Feels like brakes are slipping
#1
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Thread Starter
Feels like brakes are slipping
This started happening at the same time the CEL came on (P0136 - apparently O2 sensor, apparently unrelated) on my 2000 E320 4matic. When I brake, as the car gets to near stopping - certainly under 15 MPH - I feel a little "slip" in the brakes. It feels a lot like the sensation of the traction control kicking in during an over-aggressive turn on wet roads, but now it happens every time I stop, even if I'm stopping very gently.
Any ideas? Is there any way this is related to the P0136 code? It started at pretty much exactly the same time, but could just be a coincidence.
Any ideas? Is there any way this is related to the P0136 code? It started at pretty much exactly the same time, but could just be a coincidence.
#2
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1922 Ford Model T / no OBD
Are you sure it is not transmission disengaging?
Observe rpm at that moment.
Observe rpm at that moment.
#3
Check front wheel hub ABS rings for a fracture
On the rear check outer drive shaft ABS ring for same thing
Or if you can get diagnostic plugged in on ABS live data it will pick up the bad ABS ring or sensor but only at low speed as you pull up to a stop
On the rear check outer drive shaft ABS ring for same thing
Or if you can get diagnostic plugged in on ABS live data it will pick up the bad ABS ring or sensor but only at low speed as you pull up to a stop
#4
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#5
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1922 Ford Model T / no OBD
With years of driving with 5-speed I did not notice that, but new to us 7-sp coupled to diesel makes quite jerking at low speeds.
So I start paying attention what 5-sp on older car does and to my disbelieve, it is progressively downshifting while you slow down, helping with braking.
Just with different gearing, it is harder to notice on 5 sp than on 7sp.
Just because of that I switched 7sp transmission to C mode, what is not the best when you drive in the mountains.
#6
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Thread Starter
I've been considering a bluetooth device to gather real-time info. Is there anything specific I should look for or avoid? I'm mostly interested in gathering diagnostic info like this, and would be using my iPhone or iPad.
#7
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Thread Starter
Okay, after my last post, I went out for a long drive and paid attention to RPM and the slipping feeling. It does, in fact, appear to be sync'd with the downshifts while I'm stopping. So, why would I suddenly be feeling those via the brake pedal.
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#8
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it's challenging for me to really know what you're experiencing because you're
doing your best to describe a feeling...a sensation using the best words you can
to paint a picture of what the car is actually through.
if it is what I'm envisioning, it may simply be the transmission's synchromesh
failing to match the handoff between gears properly. so, when slowing down,
the transmission normally would downshift during predetermined revs and
smoothly change gears
but in your case, the handoff between gears is done with too great a difference
between speed/revs and you feel jerkiness. is that correct?
try resetting the adaptive transmission and get back to us. (scroll down to
"Transmission, ECU resetting")
if you're very lucky, that may solve the issue. if not (at worse) the tranny may need
to be worked on. i had that done but it was under extended warranty so it was at
no cost. when i brought it back a 3rd time, they replaced the transmission
doing your best to describe a feeling...a sensation using the best words you can
to paint a picture of what the car is actually through.
if it is what I'm envisioning, it may simply be the transmission's synchromesh
failing to match the handoff between gears properly. so, when slowing down,
the transmission normally would downshift during predetermined revs and
smoothly change gears
but in your case, the handoff between gears is done with too great a difference
between speed/revs and you feel jerkiness. is that correct?
try resetting the adaptive transmission and get back to us. (scroll down to
"Transmission, ECU resetting")
if you're very lucky, that may solve the issue. if not (at worse) the tranny may need
to be worked on. i had that done but it was under extended warranty so it was at
no cost. when i brought it back a 3rd time, they replaced the transmission
#9
Junior Member
Thread Starter
it's challenging for me to really know what you're experiencing because you're
doing your best to describe a feeling...a sensation using the best words you can
to paint a picture of what the car is actually through.
if it is what I'm envisioning, it may simply be the transmission's synchromesh
failing to match the handoff between gears properly. so, when slowing down,
the transmission normally would downshift during predetermined revs and
smoothly change gears
but in your case, the handoff between gears is done with too great a difference
between speed/revs and you feel jerkiness. is that correct?
try resetting the adaptive transmission and get back to us. (scroll down to
"Transmission, ECU resetting")
if you're very lucky, that may solve the issue. if not (at worse) the tranny may need
to be worked on. i had that done but it was under extended warranty so it was at
no cost. when i brought it back a 3rd time, they replaced the transmission
doing your best to describe a feeling...a sensation using the best words you can
to paint a picture of what the car is actually through.
if it is what I'm envisioning, it may simply be the transmission's synchromesh
failing to match the handoff between gears properly. so, when slowing down,
the transmission normally would downshift during predetermined revs and
smoothly change gears
but in your case, the handoff between gears is done with too great a difference
between speed/revs and you feel jerkiness. is that correct?
try resetting the adaptive transmission and get back to us. (scroll down to
"Transmission, ECU resetting")
if you're very lucky, that may solve the issue. if not (at worse) the tranny may need
to be worked on. i had that done but it was under extended warranty so it was at
no cost. when i brought it back a 3rd time, they replaced the transmission
#10
MBWorld Fanatic!
so when you say that it feels like it is slipping, does that mean that when you
step on the brake, you're not feeling a corresponding and proportionate braking
action...and that the car's forward motion is not arrested?
(still trying to picture this, obviously)
if you had a ball bearing on the floor, when the sensation is felt, what action
are you taking and which direction would the bearing roll?
step on the brake, you're not feeling a corresponding and proportionate braking
action...and that the car's forward motion is not arrested?
(still trying to picture this, obviously)
if you had a ball bearing on the floor, when the sensation is felt, what action
are you taking and which direction would the bearing roll?
#11
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1922 Ford Model T / no OBD
Don't rule out Placebo effect.
As I said, I drove 5-sp in different cars for over 10 years and never noticed the transmission braking. Now once I am aware it is happening, I feel it all the time.
Funny on latest job I was coming from intersection where after left turn I had like 200 yard to next light that was timed red for me all the time.
So knowing the timing I was simply letting the car roll down the sloppy street. The 5sp transmission would slow down the car till about 8 mph and then disengage, giving sensation of accelerating.
As I said, I drove 5-sp in different cars for over 10 years and never noticed the transmission braking. Now once I am aware it is happening, I feel it all the time.
Funny on latest job I was coming from intersection where after left turn I had like 200 yard to next light that was timed red for me all the time.
So knowing the timing I was simply letting the car roll down the sloppy street. The 5sp transmission would slow down the car till about 8 mph and then disengage, giving sensation of accelerating.
Last edited by kajtek1; 09-04-2016 at 10:45 PM.
#12
Junior Member
Thread Starter
so when you say that it feels like it is slipping, does that mean that when you
step on the brake, you're not feeling a corresponding and proportionate braking
action...and that the car's forward motion is not arrested?
(still trying to picture this, obviously)
if you had a ball bearing on the floor, when the sensation is felt, what action
are you taking and which direction would the bearing roll?
step on the brake, you're not feeling a corresponding and proportionate braking
action...and that the car's forward motion is not arrested?
(still trying to picture this, obviously)
if you had a ball bearing on the floor, when the sensation is felt, what action
are you taking and which direction would the bearing roll?
The feeling from the brake pedal is a very brief (less than a second), very fast vibration. The closest I can describe is that it's the same sensation I feel in the pedal if the tires are slipping and the ESP kicks in.
#13
MBWorld Fanatic!
i'm not sure how helpful it really is to guess and throw in the presumed sensation of ESP
(vs, for example, ABS), or that the tires are slipping (they're not, as far as I know) at
this point. what is more important is that you describe the observation (frequency,
speed, consistent repeat under X circumstances, kinesthetic feedback etc).
(vs, for example, ABS), or that the tires are slipping (they're not, as far as I know) at
this point. what is more important is that you describe the observation (frequency,
speed, consistent repeat under X circumstances, kinesthetic feedback etc).
#14
Junior Member
Thread Starter
so when you say that it feels like it is slipping, does that mean that when you
step on the brake, you're not feeling a corresponding and proportionate braking
action...and that the car's forward motion is not arrested?
(still trying to picture this, obviously)
if you had a ball bearing on the floor, when the sensation is felt, what action
are you taking and which direction would the bearing roll?
step on the brake, you're not feeling a corresponding and proportionate braking
action...and that the car's forward motion is not arrested?
(still trying to picture this, obviously)
if you had a ball bearing on the floor, when the sensation is felt, what action
are you taking and which direction would the bearing roll?
To use the ball bearing, it feels like when I'm stopping the ball bearing would be moving forward steadily (as it would under braking power), then would slow its forward momentum (during the "slipping"), then resume. The pause would be maybe half a second, at most. As I said before, I'm not sure that pause would actually happen, but it feels like it would.
I think this might be entirely in the brake pedal since my wife didn't notice anything from the passenger's seat, but she wasn't trying to feel anything either. I'll get her to pay attention for anything odd next time she's in the car with me.
#15
Junior Member
Thread Starter
Don't rule out Placebo effect.
As I said, I drove 5-sp in different cars for over 10 years and never noticed the transmission braking. Now once I am aware it is happening, I feel it all the time.
Funny on latest job I was coming from intersection where after left turn I had like 200 yard to next light that was timed red for me all the time.
So knowing the timing I was simply letting the car roll down the sloppy street. The 5sp transmission would slow down the car till about 8 mph and then disengage, giving sensation of accelerating.
As I said, I drove 5-sp in different cars for over 10 years and never noticed the transmission braking. Now once I am aware it is happening, I feel it all the time.
Funny on latest job I was coming from intersection where after left turn I had like 200 yard to next light that was timed red for me all the time.
So knowing the timing I was simply letting the car roll down the sloppy street. The 5sp transmission would slow down the car till about 8 mph and then disengage, giving sensation of accelerating.
#16
Junior Member
Thread Starter
i'm not sure how helpful it really is to guess and throw in the presumed sensation of ESP
(vs, for example, ABS), or that the tires are slipping (they're not, as far as I know) at
this point. what is more important is that you describe the observation (frequency,
speed, consistent repeat under X circumstances, kinesthetic feedback etc).
(vs, for example, ABS), or that the tires are slipping (they're not, as far as I know) at
this point. what is more important is that you describe the observation (frequency,
speed, consistent repeat under X circumstances, kinesthetic feedback etc).
#17
Junior Member
Thread Starter
Well, my wife has been sick, so we haven't taken a drive together. However, I have confirmed that I can actually hear (not just feel) whatever it is. I hear it as almost a soft groan that lasts just as briefly as the vibration I feel in the brake pedal.
#18
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1922 Ford Model T / no OBD
The truth is that with such delicate symptoms we can guess forever with no guarantee to confirm guess this way or the other.
SOP in such case is to eliminate easy things that should be taken care about anyway.
So I would do standard service even if it is not yet due.
-transmission ATF change and pilot bushing replacement. Add TCU washing if you notice traces of leak
-brake fluid flush and pads replacement even if you have them new
-ABS sensors and reluctor rings careful inspection
- you mention O2 sensors, but were they replaced? How old are spark plugs?
SOP in such case is to eliminate easy things that should be taken care about anyway.
So I would do standard service even if it is not yet due.
-transmission ATF change and pilot bushing replacement. Add TCU washing if you notice traces of leak
-brake fluid flush and pads replacement even if you have them new
-ABS sensors and reluctor rings careful inspection
- you mention O2 sensors, but were they replaced? How old are spark plugs?
Last edited by kajtek1; 09-10-2016 at 01:11 AM.