Rear brakes

[jojackson4]

Gents I have a strange pulsating brake on the rear of my 2005 330d

It feels like the TC or ABS is controlling the calliper when driving without any brake input

I have pulled the abs sensor connector to see if that stopped it but no dice

Anyone had this or know what could be the cause

Peter

[RicoOS]

Sounds most likely to be potentially a warped disc on the rear, if the pedal pulse's, either that or potentially an ABS fault. Have a look at the rear discs and see if they are worn, likely to need replacing soon anyway and if so, replace them and the rear pads and see if this solves the problem.

[d_a_n1979]

jojackson4 said:

Gents I have a strange pulsating brake on the rear of my 2005 330d

It feels like the TC or ABS is controlling the calliper when driving without any brake input

I have pulled the abs sensor connector to see if that stopped it but no dice

Anyone had this or know what could be the cause

Peter

Could be a a sticking caliper or brake pad deposits built up etc...

If you go out in the car; try some hard braking (making sure its safe to do so) and then drive home normally. See if a) that clears any built up deposits and b) see if the caliper & alloy are hot to the touch; if they are, you've a caliper sticking and it needs to be swapped out.

I'm a firm believer that unless the disc was crap from factory; road going cars aren't really able to 'warp' discs due to the masses of heat needed to do this; track day cars, yes, as they're on the brakes, hard, regularly!

All in; get the brakes properly checked over and see what's going on. ATE, Jurid and Textar are OEM brands FYI if you go non-OEM BMW

[jojackson4]

Not a warped disc
Had the wheel off and there is apox 20 marks around the disc where it’s been braking it’s self
Looks like it’s apliying the brake on the one wheel at the exact same time on every rotation

It’s doing it with no brake input from the driver but only after a mile or 2

[d_a_n1979]

jojackson4 said:

Not a warped disc
Had the wheel off and there is apox 20 marks around the disc where it’s been braking it’s self
Looks like it’s apliying the brake on the one wheel at the exact same time on every rotation

It’s doing it with no brake input from the driver but only after a mile or 2

Sounds like an ABS issue.

You need to get it plugged into INSTA/INPA/bimmercode or similar and see what codes are stored in the cache etc

No point in guessing what's going on until you've done that

[jojackson4]

Just strange the dash hasn’t lit up like a Christmas tree

[E-bmw]

jojackson4 said:

Gents I have a strange pulsating brake on the rear of my 2005 330d
Peter

What is telling you that the brake is "pulsating"?

How do you feel/see/hear that it is "pulsating"?

jojackson4 said:

Had the wheel off and there is apox 20 marks around the disc where it’s been braking it’s self
Looks like it’s apliying the brake on the one wheel at the exact same time on every rotation

We need to see a pic of that to help.

[d_a_n1979]

jojackson4 said:

Just strange the dash hasn’t lit up like a Christmas tree

Doesn't always happen.

As said, it could still be a mechanical issues rather than ABS that's why it needs plugging in

[Pica-Pica]

d_a_n1979 said:

jojackson4 said:

Just strange the dash hasn’t lit up like a Christmas tree

Doesn't always happen.

As said, it could still be a mechanical issues rather than ABS that's why it needs plugging in

It could be a seal/valve that is holding brake pressure on. Just high enough, but not too high, so as to press and release the pad on to and off the disc. I would look at the calipers first, remove, clean, grease sliders (if recommended/appropriate)

[fatboy b]

Have you replaced any tyres? The e46 doesn’t handle replacing one end very well.

[stevesingo]

jojackson4 said:

Not a warped disc
Had the wheel off and there is apox 20 marks around the disc where it’s been braking it’s self
Looks like it’s apliying the brake on the one wheel at the exact same time on every rotation

It’s doing it with no brake input from the driver but only after a mile or 2

What are the chances of the ABS system choosing to apply the brakes in the exact same place on the disc every single time?

IMO, zero.

What is more likely is that you have a sticky caliper and you have, in the past, braked hard to a stop and left your foot on the brake. Hot pad on hot disc = pad transfer (high friction pad material adhered to disc face). Now every time your pad, held by the sticky caliper, passes over the region of the disc with pad transfer, the pad grabs. Every time it grabs it generates friction and heat. every time it passes you get more heat and more transfer.

Change the discs and pads, and ensure the caliper piston if not binding up and the slide pins are clean and correctly lubricated.

[E-bmw]

stevesingo said:

jojackson4 said:

Not a warped disc
Had the wheel off and there is apox 20 marks around the disc where it’s been braking it’s self
Looks like it’s apliying the brake on the one wheel at the exact same time on every rotation

It’s doing it with no brake input from the driver but only after a mile or 2

What are the chances of the ABS system choosing to apply the brakes in the exact same place on the disc every single time?

IMO, zero.

What is more likely is that you have a sticky caliper and you have, in the past, braked hard to a stop and left your foot on the brake. Hot pad on hot disc = pad transfer (high friction pad material adhered to disc face). Now every time your pad, held by the sticky caliper, passes over the region of the disc with pad transfer, the pad grabs. Every time it grabs it generates friction and heat. every time it passes you get more heat and more transfer.

Change the discs and pads, and ensure the caliper piston if not binding up and the slide pins are clean and correctly lubricated.

Hence my questions above, when we have the full story we stand a chance of being helpful.

[jojackson4]

The feeling of the brake being applied is that the rear end starts to feel like it’s squatting/or shaking like a dog wagging it’s tail
You fell nothing in the peddle
Turning TC off makes no difference
Wheel turns free when jacked up
No binding at any point

The problem only starts after driving for a mile or so and after applying the brakes 10-15 times

It’s had a pair of tyres on the front a month ago but that’s nothing new it’s always had them in pairs for 15 years

Hopefully I will get it to someone who can plug in this afternoon


Thanks for your replies gents

[fatboy b]

jojackson4 said:

The feeling of the brake being applied is that the rear end starts to feel like it’s squatting/or shaking like a dog wagging it’s tail
You fell nothing in the peddle
Turning TC off makes no difference
Wheel turns free when jacked up
No binding at any point

The problem only starts after driving for a mile or so and after applying the brakes 10-15 times

It’s had a pair of tyres on the front a month ago but that’s nothing new it’s always had them in pairs for 15 years

Hopefully I will get it to someone who can plug in this afternoon


Thanks for your replies gents

My 330Ci used to apply the rear brakes on slight bends after a new set of front tyres. It can't recalibrate itself I was told by BMW - only fixed by getting a new set of rears.

[E-bmw]

jojackson4 said:

The feeling of the brake being applied is that the rear end starts to feel like it’s squatting/or shaking like a dog wagging it’s tail
You fell nothing in the peddle
Turning TC off makes no difference
Wheel turns free when jacked up
No binding at any point

"Squatting/shaking/wagging tail" is such a wide/wooly description that it could still be many things.

100% it is not TC/ABS related.

I doubt it is actually brakes.

Sounds more like either wheel/tyre or suspension related.

Swap wheels front to rear & see what happens then.

[jojackson4]

The heat in the wheel and disc says it’s brakes

[d_a_n1979]

jojackson4 said:

The heat in the wheel and disc says it’s brakes

Exactly what I said...

[E-bmw]

d_a_n1979 said:

jojackson4 said:

The heat in the wheel and disc says it’s brakes

Exactly what I said...

What heat in the disc, I haven't seen that mentioned by the OP.

[jojackson4]

Just got back from the diagnostic machine

Abs pump nothing amiss no silly readings
No faults apart from a cam position sensor
So the only thing to do I think is to strip it down and make sure calliper and flexi is ok (as one of you have suggested)
It’s the strangest brake fault I have witnessed
Tomorrow is dirty day

[d_a_n1979]

E-bmw said:

What heat in the disc, I haven't seen that mentioned by the OP.

I said after braking to see if the wheel and caliper are hot to the touch; hotter than they should be. All signs of a sticking caliper