ABS (Horrible sounding noise)

[Tony]

I have been experiencing a horrible noise from my brakes on a few occasions over the years - almost like when the disk pads are gone, and are chowing the disks. There is also a sort of vibration on the brake pedal.
Recently, I have made a connection with wet tar and the need to brake suddenly - the same noise and pedal feedback is there, and the car does not stop well at all.
Graham Cummings recently serviced my Troll and found a fault with the load sensor on the back axle. He discovered that I have only been braking on the front wheels for who knows how long! Hopefully this will sort out the stopping distance in the wet, but when we did a test braking on sand to show me that all 4 wheels were actually stopping, the brakes made the same sound with the same vibration on the pedal. Graham assures me that this is normal on all Patrols.
I would just like to find out if any of you guys out there have had similar experiences - I still need to see how she behaves in the wet.

[Jorrie]

I would believe Graham!

[IanT]

That is the abs kicking in, sounds like brake pads but works brilliantly, have been on a fue Skid pans and used it unbealeable!!

[Clem]

I have been experiencing a horrible noise from my brakes on a few occasions over the years - almost like when the disk pads are gone, and are chowing the disks. There is also a sort of vibration on the brake pedal.
Recently, I have made a connection with wet tar and the need to brake suddenly - the same noise and pedal feedback is there, and the car does not stop well at all.
Graham Cummings recently serviced my Troll and found a fault with the load sensor on the back axle. He discovered that I have only been braking on the front wheels for who knows how long! Hopefully this will sort out the stopping distance in the wet, but when we did a test braking on sand to show me that all 4 wheels were actually stopping, the brakes made the same sound with the same vibration on the pedal. Graham assures me that this is normal on all Patrols.
I would just like to find out if any of you guys out there have had similar experiences - I still need to see how she behaves in the wet.

Tony, its 100% as it should be. The manual for my GRX even describes exactly that. My Mercedes also does exactly the same under hard braking. It's the ABS.

[Stefan]

Hi Tony,

Does it do this all the time or only under very hard braking?

[Tony]

Howzit Stefan, - firstly, I drive just like an "ou ballie" so hard braking is one thing that I never do. Having said that, on a few occasions (on wet tar) I braked a little harder than normal when the robots changed and I decided to do the right thing and stop! This is when I had the loud noise, and, more importantly the fact that the car did'nt stop - it felt almost like the wheels locked and I was sliding. Tyres are new Cooper ST MAXX's. I have also heard this noise on about four other occasions over the past five years in dry weather and on different surfaces, but never associated with hard braking.
Graham did pick up that the car has been braking only on the front which probably explains the bad stopping distances in the wet.
My concern is that ABS surely only kicks in with hard braking - or am I mistaken and it's there at all times, especially with wheels on uneven surfaces.
Regards
Tony

[Tinus lotz]

Tony when swartkops has a track day again we must take a few patrols there ....me and peter had great fun there before in your plat karre then u can test it properly we can even speak to graham to bring his patrol and then we can all have a look and some fun

[Clem]

Howzit Stefan, - firstly, I drive just like an "ou ballie" so hard braking is one thing that I never do. Having said that, on a few occasions (on wet tar) I braked a little harder than normal when the robots changed and I decided to do the right thing and stop! This is when I had the loud noise, and, more importantly the fact that the car did'nt stop - it felt almost like the wheels locked and I was sliding. Tyres are new Cooper ST MAXX's. I have also heard this noise on about four other occasions over the past five years in dry weather and on different surfaces, but never associated with hard braking.
Graham did pick up that the car has been braking only on the front which probably explains the bad stopping distances in the wet.
My concern is that ABS surely only kicks in with hard braking - or am I mistaken and it's there at all times, especially with wheels on uneven surfaces.
Regards
Tony

It sounds like its working normally except for the "braking only on the front wheels" thing. As far as I know, it should not normally operate other than under hard braking. Are you sure your vehicle does not maybe have stability assist or something like that and maybe that is what is operating to keep the machine stable on an uneven surface? That said, it occurs to me that with normal braking on a very uneven surface perhaps a wheel might momentarily experience reduced traction and stop turning, causing a very sensitive ABS to operate. What is the condition of your shock absorbers?

[Clem]

PS: I also suspect the live axles would be more likely to "skip" one very uneven surfaces than independent suspension. Perhaps someone else will comment on this.

[Stefan]

It sounds like the ABS to me.

Maybe I should have qualified "very hard braking". As far as I understand ABS it will sense when the wheels start to lock up and then engages. Mine makes a sort of 'Grrrrr' sound when it does.