Abs

Ascen · 9th October 2016, 00:03

I had the issue of the ABS grinding effect when lightly braking at slow speeds, and my speedo was a little irratic, so I determined it was the driver side front ABS cable.

Had fun replacing that today, completely stuck inside... drill, screwdriver, hammer and a couple hours later I managed to remove it all (I think, I hope) and fitted the new cable.

Every time I pressed the brake the grinding effect happened! On the main road the ABS light kicked in and also my speedo was only hovering at 40 when was doing 60. Although the brakes were fine after the light came on, so I assume the whole thing was disabled.

Is there something in particular that may have gone wrong? or may it just be a dodgy cable?

Ascen · 10th October 2016, 12:49

Update
I had a second look and it seems there's a bit of plastic from the old sensor which had fallen behind and into the wheel.

Would this be the cause of the issue, or does it pick the signal from the side? In which case the new sensor may be at fault.

Ascen · 15th October 2016, 14:54

New sensor fitted, I also removed 2 bits of plastic debris down where the sensor fits and rotating the wheel.

Still same issue.

There may still be some debris left in there, but none is appearing anymore as I am rotating the wheel so they may be stuck at the bottom. What is the approach to get access into here?

Or could it be something else?

SD1too · 15th October 2016, 17:46

Mark; I'm replacing an ABS wheel sensor at the moment as well. I believe that to get full access the hub needs to be separated from the driveshaft. However I'm not entirely convinced that the symptoms you describe point to a wheel sensor. I think that in your shoes I would seek the diagnostic assistance of a T4.

Simon

Ascen · 15th October 2016, 20:50

ABS sensor disconnected and the symptoms vanish, except speedo is completely gone of course.

The symptoms got worse since I replaced the ABS cable which leads me to believe the original sensor was at fault, but now due to the difficulty of removal the fault lies elsewhere. ie the debris left behind.

I've read around and seems worst case scenario the wheel bearing will need replacing. Will check the fault codes tomorrow.

max1 · 15th October 2016, 20:56

I recently cured my abs problem after many months, by replacing the complete hub assembly.
However prior to this I had an abs light on and speedo failure, so replaced the drivers side sensor by drilling out the old sensor. In doing this, the last little bit of the sensor dropped into the bearing.
I replaced the sensor and immediately had the abs operating at low speed, but with no warning light. A week later the abs failed, warning light on, and no speedo ( again ).

I again removed the sensor, this time by extracting it complete, and fitted a new one.
Still warning light on and no speedo, at this point I decided to replace the hub assembly with a known working replacement. Now done and all working.

On inspecting the removed hub, it would appear that the small piece that dropped into the bearing, had , after fitting a new sensor, became trapped between the sensor and the magnetic ring.
This small piece in a very short space of time, had worn away totally the soft magnetic ring.
Also, as the sensor detects the ring from the side of the sensor, and not the tip, as I always thought, I don't think the issue arises about how far the sensor sits into the bearing, as long as it is seated flat.

My advice would be to always try to extract on old sensor complete, and avoid any contamination of the bearing.

Hope this may help anyone with abs problems.

Arctic · 16th October 2016, 00:46

Hi Mark.
Pics of the two below

for you, nice to know when I saw you yesterday that the hub and sensor are working as they should still after your holidays

max1 · 16th October 2016, 06:04

Thanks Steve, it will make my post make more sense with the photos.

SD1too · 16th October 2016, 07:49

Quote:

Originally Posted by Ascen

ABS sensor disconnected and the symptoms vanish, except speedo is completely gone of course.

With any sensor disconnected your ABS system would shut down wouldn't it? Does that prove that the OSF sensor is at fault?

Simon

Porkpie · 26th October 2016, 16:08

Any updates on this?
I too have the same problem but my speedo works.

9th October 2016, 00:03	#1
Ascen Regular poster MG ZT Join Date: Jan 2016 Location: York Posts: 40 Thanks: 3 Thanked 3 Times in 3 Posts	Abs I had the issue of the ABS grinding effect when lightly braking at slow speeds, and my speedo was a little irratic, so I determined it was the driver side front ABS cable. Had fun replacing that today, completely stuck inside... drill, screwdriver, hammer and a couple hours later I managed to remove it all (I think, I hope) and fitted the new cable. Every time I pressed the brake the grinding effect happened! On the main road the ABS light kicked in and also my speedo was only hovering at 40 when was doing 60. Although the brakes were fine after the light came on, so I assume the whole thing was disabled. Is there something in particular that may have gone wrong? or may it just be a dodgy cable?

15th October 2016, 17:46	#4
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,376 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Mark; I'm replacing an ABS wheel sensor at the moment as well. I believe that to get full access the hub needs to be separated from the driveshaft. However I'm not entirely convinced that the symptoms you describe point to a wheel sensor. I think that in your shoes I would seek the diagnostic assistance of a T4. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

10th October 2016, 12:49	#2
Ascen Regular poster MG ZT Join Date: Jan 2016 Location: York Posts: 40 Thanks: 3 Thanked 3 Times in 3 Posts	Update I had a second look and it seems there's a bit of plastic from the old sensor which had fallen behind and into the wheel. Would this be the cause of the issue, or does it pick the signal from the side? In which case the new sensor may be at fault.

15th October 2016, 14:54	#3
Ascen Regular poster MG ZT Join Date: Jan 2016 Location: York Posts: 40 Thanks: 3 Thanked 3 Times in 3 Posts	New sensor fitted, I also removed 2 bits of plastic debris down where the sensor fits and rotating the wheel. Still same issue. There may still be some debris left in there, but none is appearing anymore as I am rotating the wheel so they may be stuck at the bottom. What is the approach to get access into here? Or could it be something else?

15th October 2016, 20:50	#5
Ascen Regular poster MG ZT Join Date: Jan 2016 Location: York Posts: 40 Thanks: 3 Thanked 3 Times in 3 Posts	ABS sensor disconnected and the symptoms vanish, except speedo is completely gone of course. The symptoms got worse since I replaced the ABS cable which leads me to believe the original sensor was at fault, but now due to the difficulty of removal the fault lies elsewhere. ie the debris left behind. I've read around and seems worst case scenario the wheel bearing will need replacing. Will check the fault codes tomorrow.

15th October 2016, 20:56	#6
max1 Avid contributor Rover 75 Tourer cdt Join Date: Sep 2014 Location: Wolverhampton Posts: 176 Thanks: 51 Thanked 57 Times in 39 Posts	I recently cured my abs problem after many months, by replacing the complete hub assembly. However prior to this I had an abs light on and speedo failure, so replaced the drivers side sensor by drilling out the old sensor. In doing this, the last little bit of the sensor dropped into the bearing. I replaced the sensor and immediately had the abs operating at low speed, but with no warning light. A week later the abs failed, warning light on, and no speedo ( again ). I again removed the sensor, this time by extracting it complete, and fitted a new one. Still warning light on and no speedo, at this point I decided to replace the hub assembly with a known working replacement. Now done and all working. On inspecting the removed hub, it would appear that the small piece that dropped into the bearing, had , after fitting a new sensor, became trapped between the sensor and the magnetic ring. This small piece in a very short space of time, had worn away totally the soft magnetic ring. Also, as the sensor detects the ring from the side of the sensor, and not the tip, as I always thought, I don't think the issue arises about how far the sensor sits into the bearing, as long as it is seated flat. My advice would be to always try to extract on old sensor complete, and avoid any contamination of the bearing. Hope this may help anyone with abs problems.

16th October 2016, 06:04	#8
max1 Avid contributor Rover 75 Tourer cdt Join Date: Sep 2014 Location: Wolverhampton Posts: 176 Thanks: 51 Thanked 57 Times in 39 Posts	Thanks Steve, it will make my post make more sense with the photos.

26th October 2016, 16:08	#10
Porkpie Regular poster Rover 75 Saloon Join Date: Jan 2016 Location: Saltburn by the Sea Posts: 63 Thanks: 65 Thanked 8 Times in 8 Posts	Any updates on this? I too have the same problem but my speedo works.