SQ5 Brakes - terrible pedal feel and non-linear stopping
04-29-2015, 06:16 PM
#11
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Well there is no programming in the brakes except for ABS.
It is a purely mechanical system. There is nothing that can be done software wise to fix it.
To me it feels like a booster problem. They tune a lot of brake systems between the booster and master cylinder. I wonder if these parts changed from '14 to '15 or if the complaints are strictly for '15's?
If I don't get resolution from the dealer I'm going to talk to a few old co-workers who design brake systems.
No good brake engineer would drive that car and say its right, especially not for a 65K car.
It is a purely mechanical system. There is nothing that can be done software wise to fix it.
To me it feels like a booster problem. They tune a lot of brake systems between the booster and master cylinder. I wonder if these parts changed from '14 to '15 or if the complaints are strictly for '15's?
If I don't get resolution from the dealer I'm going to talk to a few old co-workers who design brake systems.
No good brake engineer would drive that car and say its right, especially not for a 65K car.
04-29-2015, 08:29 PM
#12
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Completely agree, on '15 sq5 the feel is very "nonlinear", 13 s4 was fine, actually liked it better than bmw (at least 2010 5 series). This just feels wrong. Different amount of pressure under what seem like similar circumstances, hard to predict when it will "catch", engine braking comes in out if the blue (as if the car thinks it knows better) and all of a sudden big increase in perceived braking and nose dive. Have to say that it's the first car I drove in 20 years that is like this. In fact this takes a lot of enjoyment and safety (perception) out of driving.
Dealer says this is normal, q5 loaner felt a lot better (2.0 version almost felt normal, I'd be much happier with this feel), a4 2.0 fwd felt similar but not as bad (perhaps due to weight and ride height).
Would love to see this addressed, shame on Audi for allowing this to continue.
Dealer says this is normal, q5 loaner felt a lot better (2.0 version almost felt normal, I'd be much happier with this feel), a4 2.0 fwd felt similar but not as bad (perhaps due to weight and ride height).
Would love to see this addressed, shame on Audi for allowing this to continue.
04-30-2015, 02:28 AM
#13
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I thought i was only one. same thing here 2015 sq5. 60% of the brake starts at the very bottom then all sudden is the 100% mark very hard to do smooth braking.
not good for winter time.
not good for winter time.
04-30-2015, 03:08 AM
#14
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Well it sounds like they do have a consistent problem.
Does anyone know if the calipers are the same on all the Q's?
I know on my S4 you get a totally different caliper but from what I read they just put a plate over a stock Q5 caliper to make it look like a bigger forged caliper.
If the calipers are the same then I would expect the booster/master cylinder to be identical across the board.
If its a different caliper then I would think there should be a difference.
Were the 14's like this? Anyone have access to a parts list to see if the booster/MC changed from year to year?
Does anyone know if the calipers are the same on all the Q's?
I know on my S4 you get a totally different caliper but from what I read they just put a plate over a stock Q5 caliper to make it look like a bigger forged caliper.
If the calipers are the same then I would expect the booster/master cylinder to be identical across the board.
If its a different caliper then I would think there should be a difference.
Were the 14's like this? Anyone have access to a parts list to see if the booster/MC changed from year to year?
Last edited by Eric_C; 04-30-2015 at 03:11 AM.
04-30-2015, 10:02 AM
#15
AudiWorld Super User
SQ calipers are different but still Audi parts bin...
Calipers are not the same as other Q's, whether pre or post 2013 era caliper changes with the Brembo sourced stuff. Plus of course the front rotor sizing and construction (semi floating) vary.
But wait, rummage around in the parts bin. Look at the current D4 A8 (3.0 type motor) with the baseline brakes. Same semi floating rotor, same caliper, actually a somewhat lighter vehicle than an SQ5 I think. Standard parts bin engineering. It's a weird cross over most don't think of--compared to an S4, S5, A or S6, but that's where it apparently is. As far as programming--really only relevant near limit as ABS or the handling nannies kick in--or more relevant the booster and master cylinder and proportioning and all, no idea what they pulled out of the bins or if they just grafted A8 baseline calipers onto Q5 basic set up. Best check is often a part # comparison, like SQ to Q5 3.0T or maybe stuff like S5 given platform overlaps.
A guess of trying to get a feel you like better is to try other pads, after the usual brake bleeding of course. Given the A8 crossover and that being in Europe yet longer, probably other stuff out there already. When I want (a well designed) stock feel and progressive, I run EBC red. But then pads are a whole "religious" subject unto themselves, as my idea here may trigger. You can go all along the spectrum from street to track if the listings are there, and either semimetallics or ceramics. Your sense of feel reminds me of (bad) ceramics, and car manufacturers including Audi of late seem to drift that way to offset dust complaints. I don't find that with EBC's, but there are some pretty well known ceramics out there thought of as pretty greasy and some call unsafe. Comes up in the Mini S world much more than I ever see in a higher priced Audi board context. That aside, if Audi moved the compound to reduce dust (which often means harder but may also be a color change to mask it), you may be running into a sometimes downside of specifics of compound. They also have to deal with some obscure U.S. (and maybe other country) rules as a manufacturer that regulate emergency stopping pedal pressure. Since the upper limit is basically your proverbial little old lady, they are boxed into a narrower total pressure range. Pads can play in here to this facet too, and was a reason Audi cited in the mid 80's for then more dust as it played with compounds. More toward semimetallic in that era.
But wait, rummage around in the parts bin. Look at the current D4 A8 (3.0 type motor) with the baseline brakes. Same semi floating rotor, same caliper, actually a somewhat lighter vehicle than an SQ5 I think. Standard parts bin engineering. It's a weird cross over most don't think of--compared to an S4, S5, A or S6, but that's where it apparently is. As far as programming--really only relevant near limit as ABS or the handling nannies kick in--or more relevant the booster and master cylinder and proportioning and all, no idea what they pulled out of the bins or if they just grafted A8 baseline calipers onto Q5 basic set up. Best check is often a part # comparison, like SQ to Q5 3.0T or maybe stuff like S5 given platform overlaps.
A guess of trying to get a feel you like better is to try other pads, after the usual brake bleeding of course. Given the A8 crossover and that being in Europe yet longer, probably other stuff out there already. When I want (a well designed) stock feel and progressive, I run EBC red. But then pads are a whole "religious" subject unto themselves, as my idea here may trigger. You can go all along the spectrum from street to track if the listings are there, and either semimetallics or ceramics. Your sense of feel reminds me of (bad) ceramics, and car manufacturers including Audi of late seem to drift that way to offset dust complaints. I don't find that with EBC's, but there are some pretty well known ceramics out there thought of as pretty greasy and some call unsafe. Comes up in the Mini S world much more than I ever see in a higher priced Audi board context. That aside, if Audi moved the compound to reduce dust (which often means harder but may also be a color change to mask it), you may be running into a sometimes downside of specifics of compound. They also have to deal with some obscure U.S. (and maybe other country) rules as a manufacturer that regulate emergency stopping pedal pressure. Since the upper limit is basically your proverbial little old lady, they are boxed into a narrower total pressure range. Pads can play in here to this facet too, and was a reason Audi cited in the mid 80's for then more dust as it played with compounds. More toward semimetallic in that era.
Well it sounds like they do have a consistent problem.
Does anyone know if the calipers are the same on all the Q's?
I know on my S4 you get a totally different caliper but from what I read they just put a plate over a stock Q5 caliper to make it look like a bigger forged caliper.
If the calipers are the same then I would expect the booster/master cylinder to be identical across the board.
If its a different caliper then I would think there should be a difference.
Were the 14's like this? Anyone have access to a parts list to see if the booster/MC changed from year to year?
Does anyone know if the calipers are the same on all the Q's?
I know on my S4 you get a totally different caliper but from what I read they just put a plate over a stock Q5 caliper to make it look like a bigger forged caliper.
If the calipers are the same then I would expect the booster/master cylinder to be identical across the board.
If its a different caliper then I would think there should be a difference.
Were the 14's like this? Anyone have access to a parts list to see if the booster/MC changed from year to year?
Last edited by MP4.2+6.0; 04-30-2015 at 10:57 AM.
04-30-2015, 11:44 AM
#16
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Picked the car up today after the bleed, zero difference.
This is not a pad issue. The pedal will fall on its own with very light pressure. Braking performance at the limit is fine.
I wonder if the ABS system monitors brake system pressure. I suspect you would see a very small increase until you hit the bottom of the pedal.
Audi has their regional rep in next Wednesday. AOA also called me today since I made a complaint about it in the 30 day survey.
Those 30 day surveys are big in the industry and we used to pay very close attention to them when info came in from customers.
This is not a pad issue. The pedal will fall on its own with very light pressure. Braking performance at the limit is fine.
I wonder if the ABS system monitors brake system pressure. I suspect you would see a very small increase until you hit the bottom of the pedal.
Audi has their regional rep in next Wednesday. AOA also called me today since I made a complaint about it in the 30 day survey.
Those 30 day surveys are big in the industry and we used to pay very close attention to them when info came in from customers.
04-30-2015, 12:53 PM
#17
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Think what you want but I don't agree with you
I don't agree with you, but whatever. Seems like I'm the only guy who actually told you what the front caliper system is and where it came from, but you still just dismiss. Fill out surveys galore; won't change much--as a 35 year owner. The follow on service surveys do some, since they take it in the wallet apparently. But one ding and you're probably somewhat a service hot potato after so use the bullet carefully if ongoing relationship matters. One to one phone calls and e mails are typically what it takes--with some diplomacy--to get attention and some progress. Implied survey threat that seemed in there probably isn't the Dale Carnegie school either.
Meanwhile, pads have a whole lot to do with feel throughout the range if you have driven same vehicle over time with a range of pad choices, including sometimes different choices front to rear. Thus you will find descriptions like linear, progressive, grabby, initial bite and several others that try to capture differences in pad feel. Your own choice of title said "non-linear." And if my description about delta's with ceramic and non-ceramic compounds didn't register, we are in different worlds of brake backgrounds.
ABS theory is candidly ridiculous to me; seems like scope lock just being direct. Thus I tried to give you some new thinking and angles and experience, but you just dismiss it. Meanwhile, zero do do with ABS functions until it starts to lock up. Only other element, is yes it is looking at pressures, but especially it is also looking at rate of change of pressures--that is for the crash guard protective systems to cut in forcefully when it sees an initial stab on brakes and then pressure backing off as ABS cycles, when in a crash scenario it should be held. Meanwhile, I would not go with the ABS ideas myself to Audi higher ups if you are trying to show some technical facility with them; they logically won't buy. Meanwhile, if you go with your own description of pedal falling under slight pressure, that is logically more the brake booster set up (assuming pedal doesn't go toward floor per bad master cylinder) if you want to pursue hardware side. Still zero to do with ABS. There are some weird vacuum scenarios too than can affect booster, maybe yet more esoteric with a blown set up. But those are yet more advanced, set up specific and only occasionally covered in Audi technical literature. If immediately preceding throttle seems to have no relationship, unlikely at play.
As a constructive suggestion meantime, you might go out and try to re-bed the pads on there now. If it were mine with this description, I would go do some spirited runs and sequential 60-0 type stops and heat them up a good amount, followed by some gradual cool down for the following 15+ minutes of drive time. May or may not do something, but might affect it if pad surface glazed over some. After that for when ever the next service re-look is, based on what you said/I read and the system in general, I would be more than anything describbing feel to them and getting them on board same recognition. Then maybe softly nudging on brake booster (and any ancillary parts) review and maybe a pad change out on their nickel in case that shows any improvement. Dale Carnegie would be more "have you thought about..."
Meanwhile, pads have a whole lot to do with feel throughout the range if you have driven same vehicle over time with a range of pad choices, including sometimes different choices front to rear. Thus you will find descriptions like linear, progressive, grabby, initial bite and several others that try to capture differences in pad feel. Your own choice of title said "non-linear." And if my description about delta's with ceramic and non-ceramic compounds didn't register, we are in different worlds of brake backgrounds.
ABS theory is candidly ridiculous to me; seems like scope lock just being direct. Thus I tried to give you some new thinking and angles and experience, but you just dismiss it. Meanwhile, zero do do with ABS functions until it starts to lock up. Only other element, is yes it is looking at pressures, but especially it is also looking at rate of change of pressures--that is for the crash guard protective systems to cut in forcefully when it sees an initial stab on brakes and then pressure backing off as ABS cycles, when in a crash scenario it should be held. Meanwhile, I would not go with the ABS ideas myself to Audi higher ups if you are trying to show some technical facility with them; they logically won't buy. Meanwhile, if you go with your own description of pedal falling under slight pressure, that is logically more the brake booster set up (assuming pedal doesn't go toward floor per bad master cylinder) if you want to pursue hardware side. Still zero to do with ABS. There are some weird vacuum scenarios too than can affect booster, maybe yet more esoteric with a blown set up. But those are yet more advanced, set up specific and only occasionally covered in Audi technical literature. If immediately preceding throttle seems to have no relationship, unlikely at play.
As a constructive suggestion meantime, you might go out and try to re-bed the pads on there now. If it were mine with this description, I would go do some spirited runs and sequential 60-0 type stops and heat them up a good amount, followed by some gradual cool down for the following 15+ minutes of drive time. May or may not do something, but might affect it if pad surface glazed over some. After that for when ever the next service re-look is, based on what you said/I read and the system in general, I would be more than anything describbing feel to them and getting them on board same recognition. Then maybe softly nudging on brake booster (and any ancillary parts) review and maybe a pad change out on their nickel in case that shows any improvement. Dale Carnegie would be more "have you thought about..."
Picked the car up today after the bleed, zero difference.
This is not a pad issue. The pedal will fall on its own with very light pressure. Braking performance at the limit is fine.
I wonder if the ABS system monitors brake system pressure. I suspect you would see a very small increase until you hit the bottom of the pedal.
Audi has their regional rep in next Wednesday. AOA also called me today since I made a complaint about it in the 30 day survey.
Those 30 day surveys are big in the industry and we used to pay very close attention to them when info came in from customers.
This is not a pad issue. The pedal will fall on its own with very light pressure. Braking performance at the limit is fine.
I wonder if the ABS system monitors brake system pressure. I suspect you would see a very small increase until you hit the bottom of the pedal.
Audi has their regional rep in next Wednesday. AOA also called me today since I made a complaint about it in the 30 day survey.
Those 30 day surveys are big in the industry and we used to pay very close attention to them when info came in from customers.
Last edited by MP4.2+6.0; 04-30-2015 at 01:51 PM.
04-30-2015, 03:06 PM
#18
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I don't agree with you, but whatever. Seems like I'm the only guy who actually told you what the front caliper system is and where it came from, but you still just dismiss. Fill out surveys galore; won't change much--as a 35 year owner. The follow on service surveys do some, since they take it in the wallet apparently. But one ding and you're probably somewhat a service hot potato after so use the bullet carefully if ongoing relationship matters. One to one phone calls and e mails are typically what it takes--with some diplomacy--to get attention and some progress. Implied survey threat that seemed in there probably isn't the Dale Carnegie school either.
Meanwhile, pads have a whole lot to do with feel throughout the range if you have driven same vehicle over time with a range of pad choices, including sometimes different choices front to rear. Thus you will find descriptions like linear, progressive, grabby, initial bite and several others that try to capture differences in pad feel. Your own choice of title said "non-linear." And if my description about delta's with ceramic and non-ceramic compounds didn't register, we are in different worlds of brake backgrounds.
ABS theory is candidly ridiculous to me; seems like scope lock just being direct. Thus I tried to give you some new thinking and angles and experience, but you just dismiss it. Meanwhile, zero do do with ABS functions until it starts to lock up. Only other element, is yes it is looking at pressures, but especially it is also looking at rate of change of pressures--that is for the crash guard protective systems to cut in forcefully when it sees an initial stab on brakes and then pressure backing off as ABS cycles, when in a crash scenario it should be held. Meanwhile, I would not go with the ABS ideas myself to Audi higher ups if you are trying to show some technical facility with them; they logically won't buy. Meanwhile, if you go with your own description of pedal falling under slight pressure, that is logically more the brake booster set up (assuming pedal doesn't go toward floor per bad master cylinder) if you want to pursue hardware side. Still zero to do with ABS. There are some weird vacuum scenarios too than can affect booster, maybe yet more esoteric with a blown set up. But those are yet more advanced, set up specific and only occasionally covered in Audi technical literature. If immediately preceding throttle seems to have no relationship, unlikely at play.
As a constructive suggestion meantime, you might go out and try to re-bed the pads on there now. If it were mine with this description, I would go do some spirited runs and sequential 60-0 type stops and heat them up a good amount, followed by some gradual cool down for the following 15+ minutes of drive time. May or may not do something, but might affect it if pad surface glazed over some. After that for when ever the next service re-look is, based on what you said/I read and the system in general, I would be more than anything describbing feel to them and getting them on board same recognition. Then maybe softly nudging on brake booster (and any ancillary parts) review and maybe a pad change out on their nickel in case that shows any improvement. Dale Carnegie would be more "have you thought about..."
Meanwhile, pads have a whole lot to do with feel throughout the range if you have driven same vehicle over time with a range of pad choices, including sometimes different choices front to rear. Thus you will find descriptions like linear, progressive, grabby, initial bite and several others that try to capture differences in pad feel. Your own choice of title said "non-linear." And if my description about delta's with ceramic and non-ceramic compounds didn't register, we are in different worlds of brake backgrounds.
ABS theory is candidly ridiculous to me; seems like scope lock just being direct. Thus I tried to give you some new thinking and angles and experience, but you just dismiss it. Meanwhile, zero do do with ABS functions until it starts to lock up. Only other element, is yes it is looking at pressures, but especially it is also looking at rate of change of pressures--that is for the crash guard protective systems to cut in forcefully when it sees an initial stab on brakes and then pressure backing off as ABS cycles, when in a crash scenario it should be held. Meanwhile, I would not go with the ABS ideas myself to Audi higher ups if you are trying to show some technical facility with them; they logically won't buy. Meanwhile, if you go with your own description of pedal falling under slight pressure, that is logically more the brake booster set up (assuming pedal doesn't go toward floor per bad master cylinder) if you want to pursue hardware side. Still zero to do with ABS. There are some weird vacuum scenarios too than can affect booster, maybe yet more esoteric with a blown set up. But those are yet more advanced, set up specific and only occasionally covered in Audi technical literature. If immediately preceding throttle seems to have no relationship, unlikely at play.
As a constructive suggestion meantime, you might go out and try to re-bed the pads on there now. If it were mine with this description, I would go do some spirited runs and sequential 60-0 type stops and heat them up a good amount, followed by some gradual cool down for the following 15+ minutes of drive time. May or may not do something, but might affect it if pad surface glazed over some. After that for when ever the next service re-look is, based on what you said/I read and the system in general, I would be more than anything describbing feel to them and getting them on board same recognition. Then maybe softly nudging on brake booster (and any ancillary parts) review and maybe a pad change out on their nickel in case that shows any improvement. Dale Carnegie would be more "have you thought about..."
You got a pretty poor attitude for someone who is supposedly a tech expert on here. This is not the first post like this I've seen you post.
As far as pads. I'll take my 20 years of previous experience in Chassis systems, including brakes, and 15 years of track experience to know when it is a pad issue and when it is not.
I bedded the pads as soon as we got the car. It is not a pad issue. There is not an increase in brake pressure in relation to the pedal. That is completely different than an increase in brake pressure where the pad does not perform at certain pressure/temp ranges.
The pedal will fall on its own, that is an actuation problem.
All you did was spew a bunch about parts bin engineering and tell me that the front calipers came off an A8.
04-30-2015, 03:18 PM
#19
AudiWorld Super User
Sorry if you don't like the blunt talk.
You seem to have firm ideas and don't like challenges to them--including the shots at the messenger. Good luck with them and Audi.
You seem to have firm ideas and don't like challenges to them--including the shots at the messenger. Good luck with them and Audi.
04-30-2015, 09:28 PM
#20
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This is not a pad issue.
Good to know bleeding did nothing as I thought.
Everything you have described is spot on. The system feel is not predictable and many slow speed stops jerk to stop. I hate it
I have a late 14 build if that makes any difference.
Good to know bleeding did nothing as I thought.
Everything you have described is spot on. The system feel is not predictable and many slow speed stops jerk to stop. I hate it
I have a late 14 build if that makes any difference.
Who said anything about ABS theory? Canbus has a option for brake pressure sensor, I said wonder if the ABS system has a brake pressure sensor.
You got a pretty poor attitude for someone who is supposedly a tech expert on here. This is not the first post like this I've seen you post.
As far as pads. I'll take my 20 years of previous experience in Chassis systems, including brakes, and 15 years of track experience to know when it is a pad issue and when it is not.
I bedded the pads as soon as we got the car. It is not a pad issue. There is not an increase in brake pressure in relation to the pedal. That is completely different than an increase in brake pressure where the pad does not perform at certain pressure/temp ranges.
The pedal will fall on its own, that is an actuation problem.
All you did was spew a bunch about parts bin engineering and tell me that the front calipers came off an A8.
You got a pretty poor attitude for someone who is supposedly a tech expert on here. This is not the first post like this I've seen you post.
As far as pads. I'll take my 20 years of previous experience in Chassis systems, including brakes, and 15 years of track experience to know when it is a pad issue and when it is not.
I bedded the pads as soon as we got the car. It is not a pad issue. There is not an increase in brake pressure in relation to the pedal. That is completely different than an increase in brake pressure where the pad does not perform at certain pressure/temp ranges.
The pedal will fall on its own, that is an actuation problem.
All you did was spew a bunch about parts bin engineering and tell me that the front calipers came off an A8.