Brake rumble ABS cutting in at below 20mph

Teranchelope · 11th April 2018, 21:42

I have now solved this phenomenon!!
A bit of history first;
After buying my Rover 75 Connoisseur I had an ABS light on all the time and, after new sensor leads, discs, pads etc still had the problem.
Finally, I discovered that the REAR wheel bearings were shot so replaced them with new hubs completely. Fairly easy job and not expensive.
After about 18 months I had the dreaded ABS / brake pedal rumble/grind at low speeds particularly less than 25mph.
Visiting many forums including this one, nobody could solve the problem.
I have now discovered that my new hubs were okay for a period but just before Xmas 2017 the fault developed as have others experienced.
Jacking up the rear (offside first) I felt a small amount of play on the wheel - top to bottom, about 1/2mm no more.
I then undid the hub nut - releasing the locking tab and tweaked the nut a little tighter than it was. Only about 5 degrees. Replacing the lock tab etc and wheel I have had NO further ABS rumble!
Luckily I picked the right side first.
I deduce that I had slightly under torqued the nut at first and a combination of miles and cold weather had exacerbated this. The sensing on the ABS system is VERY sensitive and only detected the false error at low speed due to the dynamics of motion of the rotation etc. i.e. More sensitive at lower triggering.
So, anybody having this fairly common problem look no further than new hubs and/or correct torquing of the nuts!
Happy Days!

Mike Noc · 11th April 2018, 22:20

Another thing that can cause a slight increase in the air gap between the rear ABS sensors and the magnetic reluctors is a build up of corrosion under the sensor mounting lug.

11th April 2018, 21:42	#1
Teranchelope Regular poster Rover 75 Facelift 54 plate saloon Join Date: Feb 2016 Location: Pulborough Posts: 70 Thanks: 15 Thanked 4 Times in 4 Posts	Brake rumble ABS cutting in at below 20mph I have now solved this phenomenon!! A bit of history first; After buying my Rover 75 Connoisseur I had an ABS light on all the time and, after new sensor leads, discs, pads etc still had the problem. Finally, I discovered that the REAR wheel bearings were shot so replaced them with new hubs completely. Fairly easy job and not expensive. After about 18 months I had the dreaded ABS / brake pedal rumble/grind at low speeds particularly less than 25mph. Visiting many forums including this one, nobody could solve the problem. I have now discovered that my new hubs were okay for a period but just before Xmas 2017 the fault developed as have others experienced. Jacking up the rear (offside first) I felt a small amount of play on the wheel - top to bottom, about 1/2mm no more. I then undid the hub nut - releasing the locking tab and tweaked the nut a little tighter than it was. Only about 5 degrees. Replacing the lock tab etc and wheel I have had NO further ABS rumble! Luckily I picked the right side first. I deduce that I had slightly under torqued the nut at first and a combination of miles and cold weather had exacerbated this. The sensing on the ABS system is VERY sensitive and only detected the false error at low speed due to the dynamics of motion of the rotation etc. i.e. More sensitive at lower triggering. So, anybody having this fairly common problem look no further than new hubs and/or correct torquing of the nuts! Happy Days!

11th April 2018, 22:20	#2
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,551 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Another thing that can cause a slight increase in the air gap between the rear ABS sensors and the magnetic reluctors is a build up of corrosion under the sensor mounting lug.