[Processing61]

I’ll try and make this as short as possible. E91 325D Msport 2008, U.K.

Rear left brake calliper started to stick on. It’s a high mileage car 197k and probably original callipers. Seemed like it was the piston and I was going to replace the whole calliper. I managed to get 3 used callipers (rl, fl, fr but no rr). I replaced the three callipers and on all four I replaced the slider pins and slider grommet thing. These callipers were supposedly in working condition and had been tested before selling, they did look in better condition than my old ones.

First mistake I made as I didn’t realise was that I didn’t depress the brake when any lines were open. I basically just capped it off with a tapered seal/plug and I didn’t lose much fluid at all.

When fitting callipers I noticed the brake hoses were not looking good so I thought I’d replace them while I was there. I replaced four, the only two I didn’t replace were the two rear nearer the middle, quite awkward to get to so decided to leave them and they actually looked in better condition compared to the others. I replaced with stainless steel braided hoses. In the process the rear left short hard line broke and was leaking, so I made a new line with kunifer pipe and double flare ends.

I then wanted to bleed the brakes and replace with new fluid so I got a pressure bleeder and removed the old fluid down to the min line in the reservoir. Then set bleeder to 10 psi to start to see if there were any leaks, no leaks and no pressure lost. Then added brake fluid to pressure bleeder and pumped to 15 psi, left for 10/15 mins, no leaks or pressure lost again. I then proceeeded to bleed all brakes from furthest to closest but each time the brakes were still very spongy, I did this about 5/6 times and the difference seemed negligible. There was air coming out of the callipers when looking at bleeder pipe at first but no more.

So I then saw you could do a brake bleed through ista which I did. It didn’t seem like the full process though. It basically got me to go RR, RL, FR, FL. each corner I would undo nipple then get in car, press brake down, hit continue then you’d hear some kind of pump (abs,DSC?) that would make some noise and put pressure on the pedal against you, close nipple and then it was done onto the next side.. It only did that cycle once on all the corners. So I did it 2/3 times more. Still no difference really when the engine was on and pressing the brake.

I then used the pressure bleeder 2/3 more cycles of bleeding, a few bubbles on the 1st and 2nd. Nothing at all on the 3rd. Still very spongy and when you put your foot down it would eventually go down to the floor.

I notice when I go round the callipers now with the car in neutral and handbrake off one or two of the wheels can spin with some resistance, and the other two, one can be just moved and the other is almost solid on.

So I’m just trying to figure out what to do next? Is there a better procedure to bleed on ista/inpa? Did I do anything really wrong? Could it be the callipers, new hoses or the line I made? Although there are no visual leaks and pressure tested fine?

Ok well this wasn’t short and sweet.

Anyway, any help is appreciated?

[eljay]

Originally Posted by Processing61

I’ll try and make this as short as possible. E91 325D Msport 2008, U.K.

Rear left brake calliper started to stick on. It’s a high mileage car 197k and probably original callipers. Seemed like it was the piston and I was going to replace the whole calliper. I managed to get 3 used callipers (rl, fl, fr but no rr). I replaced the three callipers and on all four I replaced the slider pins and slider grommet thing. These callipers were supposedly in working condition and had been tested before selling, they did look in better condition than my old ones.

First mistake I made as I didn’t realise was that I didn’t depress the brake when any lines were open. I basically just capped it off with a tapered seal/plug and I didn’t lose much fluid at all.

When fitting callipers I noticed the brake hoses were not looking good so I thought I’d replace them while I was there. I replaced four, the only two I didn’t replace were the two rear nearer the middle, quite awkward to get to so decided to leave them and they actually looked in better condition compared to the others. I replaced with stainless steel braided hoses. In the process the rear left short hard line broke and was leaking, so I made a new line with kunifer pipe and double flare ends.

I then wanted to bleed the brakes and replace with new fluid so I got a pressure bleeder and removed the old fluid down to the min line in the reservoir. Then set bleeder to 10 psi to start to see if there were any leaks, no leaks and no pressure lost. Then added brake fluid to pressure bleeder and pumped to 15 psi, left for 10/15 mins, no leaks or pressure lost again. I then proceeeded to bleed all brakes from furthest to closest but each time the brakes were still very spongy, I did this about 5/6 times and the difference seemed negligible. There was air coming out of the callipers when looking at bleeder pipe at first but no more.

So I then saw you could do a brake bleed through ista which I did. It didn’t seem like the full process though. It basically got me to go RR, RL, FR, FL. each corner I would undo nipple then get in car, press brake down, hit continue then you’d hear some kind of pump (abs,DSC?) that would make some noise and put pressure on the pedal against you, close nipple and then it was done onto the next side.. It only did that cycle once on all the corners. So I did it 2/3 times more. Still no difference really when the engine was on and pressing the brake.

I then used the pressure bleeder 2/3 more cycles of bleeding, a few bubbles on the 1st and 2nd. Nothing at all on the 3rd. Still very spongy and when you put your foot down it would eventually go down to the floor.

I notice when I go round the callipers now with the car in neutral and handbrake off one or two of the wheels can spin with some resistance, and the other two, one can be just moved and the other is almost solid on.

So I’m just trying to figure out what to do next? Is there a better procedure to bleed on ista/inpa? Did I do anything really wrong? Could it be the callipers, new hoses or the line I made? Although there are no visual leaks and pressure tested fine?

Ok well this wasn’t short and sweet.

Anyway, any help is appreciated?

Did you follow the ISTA instructions properly?
Your procedure above does not match ISTA instructions.
Those are:
1. Open vent valve
2. Start bleeding with the diagnosis system with open vent valve
3. After completing the bleeding, operate the brake pedal 5 times to the limit position, bubble-free fluid must escape
4. Close vent valve

Your description sounds like you had the 2 and 3 reversed.

I went through some trials and tribulations with my bleeding as well, but the ISTA process worked without problem and I just flushed the fluid again and it worked the first time.

[tcphoto]

I have only done the procedure manually, if you're RHD you start at the furthest caliper and move toward the closest then it should be RL, RR, FL and FR, yes? I did the DIY by myself without issue.

[Processing61]

Originally Posted by eljay

Did you follow the ISTA instructions properly?
Your procedure above does not match ISTA instructions.
Those are:
1. Open vent valve
2. Start bleeding with the diagnosis system with open vent valve
3. After completing the bleeding, operate the brake pedal 5 times to the limit position, bubble-free fluid must escape
4. Close vent valve

Your description sounds like you had the 2 and 3 reversed.

I went through some trials and tribulations with my bleeding as well, but the ISTA process worked without problem and I just flushed the fluid again and it worked the first time.

Ok, yes so I kind of assumed that because I did the pressure bleeding multiple times I didn’t need to do the diagnosis system bleeding procedure and could move straight onto the DSC/abs bleeding procedure. I will check the instructions again.

I just read your comment again. So it seems I missed out the step number 3. So the whole time you are depressing the brake and letting go of the brake for five times, the bleeder screw is open? Then after the five times it is then shut?

Just for a bit more clarity, is this what you did; it says open the bleeder RR etc, then you press down the brake and hit continue to start (it kicks me out of procedure if not pressing down brake at the same time), then you keep depressing the brake pedal and the abs/DSC will pump against you a few times. Then it says press the brake (follow ‘X’ procedure or something). So this is when you would continue to have the bleeder open and press and release the brake 5 times, all the way? Then close the bleeder and move onto the next one, is that correct?

Thanks

[Processing61]

Originally Posted by tcphoto

I have only done the procedure manually, if you're RHD you start at the furthest caliper and move toward the closest then it should be RL, RR, FL and FR, yes? I did the DIY by myself without issue.

So when I used the pressure bleeder, that’s exactly what I did. U.K. so RHD car, RL, RR, FL and FR. But when I had problems and then went to use ista bleed procedure it told me to actually do it in order of RR, RL, FR, FL. which I did think was a bit strange. So I did end up trying the pressure bleeder multiple times in both orders and it was still very spongy no matter what way I did it

[Processing61]

I’m at a bit of a loss with this.

I’ve included a video of what the procedure looks like, kind of seems a bit short compared to what others have said, anyway. So I would set pressure bleeder to 15-20psi check for leaks, then go round each corner (BMW recommend RR, RL, FR, FL, strange I know) and I’ll let some fluid out, make sure no bubbles, then pump the brakes 5 times, again check bleeder make sure no air bubbles and close bleeder. I’ll do that on all corners.


Then I’ll start ISTA, it gets me to pressurise the pressure bleeder to about 20 psi, then open RR bleeder, then press brake and hit continue, then when brake going towards floor you’ll here the abs/DSC pump kick in, push back against you 5 or so times, then stops. Then I pump the brake 5 times still with bleeder open, then I’ll get out and close bleeder, pump brakes a few times and then move onto the next calliper. When I compare that to others it just seemed a bit short but that’s what it’s got me to do. Then I would go round with the pressure bleeder one more time, no ista, just to make sure there are no bubbles, which there isn’t.
https://streamable.com/2xo4cz


Still no luck, included a video of the pedal. It’s very spongy, then hardens a tiny bit and then drops away again until you reach the floor.
https://streamable.com/cz5eh2

I just put the car in drive and you can see in the vid one wheel spins nicely and the other seems to catch and drag, god knows what the fronts would be like. Something just seems really off.
https://streamable.com/nwkexs

https://streamable.com/sr1so6


As I’ve said I’ve gone through about 2-3 litres of fluid so far. So I know it’s definitely clean. No matter how much I bleed it makes no difference, even ista doesn’t make a difference (if procedure is correct).

Reminder; I have changed all hoses to braided stainless lines (apart from two middle rears). I have replaced three callipers with supposedly working and tested ones FL, FR, RL (RL was originally sticking). RR also came off to paint but the exact same one went back on. I replaced all callipers with new slider pins and rubber. The short hard line on the rear left broke so I replaced that. Pressure tests show no pressure lost and visually I can’t see any leaks. I just can’t put my finger on it.

Anyone have any advice? Could the master cylinder or abs/DSC unit broke somehow in the process? Or something else to do with the callipers or lines? Or is the bleed procedure not right?

Thanks

[eljay]

Sorry, I owe you the screenshots from my ISTA process, but I don't recall pressing the brake pedal before starting the ISTA pump activation.

I'll post later this morning

[eljay]

Don't know if there are any differences between ISTA D and ISTA C, but I just looked at your video in detail and if you read the instructions at the start, it does not ask for the brake pedal to be pressed to start the bleeding. I think that is your issue. You press the pedal at the start when you shouldn't and then you activate the ABS pump, but the air has nowhere to escape past the master cylinder, which is now closed. So, some air remains trapped there.

So, try it again, but follow instructions precisely. If the procedure does not ask for the pedal to be pressed, don't press it.

My ISTA procedure is attached, but should be the same as you have.
No need to flush fluid again, just do the bleeding steps starting at #4 in my screenshot or follow your ISTA process.
Attach your bleeder with brake fluid, pump to 15 psi (no need for 20 psi).
Again, the steps as I posted above. The bolded are the exact words from ISTA.
4. Open vent valve
5. Start bleeding with the diagnosis system with open vent valve (this means clicking the button in ISTA, which is the one on top left 1-Repeat Activation, or hitting your right arrow on keyboard as instructed in your version of ISTA. Note: NO brake pedal pressing is requested!) This is where you hear the pump activate.
6. After completing the bleeding, operate the brake pedal 5 times to the limit position, bubble-free fluid must escape. This is where you press the pedal slowly, but firmly all the way down, release. Do this 5 times.
7. Close vent valve


You should only need about 400ml of fluid for the bleeding. That was all I lost while I ran between calipers and driver's seat. So, just put 1L into the bleeder for this.

Regarding your sticking caliper, if you observe this sticking on test drive and lubricated all the sliding surfaces, it it possible that there's corrosion pitting on the piston of the sticking caliper. The only way this would happen is if the rubber boot around the piston is ruptured and lets moisture in or the caliper is corroded and swelled around where the boot seals the piston and lets moisture in and causes pitting on the piston. I always inspect the boots and their sealing area on used calipers. The rebuild kits are cheap and it's easy to replace the seals and boots when you have a caliper out of the car.

Let us know how the bleeding goes.

[Processing61]

Originally Posted by eljay

Don't know if there are any differences between ISTA D and ISTA C, but I just looked at your video in detail and if you read the instructions at the start, it does not ask for the brake pedal to be pressed to start the bleeding. I think that is your issue. You press the pedal at the start when you shouldn't and then you activate the ABS pump, but the air has nowhere to escape past the master cylinder, which is now closed. So, some air remains trapped there.

So, try it again, but follow instructions precisely. If the procedure does not ask for the pedal to be pressed, don't press it.

My ISTA procedure is attached, but should be the same as you have.
No need to flush fluid again, just do the bleeding steps starting at #4 in my screenshot or follow your ISTA process.
Attach your bleeder with brake fluid, pump to 15 psi (no need for 20 psi).
Again, the steps as I posted above. The bolded are the exact words from ISTA.
4. Open vent valve
5. Start bleeding with the diagnosis system with open vent valve (this means clicking the button in ISTA, which is the one on top left 1-Repeat Activation, or hitting your right arrow on keyboard as instructed in your version of ISTA. Note: NO brake pedal pressing is requested!) This is where you hear the pump activate.
6. After completing the bleeding, operate the brake pedal 5 times to the limit position, bubble-free fluid must escape. This is where you press the pedal slowly, but firmly all the way down, release. Do this 5 times.
7. Close vent valve


You should only need about 400ml of fluid for the bleeding. That was all I lost while I ran between calipers and driver's seat. So, just put 1L into the bleeder for this.

Regarding your sticking caliper, if you observe this sticking on test drive and lubricated all the sliding surfaces, it it possible that there's corrosion pitting on the piston of the sticking caliper. The only way this would happen is if the rubber boot around the piston is ruptured and lets moisture in or the caliper is corroded and swelled around where the boot seals the piston and lets moisture in and causes pitting on the piston. I always inspect the boots and their sealing area on used calipers. The rebuild kits are cheap and it's easy to replace the seals and boots when you have a caliper out of the car.

Let us know how the bleeding goes.

Brilliant, thanks for that. The only reason why I held the brake down is because I watched a video that said you had to press the brake and continue at the same time or else it would take you to the start again. That was for a F series car so evidently not applicable here.

Out of curiosity during this procedure is this all that yours did; you press continue and then you hear the abs pump activate maybe 5 or so times and then that is it?

I have followed it exactly as you and ISTA have said and it’s still the same unfortunately. I did it twice just to be sure. So frustrating lol. I don’t have any abs error codes at all but I’m starting to wonder if I’ve funked the whole abs unit and pump assembly somehow

[eljay]

Originally Posted by Processing61

Brilliant, thanks for that. The only reason why I held the brake down is because I watched a video that said you had to press the brake and continue at the same time or else it would take you to the start again. That was for a F series car so evidently not applicable here.

Out of curiosity during this procedure is this all that yours did; you press continue and then you hear the abs pump activate maybe 5 or so times and then that is it?

I have followed it exactly as you and ISTA have said and it’s still the same unfortunately. I did it twice just to be sure. So frustrating lol. I don’t have any abs error codes at all but I’m starting to wonder if I’ve funked the whole abs unit and pump assembly somehow

That is strange.
Yes the pressing brake pedal activations are typically those running from INPA. I had the same problem intil I ran the procedure in ISTA and all went.

I wonder if your issue have anything to do with that sticking caliper.
Since you can hold pressure, it means there are no leaks.

[mweisdorfer]

Originally Posted by tcphoto

I have only done the procedure manually, if you're RHD you start at the furthest caliper and move toward the closest then it should be RL, RR, FL and FR, yes? I did the DIY by myself without issue.

The Bentley Repair Manual has the manual bleed process clearly spelled out in their brake section.

Materials -

•. 9mm & 11mm wrench
• 4 bottles of DOT 4
•. Brake bleeder bottle filled up about 1/3 full so the tube inside the bottle is submerged, as to create a vacuum.

Procedure -

1) the person outside the car opens the bleeder screw and says "open".

2) the person inside the car upon hearing the word "open", begins pumping the brake pedal to the floor 10x.

2) On no. 10, the person in the cabin says "hold", while he/ she holds the pedal to the floor.

3) the person outside of the car, at the brake caliper, looks at the tube attached brake bleeder line and specifically looks for no bubbles coming out or near the bleeder screw. Once this has been established, he/ she closes the bleeder screw while simultaneously the person inside of the car is holding the pedal down to the floor.

4) the person at the brake caliper says, "closed"

5) the person inside of the car then releases the brake pedal upon hearing the word "closed"

6) the person outside the car, adds brake fluid to the master cylinder.

Start with PR first, DR second. PF third, DF last. Do each wheel 3x before you move to the next.

It's a great way to bleed and essentially flush the system.

However, the ISTA D version is preferred; it's a dealer level brake bleed/ flush procedure. This process also bleeds the ABS system as well.

[mweisdorfer]

Originally Posted by Processing61

I'll try and make this as short as possible. E91 325D Msport 2008, U.K.

Rear left brake calliper started to stick on. It's a high mileage car 197k and probably original callipers. Seemed like it was the piston and I was going to replace the whole calliper. I managed to get 3 used callipers (rl, fl, fr but no rr). I replaced the three callipers and on all four I replaced the slider pins and slider grommet thing. These callipers were supposedly in working condition and had been tested before selling, they did look in better condition than my old ones.

First mistake I made as I didn't realise was that I didn't depress the brake when any lines were open. I basically just capped it off with a tapered seal/plug and I didn't lose much fluid at all.

When fitting callipers I noticed the brake hoses were not looking good so I thought I'd replace them while I was there. I replaced four, the only two I didn't replace were the two rear nearer the middle, quite awkward to get to so decided to leave them and they actually looked in better condition compared to the others. I replaced with stainless steel braided hoses. In the process the rear left short hard line broke and was leaking, so I made a new line with kunifer pipe and double flare ends.

I then wanted to bleed the brakes and replace with new fluid so I got a pressure bleeder and removed the old fluid down to the min line in the reservoir. Then set bleeder to 10 psi to start to see if there were any leaks, no leaks and no pressure lost. Then added brake fluid to pressure bleeder and pumped to 15 psi, left for 10/15 mins, no leaks or pressure lost again. I then proceeeded to bleed all brakes from furthest to closest but each time the brakes were still very spongy, I did this about 5/6 times and the difference seemed negligible. There was air coming out of the callipers when looking at bleeder pipe at first but no more.

So I then saw you could do a brake bleed through ista which I did. It didn't seem like the full process though. It basically got me to go RR, RL, FR, FL. each corner I would undo nipple then get in car, press brake down, hit continue then you'd hear some kind of pump (abs,DSC?) that would make some noise and put pressure on the pedal against you, close nipple and then it was done onto the next side.. It only did that cycle once on all the corners. So I did it 2/3 times more. Still no difference really when the engine was on and pressing the brake.

I then used the pressure bleeder 2/3 more cycles of bleeding, a few bubbles on the 1st and 2nd. Nothing at all on the 3rd. Still very spongy and when you put your foot down it would eventually go down to the floor.

I notice when I go round the callipers now with the car in neutral and handbrake off one or two of the wheels can spin with some resistance, and the other two, one can be just moved and the other is almost solid on.

So I'm just trying to figure out what to do next? Is there a better procedure to bleed on ista/inpa? Did I do anything really wrong? Could it be the callipers, new hoses or the line I made? Although there are no visual leaks and pressure tested fine?

Ok well this wasn't short and sweet.

Anyway, any help is appreciated?

If you want to get the middle/ rear section for the SS brake lines, you need to lower the rear subframe. You might have to take it out all together if the case is that the line fittings are corroded.

Put some Kroil Oil on the fittings and let it sit overnight. You might need to use 7-8 sec bursts of heat from a torch, while turning it immediately after you use heat.

You rebuilt the entire caliper(s) by installing new pistons, rubber slide pin seals, & piston seals??

Did you press the new seals in over the caliper seal lip(ridge)??

[Processing61]

Originally Posted by eljay

That is strange.
Yes the pressing brake pedal activations are typically those running from INPA. I had the same problem intil I ran the procedure in ISTA and all went.

I wonder if your issue have anything to do with that sticking caliper.
Since you can hold pressure, it means there are no leaks.

Yes I did wonder this too. But I also wondered on the contrary. All I did on the RR was take calliper off, paint it, put new slider pins and rubber boots in. Replace the hose. It was working fine beforehand. Is it because the system isn’t bled properly that the calliper isn’t working properly? When I checked round the car and felt the resistance of the fronts, it seems like the FL is catching too. Or had noticeably more resistance compared to front FR.

[Processing61]

Originally Posted by mweisdorfer

If you want to get the middle/ rear section for the SS brake lines, you need to lower the rear subframe. You might have to take it out all together if the case is that the line fittings are corroded.

Put some Kroil Oil on the fittings and let it sit overnight. You might need to use 7-8 sec bursts of heat from a torch, while turning it immediately after you use heat.

You rebuilt the entire caliper(s) by installing new pistons, rubber slide pin seals, & piston seals??

Did you press the new seals in over the caliper seal lip(ridge)??

Thanks, I thought that may be the case. I may well do that one day in the future, to do the last two rear hoses. Just want the car working now so I’m not bothered about doing it for now. But thanks!

No, I didn’t rebuild any callipers. I replaced the FL, FR and RL with working and tested used ones. I would have replaced RR too but I couldn’t get all 4 and really the only main problem was with the RL originally sticking. So I didn’t think I would need to rebuild. The only thing I did with all of them are painted them, new pins and slide seals, new braided stainless hoses and one new hard line rear left, the shortest and first one you can see from the wheel well.

[charlie_m]

Originally Posted by mweisdorfer

The Bentley Repair Manual has the manual bleed process clearly spelled out in their brake section.

Materials -

•. 9mm & 11mm wrench
• 4 bottles of DOT 4
•. Brake bleeder bottle filled up about 1/3 full so the tube inside the bottle is submerged, as to create a vacuum.

Procedure -
1) the person outside the car opens the bleeder screw and says "open".

2) the person inside the car upon hearing the word "open", begins pumping the brake pedal to the floor 10x.

2) On no. 10, the person in the cabin says "hold", while he/ she holds the pedal to the floor.

Doesn't this swap #1 and #2 (the first #2 )? For a manual bleed I never open the bleeder valve on the caliper until the cabin assistant has pumped the pedal and is holding it down. That way only new fluid from the reservoir is drawn into the system. The way it's described above it seems like skanky old fluid can be drawn back up into the caliper.

[mweisdorfer]

Originally Posted by charlie_m

Doesn't this swap #1 and #2 (the first #2 )? For a manual bleed I never open the bleeder valve on the caliper until the cabin assistant has pumped the pedal and is holding it down. That way only new fluid from the reservoir is drawn into the system. The way it's described above it seems like skanky old fluid can be drawn back up into the caliper.

If the tube in the bleeder bottle is submerged in brake fluid, it shouldn't matter, I wouldn't think.

[charlie_m]

Originally Posted by mweisdorfer

If the tube in the bleeder bottle is submerged in brake fluid, it shouldn't matter, I wouldn't think.

Wouldn't matter as far as air, but now your bottle has some wet dirty brake fluid in it. Practically it may not matter much unless you are tracking the car.

[mweisdorfer]

Originally Posted by charlie_m

Wouldn't matter as far as air, but now your bottle has some wet dirty brake fluid in it. Practically it may not matter much unless you are tracking the car.

Well, the best way would be to use INPA or ISTA D, for sure 😉

[e91Owner]

Form the video, it looks like the guide pins aren't lubed. Not that that's actually what you didn't do, but something isn't gliding properly.

[Processing61]

Originally Posted by e91Owner

Form the video, it looks like the guide pins aren't lubed. Not that that's actually what you didn't do, but something isn't gliding properly.

Yes, they were all lubed up. But maybe I’ll take the pins out and have a look

[Processing61]

I think what I am going to do is rebuild all the callipers/change the piston and seals and double check all the slider pins. I don’t think it will solve the problem but at least I can be sure they are all good then. Once that’s done I’ll try and re-bleed again. Not really expecting that to work though.

Like I said, no fault codes appearing for the DSC/abs unit but how can I determine if the abs unit and pump and or master cylinder isn’t bad/broken? As if I rebuild all the callipers and I’m still in this position it would be either the abs unit or master cylinder, right? But if there are no fault codes at all to indicate this, it doesn’t seem right.

The only other thing is the inpa brake bleeding procedure seemed a hell of a lot longer than what my ista procedure did. Only 5 or so 1 second activations on each calliper and that was it. Is it worth doing the inpa procedure?

Any help is appreciated

[Processing61]

Originally Posted by Processing61

I think what I am going to do is rebuild all the callipers/change the piston and seals and double check all the slider pins. I don’t think it will solve the problem but at least I can be sure they are all good then. Once that’s done I’ll try and re-bleed again. Not really expecting that to work though.

Like I said, no fault codes appearing for the DSC/abs unit but how can I determine if the abs unit and pump and or master cylinder isn’t bad/broken? As if I rebuild all the callipers and I’m still in this position it would be either the abs unit or master cylinder, right? But if there are no fault codes at all to indicate this, it doesn’t seem right.

The only other thing is the inpa brake bleeding procedure seemed a hell of a lot longer than what my ista procedure did. Only 5 or so 1 second activations on each calliper and that was it. Is it worth doing the inpa procedure?

Any help is appreciated

Anyone have any thoughts on this?^ thanks