aubrey

Deleted

This video is pretty much what I do

On my old 2007 Roomster bleeding from the ABS ports didn't help. Been there, tried that. You need to do the ABS Bleed Procedure with a suitable OBD Scan Tool. An OBD scan tool that does that ABS bleed function, as you know VCDS does too. I did my 2007 Roomster with VCDS. I had to have all 4 wheels off as the procedure on that asks for rear bleed screws to be open too. My newer 2016 Yeti only asks for the fronts. I had a pressure bleeder hooked up as I did the VCDS procedure. The procedure runs asks for bleed nipples to be opened, runs the ABS Pump, asks for 10 pedal presses and repeats that a few times. At each step it waits for you to click to confirm you've done your bit. Finally saying Done. There are some videos on YouTube if you look.

That's how all normal brake fluid changes are done. Yes the fluid does mix a bit and that little bit of un-refreshed fluid doesn't matter. The only time you need to do an ABS bleed is when you have got air in the ABS. I did because I let my reservoir run dry doing a brake bleed and sucked air into the system. Only realising when air splattered out the bleed screw and not fluid, completely my fault, and also when you fit a new ABS unit because the replacement unit would have air in it when installed. I always use a pressure bleeder when doing my brakes.

Also to add "Isn't the pumping hard with the engine off just depleting the servo vacuum though, nothing to do with compressing the air in the system by ramming more fluid in?" Yes, I'm sure it is. But the differance is the ABS unit is off. I can only report the symptoms I had and I think it is because the ABS pump is not in an active state, valves in it closed etc. I can only report what happened in practise until someone with confirmed knowledge tells me why. The thing is if it was seals in the master cyclinder then the same seals would let by with the engine off, yes I can see more foot pressure needed as you'd have no servo assist but the pedal would not be rock solid with hard pressure even with the engine off.

If you fancied a trip down the M11 with a few litres of brake fluid then I'd do the ABS bleed with you. I live in Ilford, NE London. Your choice if you want to pop by. All that would cost you is the brake fluid and the petrol.

I got air in my ABS unit once and I can confirm it causes a soft pedal. The pedal can be pumped hard with the engine off but would sink soft as soon as the engine was started. A little engine start sink is normal, an inch or so due to the servo, but I mean much more than that. Normal brake bleeding won't help but a VCDS ABS bleed procedure immediately cured the issue. You say you've refitted an ABS unit, I would not hesitate in saying you need to do the ABS bleed procedure on it. It is not only VCDS that can do that, many OBD scan tools can do ABS Brake Bleeding.

Is there no-one on the Briskoda VCDS map local that can help you ? I'm in NE London for example and I would.

Why not just copy the coding off your current unit before you disconnect it. Then you can recode as was ? You'd have the current coding on any VCDS scan if you have one saved.

On my 2016 Yeti the original EFB Battery was failing after 4 years. The stop start was never kickimg in by 2020, so 4 years. Replaced it with a Varta AGM battery and that is still going strong 6 years later.

Are you reading an increasing voltage on the Octavia Battery, measured with a jump lead disconnected. Could the battery be bad, possibly a single cell, and as you say not taking any charge ? Are your jump leads thick high current ones or the thinner core variety ?

I agree no one has offered any evidence either way. However I still prefer to play safe and do the coding. No-one has ever said doing the coding is bad in any way.

Also Topdon Carpal looks interesting but I've never personally used that. Looks good value though.

OBD11 or Carista would be cheaper

No idea really. I changed mine to a Varta AGM. so I had to code that due to the change of battery type to AGM. I have VCDS. I'm sure any like for like would do. So EFB+ and 70AH. I don't want to get into brand arguments and does paying more give better value when comparing working life. I'm sure you can go with their recommendation. If not coding then ensuring EFB+ and 70AH is more important for you.