URGENT help needed, suspected braking issue, extremely confused

[gareth82]

Hi all, seeking some advice as this one has me stomped  :'(.  My 2001 X5 3.0d has left me stranded and confused  :-[.  I changed the front brake discs and pads about 5 weeks, with no issues and have done 700 mile since, 2 weeks ago I had a front passenger wheel bearing changed and have done around 300 mile since, (abs wheel sensor and check brake lining fault occasionally pops up on the side that had wheel bearing changed).

Today I drove 20 mile, parked up for an hour, then drove a further 20 mile with no issues at all.  Parked up for 5 minutes then when to drive off and it was as if my brakes where randomly sticking on fully.  My X5 is not driveable now.

If I move off without pressing the accelerator pedal it slowly strolls on, if I press the fast pedal the car appears to apply the front drivers side brake heavily and stops the car driving instantly, you can feel the brake pedal kicking as if the abs has kicked in.  If I stroll along is not to bad, 2-3mph more and brakes are fully applied without touching the pedal.

The only brake disc that is noticeably hotter than the others is the drivers front.  This points me in the direction of a faulty calliper although this is the confusing part, when I move without pressing the pedal it rarely does it, and when the accelerator pedal is touched slightly and speed builds up towards 5mph the car violently tries to stop (feels like the drivers front calliper only), although when going slowly its ok and gets violently worse with hardly touching the gas pedal.  The wheel can be turned freely by hand.

I have had a seized calliper before and it was not these symptoms at all.

Any ideas guys?

Thanks and greatly appreciated

[X5Sport]

Are the pads/calipers sliders all fitted correctly?  The caliper is a floating type and should move freely.  The pads should be able to move too.  Also need to check the sensor cables are all intact/properly routed and correctly plugged in. 

If you lift the wheel off the ground does it rotate freely?  If held at 12/6 o'clock positions, does it rock very much?  It shouldn't if the bearing is correctly seated and pre-loaded.

When the pads were replaced, did they put a new sensor in too?  Can't remember which side the front one is located.

It sounds like something is 'grabbing' and that then triggers the ABS.

[gareth82]

Thanks for the reply, The senor is fitted in the passenger side and does occasionally flag the check brake linings fault which I doubt is related. (this has been happening since passenger wheel bearing changed)

I have lifted both front wheels off the ground and there is no obviously wheel bearing play and both rotate freely which has me puzzled.

I agree it does sound like something is grabbing and that triggers the ABS although  don't understand why only the front drivers brake disc heats up and why at rolling speeds its ok.

Don't want to pay £70+ for transportation to a mechanic if its something simple.

Thanks and appreciated

[X5Sport]

That caliper obviously needs a closer look to make sure everything is properly done up.  It could even be loose!

[gareth82]

[quote="X5Sport"]
That caliper obviously needs a closer look to make sure everything is properly done up.  It could even be loose!
[/quote]

Its not loose, although your right I will pull apart tomorrow and inspect.  It has me puzzled as below 5 mph its not too bad, above 5mph its violent, its as if brake fluid is being pushed down to the front side of the car only which isn't possible so I guess it has to be the calliper at fault, just never seen a calliper fail with these odd symptoms.

Thanks

[kkx5]

Press and hold dsc button to disengage the system, drive it...Let us know

[Steamyrotter]

I would look at the and sensor plug in the wheel well

These get crudded up and can cause false triggers.

If nothing else at least it is quick easy and cheap to check.

[X5-D-Sport]

I had similar issues last yearafter fitting new pads...

Calliper was siezing casing the ABS to boit in an wheel wobble feedback thru the steering....

If one disk only is getting hot, it sounds similar to my problem..

A new front caliper seal & piston kit solved the problem...  £25 Ebay..

[LooneyLeon]

Sounds scary, please let us know how u get on?

[gareth82]

Hi all, thanks for the replies,  I spent today working on it, firstly I removed the calliper, all was fitted correctly, I re-greased the sliding pins and refitted, same problem.

I then disconnected the abs sensor and cleaned connection and reconnected, same problem.

I rescanned with INPA and no DTC's stored pointing to the wheel of concern. I tried turning off the DSC this also made no difference, I then held the DSC button for 20 seconds and tried again, no difference

I then disconnected the drivers front abs sensor and voila the car would let me drive, done 15 mile this afternoon to see and it drove fine other then the cluster lit like a Christmas tree lol.

I guess its not the module or wiring as no DTC was present meaning the ABS sensor has when faulty but in a way not storing DTC's.  Scary how this can happen and fully take down the car with no warning at all

Is there anything worth checking before ordering a new sensor?

Thanks

[X5Sport]

Glad you are getting to the bottom of it.  Sensor error recording is only as good as the systems monitoring them recognising a fault condition.