spannering your worst mistakes
spannering your worst mistakes
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Purosangue

Original Poster:

1,736 posts

34 months

Friday 12th December 2025
quotequote all
owned lots of classics so very used to changing brake parts , bleeding brakes etc.

So on the trusty Mitsubishi outlander PHEV mk3 2016 , at 126,000 miles thought time to replace the pads and discs , had noticed the rears where binding , so with new Bilstein calipers at £ 60 each , Bilstein discs at £25 and pads £26 . bought a set from Germany . , plus 2 litres of dot4 brake fluid . ( manual hand brake not electric)

removed each side and manually bled the brakes with son in passenger seat , had a nice flow of oil with no bubbles at the calipers , topping up resevoir as required. .

Then started engine brake straight to the floor , checked resovoir , low so topped up . tried again same thing vacumm pump engaging . brake marginally better , left overnight. cold morning started car , once heated up heard vacumm pump brake service required light illuminated checked resevouir .... almost empty !! . Topped up , so by now nearly 2 lites of brake fluid used. pedal still not right .. Called AA as we had home service , chap said fairly sure to bleed the brakes it has to be done with car plugged in .OBD

He was right we plugged in and followed the procedure .........all good ....err no on completion had good brakes drove around the block all good .
AA left . The following morning drove a mile to the local Screwfix on the journey , the brake service required light illuminated again but this time the brake pedal went to floor ......with no brakes .. luckily no other traffic around so Hazard lights on . and used the regenetrive braking mode on the car to slow down using the engine to slowly getting the cas back home using hand brake . parked up and booked in to local dealership for service

guessing that the brake master cylinder seals have failed with the brake fluid being sucked into the brake booster and vacumn ... will wait to see thge outcome

Edited by Purosangue on Friday 12th December 16:38

droopsnoot

14,028 posts

263 months

Friday 12th December 2025
quotequote all

E-bmw

12,001 posts

173 months

Saturday 13th December 2025
quotequote all
Purosangue said:
owned lots of classics so very used to changing brake parts , bleeding brakes etc.

So on the trusty Mitsubishi outlander PHEV mk3 2016 , at 126,000 miles thought time to replace the pads and discs , had noticed the rears where binding , so with new Bilstein calipers at £ 60 each , Bilstein discs at £25 and pads £26 . bought a set from Germany . , plus 2 litres of dot4 brake fluid . ( manual hand brake not electric)

removed each side and manually bled the brakes with son in passenger seat , had a nice flow of oil with no bubbles at the calipers , topping up resevoir as required. .

Then started engine brake straight to the floor , checked resovoir , low so topped up . tried again same thing vacumm pump engaging . brake marginally better , left overnight. cold morning started car , once heated up heard vacumm pump brake service required light illuminated checked resevouir .... almost empty !! . Topped up , so by now nearly 2 lites of brake fluid used. pedal still not right .. Called AA as we had home service , chap said fairly sure to bleed the brakes it has to be done with car plugged in .OBD

He was right we plugged in and followed the procedure .........all good ....err no on completion had good brakes drove around the block all good .
AA left . The following morning drove a mile to the local Screwfix on the journey , the brake service required light illuminated again but this time the brake pedal went to floor ......with no brakes .. luckily no other traffic around so Hazard lights on . and used the regenetrive braking mode on the car to slow down using the engine to slowly getting the cas back home using hand brake . parked up and booked in to local dealership for service

guessing that the brake master cylinder seals have failed with the brake fluid being sucked into the brake booster and vacumn ... will wait to see thge outcome
If you have used that much fluid it must be leaving the closed system somewhere, that being the case it should be pretty easy to find where it is going.

Check every fitting you worked on for evidence of fluid in the first instance.

Purosangue

Original Poster:

1,736 posts

34 months

Saturday 13th December 2025
quotequote all
E-bmw said:
Purosangue said:
owned lots of classics so very used to changing brake parts , bleeding brakes etc.

So on the trusty Mitsubishi outlander PHEV mk3 2016 , at 126,000 miles thought time to replace the pads and discs , had noticed the rears where binding , so with new Bilstein calipers at £ 60 each , Bilstein discs at £25 and pads £26 . bought a set from Germany . , plus 2 litres of dot4 brake fluid . ( manual hand brake not electric)

removed each side and manually bled the brakes with son in passenger seat , had a nice flow of oil with no bubbles at the calipers , topping up resevoir as required. .

Then started engine brake straight to the floor , checked resovoir , low so topped up . tried again same thing vacumm pump engaging . brake marginally better , left overnight. cold morning started car , once heated up heard vacumm pump brake service required light illuminated checked resevouir .... almost empty !! . Topped up , so by now nearly 2 lites of brake fluid used. pedal still not right .. Called AA as we had home service , chap said fairly sure to bleed the brakes it has to be done with car plugged in .OBD

He was right we plugged in and followed the procedure .........all good ....err no on completion had good brakes drove around the block all good .
AA left . The following morning drove a mile to the local Screwfix on the journey , the brake service required light illuminated again but this time the brake pedal went to floor ......with no brakes .. luckily no other traffic around so Hazard lights on . and used the regenetrive braking mode on the car to slow down using the engine to slowly getting the cas back home using hand brake . parked up and booked in to local dealership for service

guessing that the brake master cylinder seals have failed with the brake fluid being sucked into the brake booster and vacumn ... will wait to see thge outcome
If you have used that much fluid it must be leaving the closed system somewhere, that being the case it should be pretty easy to find where it is going.

Check every fitting you worked on for evidence of fluid in the first instance.
done that not a drop , no visible leaks followed the lines from each caliper to the master cylinder so it has to be internal tried to pull off the vacumn hose from the booster but its difficult to get to . I suspect it will be full of Brake fluid , which will mean a replacement master cylinder and booster unit

Griffith4ever

6,206 posts

56 months

Saturday 13th December 2025
quotequote all
Doing the rear discs and pads on my R8 V10. Jacked up, wheel off, parking brake released (can't get the disc off otherwise), in gear (4x4). Started raining, went in and left it.

Next morning, resumed the (easy) job. Before I attacked the disc I went to put an axle stand underneath, jacked it up just a little more with my low profile trolley jack to give room for the axle stand. Front wheel left the ground - handbrake is OFF - car rolled backwards.

Axle stand through the rear bodywork and trolley jack sideways, crushed, with the side handle burried in the floor pan. £900 repair and repaint later, all done (though there is still the dent in the floor pan). Amazing professional repair.

I have joked that the whole job was STILL cheaper than using a garage and OEM discs, including all parts, plus the damage!


Purosangue

Original Poster:

1,736 posts

34 months

Saturday 13th December 2025
quotequote all
Griffith4ever said:
Doing the rear discs and pads on my R8 V10. Jacked up, wheel off, parking brake released (can't get the disc off otherwise), in gear (4x4). Started raining, went in and left it.

Next morning, resumed the (easy) job. Before I attacked the disc I went to put an axle stand underneath, jacked it up just a little more with my low profile trolley jack to give room for the axle stand. Front wheel left the ground - handbrake is OFF - car rolled backwards.

Axle stand through the rear bodywork and trolley jack sideways, crushed, with the side handle burried in the floor pan. £900 repair and repaint later, all done (though there is still the dent in the floor pan). Amazing professional repair.

I have joked that the whole job was STILL cheaper than using a garage and OEM discs, including all parts, plus the damage!

christ i feel your pain ,

i never like having to take off rear callipers with the car jacked up and hand brake released

glad you got it sorted

fooman

1,016 posts

85 months

Sunday 14th December 2025
quotequote all
I filled an engine with gear box oil, it ran pretty good though. Changed it pretty quickly after, didn't cause any long term issues.

Griffith4ever

6,206 posts

56 months

Monday 15th December 2025
quotequote all
Purosangue said:
christ i feel your pain ,

i never like having to take off rear callipers with the car jacked up and hand brake released

glad you got it sorted
I was amazed at what I actually got away with. The jack rolling on its side stopped the disc & car from grounding out, along with the axle stand in teh bumper!! The jack side handle was VERY close to trashing the cill. Missed it by a few mm.

Repair was in for a week, entire rear off, plastic patched, braced, painted - you'd never know. Took the opportunity to replace the old knackered under-pan air scoops at the same time

Ian Geary

5,337 posts

213 months

Tuesday 30th December 2025
quotequote all
E-bmw said:
If you have used that much fluid it must be leaving the closed system somewhere, that being the case it should be pretty easy to find where it is going.

Check every fitting you worked on for evidence of fluid in the first instance.
I have put some stories on the other diy disaster thread...

But this reminds me of using an old gunson ezebleed system with a spare trailer tyre.

Bottom line the tyre was flat and I somehow syphoned a shed load of brake fluid into the tyre!

I was beginning to wonder where it was going.

Got myself a bleeding kit with a pump after that

(Ps don't undo the master cylinder connector without releasing the pressure first - a mistake you only make once...)