front like was intended and now my brakes are far more balanced.
 
Iì
Originally Posted by mightymousetech
I
Originally Posted by Danh
Originally Posted by mightymousetech
Just curious. When was the last time the rear brakes were serviced? VERY important to do them at least once a year. The rear rotors are showing corrosion because the pads are probably seized in the caliper brackets.

FYI, I was an Acura dealer tech for 13 years.


You could be right, but the car is less than 2 years old and hasn't been subjected to much salt. Seems early for that kind of issue. After owning 20+ cars this would be a first for this stage of ownership.

The car does stop, but since new instead of the pedal being high and hard it's been a little low and soft. Maybe the issues are related?


Two years old and the brakes have not been serviced? Eek! You are lucky the pads are not metal on metal by now. The first brake service is the most important as the brakes are too tight and not enough lube from the factory. Pretty common to see the pads half worn by the time the first B service is due.

Just FYI, I service my own brakes every oil change, which I do every 5000 km. The rear brakes on Honda/Acura seize very quickly.

And yes, I would say it is related. Pads probably have tapered wear. Has the vehicle shown due for a type B service yet?


Visually, there's tons of pad life left as it should be with about 13,000 miles. And given the brake feel has been this way since new I doubt pad wear is the culprit. But I'm suitably chastised and will see my (largely incompetent) dealer for the likely shoulder shrug. Thanks for the input.
 
Originally Posted by mightymousetech
Two years old and the brakes have not been serviced? Eek! You are lucky the pads are not metal on metal by now. The first brake service is the most important as the brakes are too tight and not enough lube from the factory. Pretty common to see the pads half worn by the time the first B service is due.

Just FYI, I service my own brakes every oil change, which I do every 5000 km. The rear brakes on Honda/Acura seize very quickly.

And yes, I would say it is related. Pads probably have tapered wear. Has the vehicle shown due for a type B service yet?


I don't know about "metal on metal" as my Honda Pilot's rear brake pads have lasted 97K, 66K and 52K, but I can attest to the fact that the rears can seize quickly. I've been advocating annual brake checks and lubes due to harsh de-icing chemicals used in the Rust Belt, but I let mine go 2 years 10 months and found the pins stuck and the pads wearing unevenly.
 
Originally Posted by Dave1027
Rust on the pad contact surface? I'd jack up the rear wheels, spin them and have somebody hit the brake to see if they are working.

Yeah that's not right. If the pistons are functioning at all, even 90%10% split, they should at least clear the rust. I think they're locked up. They may be locked up on one side, that is, piston/inside side pad doing all the braking and the outer pad just sitting there.
 
Originally Posted by Dave9
Originally Posted by Mainia
My comment was I can't get my rear brakes "blued" color or bedded properly because I have such bad rear brake bias...
... That's how I myself was attacking it, more in the sport driving way.


No, that is a sign you're overheating your brakes. Nobody needs to try to turn their vehicle into a pretend-race-car to have it work as engineers intended. Recognize public roads are not a race track and drive responsibly. Pick a different vehicle if you cannot drive the same things everyone else does. Good driving, opposed to trying to take a corner as fast as possible to win a race, does not require stopping fast enough that the front of a softly sprung vehicle transferring weight will matter much. It is considered in the design.

The correct approach to this is to have a technician familiar with the braking system (or enough life experience to know what s/he is looking at), test drive, pull the wheel, inspect lines and hoses, check rotor and pad wear and overall condition, check slider rails, check slider pins... see if anything is really wrong or if there is just an expectation that rust should be removed faster than it is.

Remember, so far that is all we know, nothing was mentioned about "it won't stop". Ultimately for us to give any sound advice over the internet we'd need a lot more information after someone has inspected the braking system, including just how much rust there was, how much remains after a reasonable length drive, including good pictures with the wheel off before and after the initial rust observation from sitting and the drive.


Dave9, blue brakes don't necessarily mean they are overheated. I work with a guy that has a ZL1 Camaro with silver non blued rotors. Every other Camaro I have seen has blue rotors, I might add. He drives like you Dave, I said use that car, why even own it if you drive it like Dave. I looked at every car in my place of works parking lot, 40 cars. All makes from junk to a Mercedes. 90% of them had blued rotors. 50% as blued as mine are. How can 90% of the cars be overheating their rotors? I would of thought the engineers have taken in account the vehicle use, weight, and disc size, and pad material choice as you seemed to of stated. I do have time with car since I owned a hobby Audi repair shop with 60 customers years ago, and now am the maintenance guy at a mid sized printer with 3 buildings. I do have "some idea" how stuff works.


Dave9, your "Mr Rogers" way at looking at the automobile industry and car design are just that, from the eyes of Mr Rogers. Maybe you should take a trip to the SEMA show to learn your comment is moot about "how the engineers intended". Changing a family "wallow bucket" car that Mr Rogers finds "calming to drive" can be changed over and made into a well engineered/advanced sport street car, to autocross car, to a full blown race car with ease. It is done daily by millions of people all over the world. Your wish on perfect slow driving everywhere will never happen. We see this "sport" performance driving in automobile advertisements 35%+ of the time. It's part of our culture, gone are the early 80's of 150 hp 301 V8 Pontiac Trans Am's, and Chevy Chevette's can't shift into 4th gear if the tire pressure is too low.

I choose very carefully where I sport drive, NEVER in residential streets, mostly hwy exit ramps, industrial parks on weekends/nights, and I never go over what I and the car can do though 57 years of sport driving. Do I brake hard, in a very aggressive/race style way, yep, that's how you brake in sport driving. I have my car dialed in with added anti-dive geometry and have balanced out my rear bias just from the lack of reducing weight transfer. I now have blued rear rotors A stock Hyundai Kona has HORRIBLE brake bias in an emergency stop, especially for the average driver. Very dangerous in my opinion. Hyundai chose to have a softly sprung, higher dampened car with large swaybars. That style car design is very highly conducive to nose dive and rear lift with almost no rear brake to road engagement as the ABS will cycle the rear bakes to almost 98% non use. I know, I tested 5 different Kona's at the dealer with the service manger. yet my 2013 Hyundai GT (slow nothing special) had superb rear brake bias.

Why did I chose the Hyundai Kona AWD 1.6T, and lowered it 2 inches and not a Corvette or Audi S3 Sport? I like oddball quirky AWD cars and like to build them to my liking. It does 0-60 in 6.6 seconds stock, but mine is a hair quicker. AWD drive is great in the corners, as we can see here. A game changer. I will start it mid video and watch for 5 minutes.

https://youtu.be/p10m0Jdk8tc?t=445

https://www.hyundaikonaforum.com/showcase/2018-kona-awd-1-6t-lowered.1162/

.
 
Originally Posted by Danh
My 2017 Acura TLX seems to have brake balance very heavily biased to the front. While some of this is normal in fwd vehicle in my case it seems extreme: rust on rear rotors from rain can persist for weeks even with regular brake use.

I'll take it in to the dealer but expect the usual "it's normal, please leave" routine. Is there a way a dealer can dial in more rear brake bias? Is there a way brake balance can be tested? I'd like to see the dealer with some level of knowledge and appreciate any help offered. Thanks.


Get the rerar brakes checked or do it yourself. The pads, sliders AND piston must be checked. All must be free and easy to move. This has become such a common issue the last decade it is an outrage. I spent the nineties and nillies fixing cars and maybe had to fix 2 calipers. These days I do several cars a day, 5 days a week. If they are properly assembled and greased it's however a one time deal, I treat most cars during the first service if the owner hasn't had complaints before then. I might not need any spare parts at that time.

Brake balance cant be changed hydraulically by the dealer, but if you want more rear brake effort you can put pads with a higher coefficient of friction. With EBD and ABS there really is no excuse for abysmal rear brake performance, theres a lot of stopping distance left on the table if the rears don't even do half of what they could mand should, and the fronts get an easier life to boot.
 
Originally Posted by Mainia
Welcome to the club!!!, I have /kind of had -the same problem on my 2018 AWD Kona 1.6T. I worked with my dealer day time service manager ( he knew me from my 14,000 mile Hyundai Elantra semi common bearing/piston issue warranty rebuild) so he worked with me more freely. We went for braking run in mine and then new Kona's and took laser rear disk temps. Mine was about 100 deg less but mine were more broken in so less heat. My comment was I can't get my rear brakes "blued" color or bedded properly because I have such bad rear brake bias. That's how I myself was attacking it, more in the sport driving way. He said call Hyundai if you want to take it further. So I did and you have to use the key words to get it elevated " I don't feel safe in my car, I fear for my safety" and like a light switch they started a file on my car to be elevated and I got NO WHERE. An asian lady could of cared less after 10 minutes of selling my problem. They looked at it as long as slow grandma and grandpa can stop , we don't care about you.

My sub compact SUV/crossover handles good for the average person but I raced cars when younger so I expect more. The Kona would nose dive and the rear would lift in panic braking and sport braking so it would not have enough weight in the rear to use the rear for braking. The Kona AWD has big swaybars but a kinda soft spring rate for a nice ride. Your TLX should be way stiffer. My simpleton Elantra GT was a semi soft sprung car but would not dive or lift in the rear and had GREAT rear brake bias. You would feel the rear braking all the time and it stopped on a dime for a simpleton with a 1.8 liter non turbo car.

I have to assume your car is stiffly sprung like my Honda Fit was. I was going to buy Eibach lowering springs anyway so I ordered them right away and that stopped my front dive and rear lift issue. It seems the Kona had very stiff shock valving with softer springs which make it handle OK but when pushed it dives and lifts. Adding the Eibach lowering spring gave me the increased spring rate, and no need for Koni's or Bilstein's since the stock struts are way stiff and a perfect match for the new springs. It still is not the correct rear brake bias but it is 60% better and livable now. My old tricked out Audi's and VWs you could adjust the rear bias since they were before ABS. I owned a hobby Audi repair shop out of my large when I was younger, so I know cars.

The dealer you went to, you might as well forget them, next you need to call Acura and use those famous words above and get it elevated at the next closest dealer. Have they even bleed the brakes yet??? If you come up short with Acura after being a throne in their side (keep whining nicely) You can always try getting new "slotted" rear brake rotors. NOT drilled. Drilled can crack too easy. I am doing this with my Kona once more after market brake companies come up with them since the rears on mine have never been used before on any car since it is a new platform design. The fronts are Hyundai Veloseter Turbo brakes so those have been around for a while and available. I am partial to EBC with their nice rotor coating.


Here you go for your car. call EBC tech line and get an opinion on what color pad to use for your situation. You should use their pad on their rotors because they have a hard coating and they have special abrasives on the pad to clear it off. And be HARD on your brakes because rear brake take some hour time to break in, way more then the front.

https://www.autoanything.com/brakes/ebc-ultimax-rotors



.


You're not alone in this. See my previous post. I'm a Hyundai master tech and deal with this daily. Most people aren't aware their brakes aren't working optimal but once you get them serviced correctly (fronts aswell) you will find you can dose the brakes much better, it's less of an on/off switch. But even then, Most hyundai brake calipers are undersized at the rear, and there's no changing the brake bias hydraulically unless you find some beefier parts from another car that fit. But first get the brakes you got to work properly. All parts are sticking but on kona especially it's often the pistons in the boots. From new!
 
Originally Posted by anndel
In physics, the majority of stopping power is in the front versus the rear. About 80-90% of braking/stopping a rear OR front wheel drive vehicle is at the front brakes. That's why some cars/trucks you have disc brakes in the front and cheaper drum brakes in the rear.


About 80% front if you're doing a panic stop at 1G, for a FWD with a typical 60/40 weight distriubtion. Less if it's raining as you won't be stopping at 1G, and nearly 60/40 on snow and ice. for a RWD vehicle the bias shifts about 10% more towards the rear.

Trucks have a high centre of gravity which makes the load transfer more pronounced compared to cars, and when empty they have a lot of weight on the front to start with. So they could possibly see 90%, and a short SUV like a Renegade close to 100%. But when loaded in the back it's a different story...
 
Originally Posted by Tman220
One thing I think people often overlook when they try to "fix" their brakes or try to make them better is they will put a higher friction coefficient pad on the front of their vehicle without matching it on the rear. What do you think happens when a car was designed for FF pads front and rear and someone decides to put GG pads on the front without also putting GG pads on the rear? Bias would certainly shift forward in that case. If you want to shift bias sightly to the rear putt FF's in the front and GG's in the rear.

But I would guess that 99% of vehicles should be balanced appropriately by matching brake pad coefficients front and rear.

I just dealt with that on my daily driver Civic, the clown previous owner putt GG pads on the front and those were quick to overheat with very little heat in the drums. I put FF pads in the front like was intended and now my brakes are far more balanced.


Absolutely, make sure the 4 wheels do their share of the braking to start with. Electronic Brake force Distribution will only reduce brake pressure on the rear brakes if needed, not reduce front brake force or increase rear beyond what your foot is doing. very common mistake to upgrade the pads on the front and make the problem worse. But the car will nose dive more and that gives the impression of more brake effort I suppose.
 
Originally Posted by Danh
My 2017 Acura TLX seems to have brake balance very heavily biased to the front. While some of this is normal in fwd vehicle in my case it seems extreme: rust on rear rotors from rain can persist for weeks even with regular brake use.

I'll take it in to the dealer but expect the usual "it's normal, please leave" routine. Is there a way a dealer can dial in more rear brake bias? Is there a way brake balance can be tested? I'd like to see the dealer with some level of knowledge and appreciate any help offered. Thanks.

The OEM shop manual for your vehicle should state in the brake section what the front/rear brake line pressure is at various brake applications.
 
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