Discovery 2 ABS binding drive system after hub rebuild

Hi, here I am again.

After a wheel bearing, CV joint brake rebuild, I drive it out of the garage and the TC cuts in and binds up the side of the drive that I have been working on. I am completely baffled. The bearing was from Craddock so I am assuming it is a proper 60 tooth ABS model, but I will manually count the teeth tomorrow. I think there is a Hawkeye test I can do where I spin the wheel. Is there anything else I can do?

Many thanks for all your help so far, sorry to be such a returning pain.

Cheers

Adam

Further to the above, I have just unplugged the ABS relay and driven the car round the block. Of course the 3 Amigos were lit but the car drove fine, but what does this mean regarding the TC/ABS system?

Thanks

a

It would appear to mean that the ABS system thinks the hub you were working on is spinning faster than it should be.
Is it at all possible that the new hub isn't the problem but the other side is?
Simple test, swop the two leads over as the ABS ECU or somewhere so it reads the nearside as the offside and vice versa. If it now locks the other side you will have narrowed down the problem.

Interesting theory StanleySteamer, the other hub is a different make but not so old. I will think that through and try it. Are the leads marked on the ABS ECU? The new nearside hub's sensor was duff when fitted, and I changed it from one from eBay.

adam koronka said:

Interesting theory StanleySteamer, the other hub is a different make but not so old. I will think that through and try it. Are the leads marked on the ABS ECU? The new nearside hub's sensor was duff when fitted, and I changed it from one from eBay.

Click to expand...

The thing that the new sensor was duff is not good. What was wrong with the one off your original hub?
When you first switch the car on and start it up, do the three amigos come on before you start to move, once you have reset them with your diagnostic, or do they only come on when you start to move? Cos the ABS ECU does a self test on the sensors to see if they are OK when static, apparently.
If they come on before you move off then the problem is more likely to be the sensor, if after you move off it is the interaction between the sensor and the hubs teeth, either the gap between the sensor and the inductor ring is wrong, or varying, or, as Sierra has pointed out many times, it could be to do with the number of teeth on the ring.
I am not well enough up on it to know if the swapping of the wires at the ABS ECU is that easy, if it was me I'd follow them from the hub. But I am sure someone on here will know, or it may well be in a RAVE wiring diagram. @sierrafery is the guy on here who knows shedloads more than i do. Hopefully he'll jump on.
Best of luck mate.

Thanks for getting back. When I fitted the new hub the fault lights couldn't be cleared by the Hawkeye so I initially replaced the sensor with the old one. The fault cleared but when I drove only a few yards I had the binding problem on the near side wheel. I stripped the whole corner down to check it was assembled correctly and it has been. When the wheel binds up I only get a TC warning light not the 3 amigos. The dreaded 3 only have come on when I removed the ABS relay.

Cheers A

Off course that when you remove the relay the TC can't kick in as the pump is disabled, there is a missbalance between the inputs from the wheels on that axle. The system is quite sensitive so it can kick in even if different brand hubs are fitted. The fact that you dont get the 3 amigos means that the sensors are passing the system self test so the problem occurs when the vehicle starts moving which means the input from the side which locks is higher than the other. Count the teeth of both hubs through the sensor hole to make sure they are the same and if they are swap the two sensors, if still no joy you'll have to buy a same brand hub and fit it to the other side. Once aftermarket hubs are involved these things happen, happened to me too and after a long joyless struggle i bit the bullet and replaced both hubs on the front with same brand ones(Borg and Beck) and that was the end of it

Many thanks for your help all the way through

cheers

Adam

Just an added thought, one of the replacement sensors came with a spacer. I didn't fit it as the original didn't have one. Would this alter the signal strength?

A

Yes it would cos that hub was tested as it came, reducing the air gap would alter the signal or even ruin the sensor also fitting other brand sensor would mix up the signal

Thanks - I will try that and report back

A

adam koronka said:

Thanks - I will try that and report back

A

Click to expand...

The sensor has to be correctly positioned in relation to the reluctor (is that the word? I forget) ring to .5mm.

A small update as I haven't yet had time to count the teeth of the wheel bearings etc, but the Hawkeye measured a voltage at the RHF sensor of 2.25 V and 2.27 on the LHF (the one the Traction control is binding with the brakes. So the theory is that the computer thinks the LHF wheel is spinning faster than the RHF (higher voltage) and so kicks in the brakes on that wheel. Therefore it looks like the spacer, once fitted, will increase the air gap, reduce the voltage slightly, even things up and bingo! Does that sound right?

Cheers

A

adam koronka said:

A small update as I haven't yet had time to count the teeth of the wheel bearings etc, but the Hawkeye measured a voltage at the RHF sensor of 2.25 V and 2.27 on the LHF (the one the Traction control is binding with the brakes. So the theory is that the computer thinks the LHF wheel is spinning faster than the RHF (higher voltage) and so kicks in the brakes on that wheel. Therefore it looks like the spacer, once fitted, will increase the air gap, reduce the voltage slightly, even things up and bingo! Does that sound right?

Cheers

A

Click to expand...

No, the acceptable difference for the system to work well is 0.3V so that 0.02v difference is 100% neglectable also the stationary sensor voltage test has nothing to do with the air gap whatsoever

Oh well, it was a nice theory while it lasted, thanks for your input again. Happy Christmas to you and all.


A

I am just feeding back after some time, just incase someone else finds themselves in the same situation. The problem arose when fitting the new hub. The sensor that came with it didn't connect - even with the Hawkeye, so I had no choice but to replace it, first with a new one...tested it, the traction control bound the brake, then with a known working one - which also bound the brake. I then laid the vehicle up over lock down. I replaced the new bearing with a new new one, in fact I fitted both sides with matching bearings just to make sure. The system connected up - even without the Hawkeye dialling them in - and now it is all working - at last! Thank you all for your help and input. The moral of the story? Follow the instructions and don't split the sensor from the hub ( although I had to as the sensor was duff)

Cheers

Adam