[speirsy]

Hi.
When out on the open road, my ABS seems to be activating for no reason, though the ABS light does not. I slow the car gently down from 50 mph, and around 40 mph, I get that ABS pumping feeling through my brake pedal. So I go a little harder on the brake, then the ABS seems to cut out and normal, and also heavy braking kicks in. It was very worrying at first, but I've got the hang of it now to some extent.  But slowing down is never smooth, and passengers think my driving is terrible!
I've had various garages look at it. One guy wiped the computer fault codes. Weeks later, he tested again and found no fault, so he was powerless to tackle the problem as he didn't know where to start. Changing all the sensors and wheel bearings would cost hundreds and could ultimately prove pointless. It could be the ABS pump which could take the repair cost into 4 figures. He did say that there is no risk of the brakes failing catastrophically, so I can continue to drive it safely. However, it’s something I’d like to get sorted out efficiently.
I’d rather not take it to a dealer who would charge an arm and a leg to tell me what I already know.
My question is, has this fault been flagged before? Is Hyundai aware of it? Can you help?
Thanks in advance for your replies.

[eye30]

I'm not mechanically minded but the following may help our experts provide pointers.

Can you provide some details as to car age, mileage, service record, petrol or diesel etc etc.

Also, whether any work has been done in brakes such as new pads.

Has it recently had an MOT as you may have been given the braking efficiency readout.
Does this indicate possible issues.

[Lorian]

Is the ABS light on the dash flashing when this happens?

I presume you have checked your tyre pressures?

This vaguely rings a bell as being seen by someone years ago

[speirsy]

I got a diagnosis from the Hyundai dealer nearby. The ABS speed sensor ring is cracked. It wraps around the drive shaft near the CV joint. Unfortunately, it cannot be ordered on its own, and the whole driveshaft, and ring assembly must be replaced which costs £550. Or so the dealer says.
I hope to find an independent mechanic who can offer a cheaper solution. I need to do further research. This must have come up here before. I would be grateful to hear from anyone who has experience of this issue.

[PGN I30]

FRONT ABS RELUCTOR RING Fits HYUNDAI i30 [2007-2019] | eBay

[Lorian]

I thought they were a press fit - heat up and push on sort of thing. but I've not looked at one in some time. will need to take the driveshaft off though.

Just to give some minor evidence towards this

FRONT ABS RELUCTOR RING Fits HYUNDAI i30 [2007-2019] | eBay - keep in mind thats just the first seller I spotted and their feedback is not perfect.

[speirsy]

I found a driveshaft and ring online for £110 and my mechanic will fit it for £50.
Thanks for the reluctor posts above. It would be nice to have the job done sub £100, changing just the ring, but I’d struggle to find someone who is happy to bang away at the existing drive shaft, given that I don’t have absolute clarity if it’s even possible. Thanks.

[speirsy]

This problem is sorted. My vibrating brake pedal is now operating properly.
The reluctor ring / ABS speed sensor ring, which I was told only came part of the drive shaft assembly, was successfully swapped on the existing drive shaft for £50.  The ring cost £7. this starkly contrasts the advice from the Hyundai dealership who wanted £750 to swap the whole drive shaft.
lessons learned
I needn't have bothered searching for and buying the whole driveshaft.
Some independent garages will go the extra mile and beyond just swapping like for like by reconditioning existing parts from the car with heat and a hammer.
One thing the dealership did do right was diagnose the problem propperly. I believe this is due to them having better software when plugging into the car's computer. The 3 independents I tried who put their diagnostic machine on the car did not detect the issue. Perhaps their software is inferior to the dealership's.
Use a vim number when buying parts online.

[JpHyundaiFan]

this starkly contrasts the advice from the Hyundai dealership who wanted £750 to swap the whole drive shaft.

The typical customer service fault: 1) offering something extra the customer does not need (not focusing to fix only what is needed), 2) overcharging

[asathorny]

I got a diagnosis from the Hyundai dealer nearby. The ABS speed sensor ring is cracked. It wraps around the drive shaft near the CV joint. Unfortunately, it cannot be ordered on its own, and the whole driveshaft, and ring assembly must be replaced which costs £550. Or so the dealer says.
I hope to find an independent mechanic who can offer a cheaper solution. I need to do further research. This must have come up here before. I would be grateful to hear from anyone who has experience of this issue.

That sounds like the mechanic who adviced me when I had a mirror glass broken that I had to buy the whole mirrow.  I went on line and bought a new mirrow for £9, flicked out what was left of the cracked one the pressed fitted the new one.  Voila, job sorted £9.
GOOD LUCK