Page 1 of 1

ABS kicking in every minute or so-need help please

Posted: Tue Jul 14, 2020 10:47 am
by puma78
Hi, I'm new to this site, I have a 1.7 2001 puma. Last year not long after hitting a pot hole i noticed the ABS/Traction Control lights on, on the dash. I has replaced both the front sensors which put the lights out, but then after approx 30 secs of driving the ABS pump would start making a loud noise and the brake pedal would be bouncing. When applying the brakes at this point they would sound like they are grinding, then would go back to normal.

I replaced the ABS pump (2nd hand one) but same problem although the pump noise was reduced with this replacement. Over the several months i have since replaced the sensors again, 1 at a time, nothing changed. The brakes will work absolutely fine if i unplug 1 or both sensors (lights on dash will return though)

Ive taken it to a garage to be checked and they can't find anything wrong, their diagnostic machine picked up an abs sensor fault for a split 2nd, this was when i replaced them again.

I drove the car last weekend after swapping 1 of the sensors with a previous sensor, although the pump noise seems to be gone i can still feel the peddle bouncing.

I'm stumped now, any ideas will be greatly appreciated. P.S also will be for sale once this problem is finally resolved.

ABS kicking in every minute or so-need help please

Posted: Tue Jul 14, 2020 11:59 am
by red
Have you checked the tone ring whilst changing the sensors? Maybe one has been damaged or corroded?

Welcome to the site.
Wild E. Coyote wrote:
Thu May 30, 2019 4:52 am
Yes, sound like ABS. Check the sensor to tone ring gap. This behaviour, grinding to a stop is usually a sign of misaligned or slightly damaged tone ring (few notches are bent in). As the speed decreases so the signal weakens and at the point of irregularity it will break down i.e. disappear. The ABS unit detects that as a wheel lock up and kicks in.
I had the same problem at first with my rear disc conversion as one sensor was out of place by less than 1 mm (radially) and the pickup of the signal was not good and the unit would pass self test, but as the car would slow down, some grinding would occur.
The sensor to ring gap should be 0,6 mm (0,4 to 0,8 is tolerated, but aim for 0,6 mm).
The ABS is easily checked with Forscan. There is a live speed readout function and it will tell you which wheel is in problem.

ABS kicking in every minute or so-need help please

Posted: Wed Jul 15, 2020 10:20 am
by puma78
Thank you very much for that, that would make sense as my father's pal was changing the sensors over for me the first tiem round and he was leavering the sensors off with a screwdriver and im certain was against the ring so likely one or both is very likely bent/buckled. When i changed the sensors the 2nd time i rubbed down the rings with sandpaper to get the rust off and never noticed any damage but then again i wasn't looking either. I'll check them at the weekend again.
thanks again guys, much appreciated.

ABS kicking in every minute or so-need help please

Posted: Wed Jul 15, 2020 11:44 am
by Wild E. Coyote
The Forscan option is the easiest way of diagnosing. (https://forscan.org) it is free. You will need an OBD reader. Any cheap chinese clone (USB recommended) will work. The complete how to is on web page of Forscan...

ABS kicking in every minute or so-need help please

Posted: Thu Jul 16, 2020 11:06 am
by puma78
Thank you for that suggestion Wild E. Coyote, ive had a look at FORscan and downloaded the app but i think my OBDii reader is too basic, it simply plugs into the OBD socket on the car, nothing else on it unfortunately, so i'll need to check the rings the old fashioned way. thanks anyway, useful app none the less with the correct equipment.

ABS kicking in every minute or so-need help please

Posted: Tue Jul 21, 2020 10:27 am
by puma78
Hi again, i don't have the technology to use FORscan so i have has a look at the rings and rubbed them down with a wire brush then sandpaper and a microfibre cloth afterwards to get rid of any rust dust and wiped the magnetic strips on both sensors too, while cleaning the ring i was doing this while till on the car and using the sensors as a guide to check for any bend/buckle in the rings too and found nothing wrong and yet after doing this took it for a drive and the ABS is still kicking in randomly.

Any other suggestions/ideas? I have someone coming tomorrow to view it so i don't have a lot of time to fix this.

while nosing around on this site there has been mention of air getting trapped in the abs pump, i did swap that over but someone pumped the brake peddle before i got the chance the bleed the brakes, peddle ofcourse went to the floor. I was only able to bleed the brakes from both front nipples only (rears were seized) i do have a firm peddle though. If there was air trapped anywhere in the system 1-would i have a solid brake peddle? 2- can this be the cause of the abs kicking in randomly?

ABS kicking in every minute or so-need help please

Posted: Tue Jul 21, 2020 1:07 pm
by tuonokid
Hi Mate
Whereabouts are you? If you're near me your welcome to come over and I'll do a Forscan test for you I'm in Huddersfield W Yorks.
Barry

ABS kicking in every minute or so-need help please

Posted: Tue Jul 21, 2020 1:16 pm
by puma78
tuonokid wrote:
Tue Jul 21, 2020 1:07 pm
Hi Mate
Whereabouts are you? If you're near me your welcome to come over and I'll do a Forscan test for you I'm in Huddersfield W Yorks.
Barry
Thank you very much for that offer but unfortunately im up in Fife, central Scotland.

ABS kicking in every minute or so-need help please

Posted: Thu Jul 23, 2020 11:33 am
by puma78
Hi again, really sorry to be a pain, i know i'm a complete amateur but I'll have a go at anything. Just thinking back to my first reposonse to this post. Wild E.Coyote advised the following "The sensor to ring gap should be 0,6 mm (0,4 to 0,8 is tolerated, but aim for 0,6 mm).
The ABS is easily checked with Forscan. There is a live speed readout function and it will tell you which wheel is in problem."

Thinking back to this, i'm almost certain the gap between the sensor and the ring is much greater, at a guestimate i would say the gap is approx 2mm, certainly over 1mm anyway but the sensors are in as far as the can go and seems to be the case for both fronts. I never saw the original sensor gap as my dad's pal done them the first time. I have bought 2 different sets of sensors (bought pairs so both sides the same) from 2 different manufacturers and both sets went in the same distance. I may be being stupid, but is it possible that both rings may have been pushed back into the hub if they were being levered to get the old ones out? But the rings don't appear to be bent or bucked.

Thanks again for taking the time read and respond.

ABS kicking in every minute or so-need help please

Posted: Thu Jul 23, 2020 3:22 pm
by Wild E. Coyote
Using feeler gauge should be possible to measure the gap. At least at front as it is doable there without problems. If you have replaced sensors, have you cleaned the hubs so the sensor can go in all the way?
The rings could be deformed, it is very easy to do when you are taking out the sensors which are rusted as h_ll in...

ABS kicking in every minute or so-need help please

Posted: Thu Jul 23, 2020 4:01 pm
by puma78
:roll: you know what! I was thought about using a feeler gauge just seconds after posting this and also I thought I will remove the sensors and rub the bit the fit into, to get any rust/dirt and see what happens. If this doesn’t resolve then I think it’s time to give up as it’s coming on for a year now since I noticed this problem.

ABS kicking in every minute or so-need help please

Posted: Fri Jul 31, 2020 10:26 am
by puma78
Hi again, i have cleaned the hub and the sensors and the rings too, the gap is approx 1-2mm and looking at the rings im almost certain they are straight. I'm just in the past few minutes bought a forscan cable to run from the OBDii plug into a laptop and hopefully this will work and tell me whats wrong. The is still 1 thing niggling me though. I have read in many forums that the ABS pump needs to be bled electronically, so if air is in the pump/module could this be causing the abs to come on randomly?

ABS kicking in every minute or so-need help please

Posted: Fri Jul 31, 2020 5:02 pm
by Wild E. Coyote
There is a procedure to bleed the ABS unit by diagnostic equipment if it traps some air. However, if you fill the system properly and pressurize it while adding the brake fluid, it should drive the air out