Update - I tried everything I could find to solve this problem - it seemed to be getting worse. Until one day slowing on the motorway the brakes locked on - mayhem ensued.
I concluded that it could only be the brake controller – even though it had no faults indicated
I couldn’t find details on how to change the brake controller so thought I would compose a short “how to” on replacing the brake controller and Master Cylinder.
I have read reports on dealers charging £2500 for the controller and £1500 labour.
In summary, I bought the controller for £80, bleed nipples for £7 and it took me 2 hrs to fit it. Make sure you get the correct controller. As far as I can see there are a min of 3 different types, 2 pressure sensors (up to about 2015) 1 sensor for 2016 and 17 models and none after that. The main connector after 2015 seems to have only 2 row of pins.
You will need –
- a method of bleeding the ABS pump, I used autocom
- a deep 13mm socket and swivel piece
- some metric spanners and general sockets
- Possibly a small wiper arm remover – I didn’t need this
- Mole grips for the bleed nipples
Disconnect the 12V battery
Remove the windscreen wipers
Remove the scuttle panel – 2 plastic rivets and few U clamps, then slide it forwards.
Remove the 2 bolts holding the wiper motor in place and move the motor out the way.
Remove the lower scuttle panel – usually black. 8 off 6mm bolts (10mm heads) and remove the panel. This gives you much better view on the brake controller.
Unplug the big power and data connector
If you have a pressure sensor (under the Master Cylinder), or even 2, unplug them.
Now inside the car, remove the little panel that’s above the pedals – 2 plastic rivets.
Remove the circlip that goes through the brake arm and pop out the connecting pin – it’s got little plastic clips on the end; you can try pressing then down– I just used a bit of force and all was OK.
Now, on the brake pedal remove the 4 nuts that hold the brake controller in place. You need a deep 13mm and a swivel piece.
Back under the bonnet, remove the 2 brake pipes that go in the master cylinder. Don’t get them muddled up.
Pop off the main cable support
Out is comes.
Putting it back together is just the reverse
All this took me about 1hr 15 mins
When I powered the car up and cleared any errors (all depends on what’s the history of the car you got the donor unit from) everything worked just fine – I just didn’t have any brakes
Now to bleed the brakes – what a pain in the butt. Suspecting I would be bleeding each wheel multiple times I put the car on axle stands
All the bleed nipples were badly corroded – just take your time, release oil and small movements worked for me. I replaced all the nipples for St Steel ones. Front are M10 x 1.0 and the rears are M7 x 1.0
I just worked round each wheel, activating the ABS pump and opening the solenoid then bleeding the air out
All in all, it took me about 2 hrs start to finish
Now by the looks of it, it might possible be possible to sperate the master cylinder and controller in the car, leaving the master cylinder in place – this would eliminate the brake bleeding fiasco.
Just bear in mind, if you go down this route as soon as you take the 2 Master Cylinder bolts out there are 2 big and small spring that will push it off, getting that back together in the car might be a challenge.
Or you could try firstly gravity bleeding first the master cylinder and then the pipes going to the ABS pump.
Been fitted now for 8 days and so far so good
