E brake after brake change

[Pondy]

Hello again,

So I thought I would change the discs and pads on my car because a). I haven't got much else to do at present and b) I could save a few quid and C) I'm a sadist!

I asked questions on here before I committed to doing it and had a look at some YT videos. The YT videos I found were useless (apart from one really good tip for getting the discs off the hub).

The only way I could get the rear piston to retract enough to get the caliper back on the new (thicker) disc with the much meatier pads was to remove the Ebrake motor and wind the spline all the way out, then compress the piston with a clamp (it was really stiff).
So, I got the calliper back on, stuck the handbrake motor back on, did everything back up. There was a bit of play in the caliper as the piston was pushed fully back. This was sorted by pumping the brake pedal, happy days.

I haven't tried the handbrake yet.

My concern is; as I manually wound the Ebrake actuator back to compress the piston but the motor is in the same position as it was when I removed it, should the Ebrake compensate? IE does it (they) have some kind of pressure sensor to stop the motor when the piston is gripping the disc?
I'm worried about activating the Ebrake until I am confident it will be OK.

BTW I saw a post on here where someone reckoned 35-40 minutes per corner for disc and pad change. I spent 7 hours on it yesterday and have done one front and one rear so far!!

 

[Chippie]

Now you know what you are doing you’ll have the other side done in half the time
I’m pretty sure you just apply the handbrake a few times and it works out how long the apply the motor

 

[tintoverano]

I did two videos putting the ebrake into workshop mode and back using software

[youtube]QgctXhBjxtU[/youtube]

if you're interested in setting up a laptop, pm me

 

[Zed Baron]

Don't know if this would help, I bought one of these to register my battery (which it did), but Im sure it does the EPB stuff as well: '【Special functions for BMW】Engine, ABS, airbag, transmission systems scanning and live data stream is available. Reset Service interval indicator, CBS Reset, ECT Reset, PCM Clear Adaptations, battery management reset, electronic parking brake. ' Might be worth investigating for £71:
https://www.amazon.co.uk/AUTOPHIX-Multi-System-Diagnostic-Transmission-Registration/dp/B08DG22XHF/ref=sr_1_1_sspa?adgrpid=110197680956&dchild=1&gclid=Cj0KCQiAvbiBBhD-ARIsAGM48byoSHCZforAEBAt9tMWr_1p8oOfqbq79fV9S4e9d02qCkC8NIwydCkaAgtTEALw_wcB&hvadid=468989439756&hvdev=c&hvlocphy=1007341&hvnetw=g&hvqmt=b&hvrand=9787194563352249093&hvtargid=kwd-967170218159&hydadcr=1097_1866886&keywords=autophix+5900&qid=1613665315&sr=8-1-spons&tag=googhydr-21&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyWjJJSUtQRlZCOVREJmVuY3J5cHRlZElkPUEwMTg2OTI4VzJYTVo3RVRXU09QJmVuY3J5cHRlZEFkSWQ9QTA5NDU1MjgxQlJRM0ZMNVBBREkyJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

 

[Pondy]

Thanks but I don't have a diagnostic tool or any OBD stuff. I can just about do nuts and bolts, I don't do computers.

I have now done the other two discs so I shall see what happens!!

If it doesn't want to play I will get my (BMW specialist) mechanic to sort it when I take the car for a service next week.

 

[Smartbear]

The e89 senses if the car moves with the handbrake applied & applies more force to the ebrake to halt the car
Rob

 

[Pondy]

Now you know what you are doing you’ll have the other side done in half the time
I’m pretty sure you just apply the handbrake a few times and it works out how long the apply the motor

Yes it only took me three hours to do the other two!

It would appear that the Ebrake sorted itself out. I took the car up the road just to check the brakes actually work; they do!

I applied the Ebrake (with fingers crossed), it took a while for the motors to apply force (I'm presuming this is because I had wound the actuators right out). I did it again and it seemed like normal. No warnings on the dash and the brake is applied. So it would seem that it is all OK.

Maybe because I released the electric brake before staring the work (and left it off) and it doesn't self-apply, it didn't know any different? I have no clue.

Cars are just too damn complicated these days! :x

 

[flybobbie]

If you have taken the plug off the ebrake motor, you might get on a reader a ebrake motor fault code, but just delete it.
There is a bedding procedure, but i never used it or had problem.

 

[Jollyjoiner]

Don't forget if you also want to reset the brakes service interval on the dash then you have to do with the handbrake in the off position

 

[Pondy]

Don't forget if you also want to reset the brakes service interval on the dash then you have to do with the handbrake in the off position

The stealer who I bought the car from has reset everything (without replacing anything obviously)! The rear pads were almost shot but the computer said 25,000 miles to change!

Rear discs and pads from factory, not sure about fronts.

I changed the air filter too today. It was the original! Date mark of Dec 2012. Car manufactured March 2013, has 25k on it but it was a bit grubby!

If nothing else, I am confident the mileage is genuine

 

[Nictrix]

Don't forget if you also want to reset the brakes service interval on the dash then you have to do with the handbrake in the off position

The stealer who I bought the car from has reset everything (without replacing anything obviously)! The rear pads were almost shot but the computer said 25,000 miles to change!

Rear discs and pads from factory, not sure about fronts.

I changed the air filter too today. It was the original! Date mark of Dec 2012. Car manufactured March 2013, has 25k on it but it was a bit grubby!

If nothing else, I am confident the mileage is genuine

After a reset it should read more than 25,000 miles for the rears I think

 

[Pondy]

Don't forget if you also want to reset the brakes service interval on the dash then you have to do with the handbrake in the off position

The stealer who I bought the car from has reset everything (without replacing anything obviously)! The rear pads were almost shot but the computer said 25,000 miles to change!

Rear discs and pads from factory, not sure about fronts.

I changed the air filter too today. It was the original! Date mark of Dec 2012. Car manufactured March 2013, has 25k on it but it was a bit grubby!

If nothing else, I am confident the mileage is genuine

After a reset it should read more than 25,000 miles for the rears I think

Just checked: 40k rears 25k front!

 

[mcbutler]

7 HOURS!!!!!

I did mine, all went well. I also wound the pistons back on the rears after removing the handbrake motors, you should use an allen key, the piston rod has an allen socket end for this purpose.
Having taken advice froma pro beforehand I was advised that once the pistons were fully back to wind them back just a touch so that the rod was not locked by friction in the fully open state.
Pads - discs fitted, jumped in, pumped pedal, checked fluid level, pulled handbrake lever all well no lights or anything....

 

[Pondy]

I did mine, all went well. I also wound the pistons back on the rears after removing the handbrake motors, you should use an allen key, the piston rod has an allen socket end for this purpose.
Having taken advice froma pro beforehand I was advised that once the pistons were fully back to wind them back just a touch so that the rod was not locked by friction in the fully open state.
Pads - discs fitted, jumped in, pumped pedal, checked fluid level, pulled handbrake lever all well no lights or anything....

Yes it turns out it is that simple! There seems to be a culture of "plug it into a computer and do everything electronically" when in circumstances like this is it not necessary. Maybe it's a generation thing.

 

[Pondy]

The e89 senses if the car moves with the handbrake applied & applies more force to the ebrake to halt the car
Rob

I'm interested; how does it "sense"? The only other electrics are ABS sensors (I think) on the brakes. Does it use these?

I noticed if you try to move the car with the ebrake applied, it shouts a message on the dashboard to say the parking brake is on

 

[Chippie]

The e89 senses if the car moves with the handbrake applied & applies more force to the ebrake to halt the car
Rob

I'm interested; how does it "sense"? The only other electrics are ABS sensors (I think) on the brakes. Does it use these?

I noticed if you try to move the car with the ebrake applied, it shouts a message on the dashboard to say the parking brake is on

I would hazard a guess that the ECU monitors the current draw when the EPB is applied and knows when it can’t turn anymore

 

[flybobbie]

The ebrake and the way it works is probably the best system i have seen on a car. No more slack handbrake cables to adjust every time the car approaches the MOT. And simple to work on.

I had a RX7, the most stupid handbrake design, had a rod going into the back of the caliper to press on the piston, that always leaked brake fluid.

 

[Pondy]

I would hazard a guess that the ECU monitors the current draw when the EPB is applied and knows when it can’t turn anymore

Yes it must regulate by a current switch, but I can't see how it can apply more if the car moves. The only way it can apply more force is by the motor turning the actuator more. If it has decided, by means of a current switch, that enough pressure is exerted, how can it apply more?

 

[warmasice]

I did two videos putting the ebrake into workshop mode and back using software

[youtube]QgctXhBjxtU[/youtube]

if you're interested in setting up a laptop, pm me

Good to know. Thanks

 

[Smartbear]

I would hazard a guess that the ECU monitors the current draw when the EPB is applied and knows when it can’t turn anymore

Yes it must regulate by a current switch, but I can't see how it can apply more if the car moves. The only way it can apply more force is by the motor turning the actuator more. If it has decided, by means of a current switch, that enough pressure is exerted, how can it apply more?

Here you go, it’s all clever stuff

Rob