ABS Problem MG ZT-T - Page 14

SD1too · 10th December 2016, 19:55

The sensor is plastic encapsulated! Also, I imagine that the cast iron hub would be a very efficient heatsink.

Quote:

Any pointers from those with more been there, done that experience than I would be greatly appreciated.

Drilling requires care for two reasons: (1) the hole isn't round, it contains a flat towards the base to ensure correct location of the sensor and (2) accurately centreing the drill bit is virtually impossible so start with a small diameter and work upwards. The sensor will break up so it's a slow painstaking process of fishing out bits of plastic.

Simon

larryr123 · 10th December 2016, 23:00

Not sure why this discussion has moved to that of drilling out a sensor.

Both sensors I am fitting are brand new, and the wheel bearing which contains the reluctor ring is also brand new.
All the drilling was done on the old wheel bearing/reluctor ring, which has been removed, discarded and replaced by a new one.

Larry

larryr123 · 11th December 2016, 10:14

MG John, agreed it's good to be open, I misinterpreted it somewhat in relation to my own thread - no worries!

On your post script message re driving a BMW -- some say an MGZT (-T) is a BMW -- or is it a sin to allude to such, just because it's fitted with a BMW common rail diesel engine?

I do wish we had a decent indigenous car industry in the UK - bring back the good old bad old, old days.

OK off to swap the sensors over again to see if the 1st one has any better readings now I have a decent meter.

Larry - PS: Thinking of getting hold of an MGB GT -- anyone any experience of having or driving one of these?

Arctic · 11th December 2016, 10:34

With regards to the drilling of the sensor I would always suspect the magnetic ring first if the front is involved even more so if the speedo is not working on the OS front.

Larry of cause as replaced his with new one, so therefore should not have that worry, but as I say drilling out a sensor is best done by drilling an hole in the centre and using a wood screw to help remove it. please refer to my post 28 link below.

https://www.the75andztclub.co.uk/for...5&postcount=28

PS Larry as you are going to change the front sensor again today, I would and I know it is a fair bit more work but I would remove the disc etc to double check the front bearing for debris and cleanness just a thought, good luck by the way. Arctic

SD1too · 11th December 2016, 12:21

Quote:

Originally Posted by Arctic

... drilling out a sensor is best done by drilling an hole in the centre and using a wood screw to help remove it.

I did try this suggestion of yours Steve but my sensor was so stuck that the wood screw simply tore it to pieces.

At the front, very small pieces fall out of the bottom of the hole. Any that lodge there can be persuaded to fall to the ground by turning the driveshaft slightly or by extracting them with tweezers.

Simon

larryr123 · 11th December 2016, 15:05

Great photos there MGJ -- I thought it was Robert Redford for a minute there!!

Anyhow here's an update.
I changed the sensor back to the 1st new one that I thought was giving low readings.
Not the case, my meter was obviously playing up.
With the new meter I was getting close to 11 volts on the power feed and then when running the signal test I was getting switching between 0.72 volts and 1.78 volts each time and this one picked up all the segments.

So I think the 1st new sensor is a good one, the second sensor is duff.

Tested the car again just to make sure it was not fooling me, but no there is no change it still gives ABS judder at low speed.

So all the wheels have been checked, the multi-plug has been cleaned and the front discs have been changed, 4 new tyres and I'm now at a major road junction because I have absolutely no idea what is causing this ABS judder.

Regards Larry

HarryM1BYT · 11th December 2016, 16:12

Quote:

Originally Posted by larryr123

So all the wheels have been checked, the multi-plug has been cleaned and the front discs have been changed, 4 new tyres and I'm now at a major road junction because I have absolutely no idea what is causing this ABS judder.

Regards Larry

I too am at a loss to explain it, or offer any more suggestions which might be applicable to the ABS itself

Which just leaves suspension and bushes etc..

Clutching at straws- I wonder if there might be a weak or damaged bush, allowing a wheel to go out of alignment enough to trigger the ABS..

SD1too · 11th December 2016, 16:12

Quote:

Originally Posted by larryr123

.. I have absolutely no idea what is causing this ABS judder.

Please forgive me for not trawling through 159 posts Larry, but have you carried out your multimeter test on the rear sensors? If so, maybe time for a drive to see Phil-T4 in MK?

Simon

Arctic · 11th December 2016, 17:43

Quote:

Originally Posted by larryr123

Hi -- I have an MG ZT-T CDti Diesel. Developed an ABS brake pedal judder problem recently and struggling to clear it.
ABS light came on 2 weeks ago and speedo failed. Unplugged ABS fuse and cleaned it and reinstalled it - worked OK, then did it again. Same procedure cleared it.
Since then the ABS light has stayed off but experienced brake pedal judder on braking, as the ABS is coming in erroneously. I confirmed it was an ABS problem by removing fuse again and braking went back to normal, no judder.

Replaced sensor on front right, thinking this would be the cause of an intermittent fault causing the speedo to go off in the first place.
Still had judder at various braking speeds, so took it to garage to be tested. £40 lighter, there was no definite conclusion. Static test showed fault on front right and one on rear right. Cleared faults and took it for a test. Retested it and faults didn't show. Also tried a wheel by wheel test rotating the wheels and recording the variation in voltage - no abnormalities found, they all showed voltages that rose and fell pretty much the same.

Next step - took off rear hubs (that have integrated ABS reluctor rings), cleaned up the rusty back plates (told these could cause the problem), cleaned stub axles and the hubs. Reassembled and it was much improved, ABS not kicking in on general driving, however, it still kicks in at very low speed, almost a few miles per hour.

Quote:

I noticed on the rear Hubs, one hub had what looked like a brass ring on the outside with oval holes cut out at intervals - I assumed this was the reluctor ring, but there wasn't one on the rear nearside hub.

Does this make a difference, i.e. is this brass ring the actual magnetic reluctor ring or is it actually embedded into the hub? As it's been working fine since hubs were last changed in October 2014, I'm at a loss to know what to do next and what could be causing this to judder at low speeds, and yet no ABS light is coming on and no faults recorded.

I guess the ABS is working OK but the signals going back to the ABS control unit are such that it thinks the wheel is locking, but only at low speeds.

Any help welcome.

Hi Larry.
I would suspect one of the rear hub/bearing, i say this because your speedo is working, you have changed both the sensor and the bearing on the front, so in theory the front OS should be ok.

The OS rear as you report as the newer hub/bearing with the oval slotted brass ring, therefore again we could expect this one to be ok, if you are up for a bit more graft i have a rear hub/bearing matching the brass one above which i took of a car recently i fitted it in May of this year, i removed it from the car in October as the owner no longer needed the car.

It is now in my shed and you can have it for the cost of posting, maybe change it over with the one you have fitted at the moment, and see if it makes any difference ? if not then changed or replace the one without the brass ring for the one you removed then see if that makes a difference, other than that i would suggest once more getting it on a T4, if you are interested in giving that a go please send me a PM with your full name and address and i will get the hub sent off to you Arctic.

larryr123 · 11th December 2016, 18:27

Hi Arctic, I changed both rear hubs in 2014. When the fault started a couple months back, I took both off, cleaned up the backplates to make sure no rust and that the sensors were not clogged.

As the T4 reported a fault, the first time I paid the garage in Olney, on the rear nearside, I bit the bullet and bought a new hub and installed this, and that has subsequently passed the multimeter test.
At the time I had the front wheel bearing changed, the T4 test was done again and no faults were recorded.

Larry

11th December 2016, 10:34	#134
Arctic Give to Learn Freelander 2 Join Date: Aug 2010 Location: West Midlands Posts: 18,789 Thanks: 1,155 Thanked 6,407 Times in 3,874 Posts	With regards to the drilling of the sensor I would always suspect the magnetic ring first if the front is involved even more so if the speedo is not working on the OS front. Larry of cause as replaced his with new one, so therefore should not have that worry, but as I say drilling out a sensor is best done by drilling an hole in the centre and using a wood screw to help remove it. please refer to my post 28 link below. https://www.the75andztclub.co.uk/for...5&postcount=28 PS Larry as you are going to change the front sensor again today, I would and I know it is a fair bit more work but I would remove the disc etc to double check the front bearing for debris and cleanness just a thought, good luck by the way. Arctic __________________ Arctic Givology Learn to Give Everything is Achievable ad altiora tendo. Check out our Nano meet dates http://www.midlandsnanomeets.co.uk/ http://www.the75andztclub.co.uk/index.php?thepage=howto " You do the work , we supply the expertise "

10th December 2016, 23:00	#132
larryr123 Avid contributor MG ZT-T Join Date: Aug 2016 Location: larryr123 - Biddenham, Bedfordshire Posts: 224 Thanks: 27 Thanked 19 Times in 17 Posts	Not sure why this discussion has moved to that of drilling out a sensor. Both sensors I am fitting are brand new, and the wheel bearing which contains the reluctor ring is also brand new. All the drilling was done on the old wheel bearing/reluctor ring, which has been removed, discarded and replaced by a new one. Larry

11th December 2016, 10:14	#133
larryr123 Avid contributor MG ZT-T Join Date: Aug 2016 Location: larryr123 - Biddenham, Bedfordshire Posts: 224 Thanks: 27 Thanked 19 Times in 17 Posts	MG John, agreed it's good to be open, I misinterpreted it somewhat in relation to my own thread - no worries! On your post script message re driving a BMW -- some say an MGZT (-T) is a BMW -- or is it a sin to allude to such, just because it's fitted with a BMW common rail diesel engine? I do wish we had a decent indigenous car industry in the UK - bring back the good old bad old, old days. OK off to swap the sensors over again to see if the 1st one has any better readings now I have a decent meter. Larry - PS: Thinking of getting hold of an MGB GT -- anyone any experience of having or driving one of these?

11th December 2016, 15:05	#136
larryr123 Avid contributor MG ZT-T Join Date: Aug 2016 Location: larryr123 - Biddenham, Bedfordshire Posts: 224 Thanks: 27 Thanked 19 Times in 17 Posts	Great photos there MGJ -- I thought it was Robert Redford for a minute there!! Anyhow here's an update. I changed the sensor back to the 1st new one that I thought was giving low readings. Not the case, my meter was obviously playing up. With the new meter I was getting close to 11 volts on the power feed and then when running the signal test I was getting switching between 0.72 volts and 1.78 volts each time and this one picked up all the segments. So I think the 1st new sensor is a good one, the second sensor is duff. Tested the car again just to make sure it was not fooling me, but no there is no change it still gives ABS judder at low speed. So all the wheels have been checked, the multi-plug has been cleaned and the front discs have been changed, 4 new tyres and I'm now at a major road junction because I have absolutely no idea what is causing this ABS judder. Regards Larry

11th December 2016, 18:27	#140
larryr123 Avid contributor MG ZT-T Join Date: Aug 2016 Location: larryr123 - Biddenham, Bedfordshire Posts: 224 Thanks: 27 Thanked 19 Times in 17 Posts	Hi Arctic, I changed both rear hubs in 2014. When the fault started a couple months back, I took both off, cleaned up the backplates to make sure no rust and that the sensors were not clogged. As the T4 reported a fault, the first time I paid the garage in Olney, on the rear nearside, I bit the bullet and bought a new hub and installed this, and that has subsequently passed the multimeter test. At the time I had the front wheel bearing changed, the T4 test was done again and no faults were recorded. Larry