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E87 DSC HYDRO UNIT REPLACEMENT DIY

94K views 19 replies 11 participants last post by  Dominic H 
#1 ·
Hi All,

I thought I would share the DSC Hydro unit DIY that I done this morning.

As many of you know if your DSC unit fails you get some nasty errors on the dash and you may think this is very expensive!

However you can get a "rebuild" kit direct from BMW for £168 Inc VAT.

This takes about 2-3 hours.

Before you carry this out you will need to get hold of BMW's diagnostic software INPA or DIS as you need to bleed the system using activation of the DSC Pump.

You will also need a pressure bleeder, you can pick these up from halfords for about £20

1. Open the bonnet, boot and front doors.

2. Disconnect the negative battery terminal in the boot.

3. Jack up the passenger side of the vehicle and remove both front and rear passenger side wheels.

4. You will need to depress the brake pedal about half way for the removal and refit of the DSC unit, if you have something telescopic perfect if not a suitable size bit of 2x2 would work just as well forced against the drivers seat.

5. Release the pressure created from pressing the brake pedal by opening the bleed screws on the passenger side brake calipers. 9mm spanner should do it. (remember to use a brake bleeding bottle to catch fluid)



6. Remove the pollen filter, scuttle, and plastic covers from around the DSC area, very easy 8 x 8mm bolts.

7. Label the brake lines on the DSC unit so that you make sure they go back in the same place



8. Remove the brake lines from the DSC unit, be ready to catch a very small amount of brake fluid MAKE SURE NONE GETS ON YOUR PAINTWORK AS ITS CORROSIVE!!!! the kit is supplied with plasic plugs to plug the holes in the old DSC unit.

9. Remove the main wiring harness connector by pulling up on the grey locking mechanism to remove, cover with tape to protect the pins.

10. Remove the DSC unit from the vehicle, this will take a bit of fiddling





11. Separate the DSC pump from the ECU part of the DSC module by undoing 2 torx bolts on the body of the DSC pump, 1 long 1 short. (BE VERY CARFULL HERE, THERE ARE VERY SMALL PINS WHICH YOU DO NOT WANT TO DAMAGE, TAKE IT APART STRAIGHT AND SMOOTH)




12. slide on the new DSC pump and do up the 2 torx bolts, you should get new ones in the kit.



13. Install back on the car in reverse order of what you have just done, taking care that everything is done up correctly.

14. Once you are happy everything is connected correctly, connect the battery. at this point you will find that your error has probably gone of the dashboard as ours did.

15. attach the pressure bleeder and bleed the brakes using the procedure outlined in BMW INPA. (bleeding procedure is under Chassis/DSC) (DO NOT DRIVE THE CAR UNTIL THIS HAS BEEN DONE YOU WILL HAVE AIR IN THE SYSTEM)

16. Clear any fault codes using INPA

17. Once you are happy and the brake pedal is nice and firm take for a careful test drive to make sure everything is working as it should.

18. Enjoy!
 
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#5 ·
What a legend, thank you very much for this.

I have a 130i which has recently developed this fault but unfortunately the kit required by my car is £800 :?

Saying that, I will be sending the unit off to ECU Testing to repair and I assume I can use this guide to remove/replace my unit?

Cheers.

Edit - Only just realised this has been posted some time ago :lol2:
 
#6 ·
guess ill being doing this , 1 thing why need to follow the inpa brake bleeding procedure , always start from furthest point from master cylinder and work towards it
 
#7 ·
I'm sure this thread will help Alot if others that have the same issue

Looks like an old thread but, it's still good for newer members to see as it's probably difficult to search for
........................................
2008-135i jb4 +mods
( Team Rob...............)
 
#11 ·
Guys I have just done mine, new hydro unit in and connected everything, however the error lights on the dash are still there, should I bleed the system first to remove the lights? Or I need the car connected to computer in order to remove the lights? Thanks very much!
 
#12 ·
stone3t said:
Guys I have just done mine, new hydro unit in and connected everything, however the error lights on the dash are still there, should I bleed the system first to remove the lights? Or I need the car connected to computer in order to remove the lights? Thanks very much!
So I took my car to a local small garage, they used their diagnostic tool to remove the warning lights, tested the car, ensured that nothing came up again, then they bled the brakes, all sorted. The garaged charged me £40 for the warning lights removal and the brake bleeding (using the brake fluid I provided), not bad I guess.
 
#13 ·
My 2007 120d has flashed up with the DSC fault. I've had it confirmed as a fault (by our local BMW AD) with the DSC/ABS hydraulic pump. They have quoted £2764 to replace the pump!

I would like to repair the pump with the BMW kit, does anyone have the part number or reference for the DSC repair kit?

Thanks in advance for any help.

Cheers

Dominic
 
#14 ·
Looks like there are a few different part numbers out there;

Part number 34516797896

Part number 34516791521

Best bet would be to get in touch with either Cotswold BMW (forum sponsor), or your local BM dealer parts desk, give them your VIN and they can ensure you get the right kit. I cant find either of those part numbers on realoem, so I cant verify their application.
 
#15 ·
Nottsknots said:
Looks like there are a few different part numbers out there;

Part number 34516797896

Part number 34516791521

Best bet would be to get in touch with either Cotswold BMW (forum sponsor), or your local BM dealer parts desk, give them your VIN and they can ensure you get the right kit. I cant find either of those part numbers on realoem, so I cant verify their application.
Thanks for the advice. Would you know if the OE BMW part will need reprogramming?
 
#16 ·
Not sure what you mean by reprograming, but assuming you mean "will I need INPA to reset it", then yes; even if you bleed the brakes incorrectly when changing fluid, you can get air in the unit, and then it needs to be cycled using INPA to clear out the air. Replacing the main component of the unit will also introduce air and so need cycling.

Its not like the old days, when you could bleed the brakes with a milk bottle and a ping pong ball, or fix an engine with a couple of spanners and a screwdriver. Get air in there, and there is no way to get it out without using electronic wizardry Mr Potter would be proud of.

If you cant find someone local to help you out, then Wibbles (see the forum section for BR Diagnostics & Retrofits is your man; invest in a cable and he can run the software from somewhere far, far away (oop beyond t'North). Where abouts are you?
 
#17 ·
Nottsknots said:
Not sure what you mean by reprograming, but assuming you mean "will I need INPA to reset it", then yes; even if you bleed the brakes incorrectly when changing fluid, you can get air in the unit, and then it needs to be cycled using INPA to clear out the air. Replacing the main component of the unit will also introduce air and so need cycling.

Its not like the old days, when you could bleed the brakes with a milk bottle and a ping pong ball, or fix an engine with a couple of spanners and a screwdriver. Get air in there, and there is no way to get it out without using electronic wizardry Mr Potter would be proud of.

If you cant find someone local to help you out, then Wibbles (see the forum section for BR Diagnostics & Retrofits is your man; invest in a cable and he can run the software from somewhere far, far away (oop beyond t'North). Where abouts are you?
Thanks for the advice. I'm in Bromley, north Kent.
 
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