Changed the rear cyclinders on my Octy mk1, bled the brakes but is still spongy, want to bleed the abs unit but don't have VCDS.

 

A garage have quoted me £100, is this steep?

Are you sure the ABS needs bleeding ?   That should only require doing if you run the master cylinder dry and pulled air though the ABS.   Just changing the rear cylinders should not of caused that, even with a bit of dripping from the open brake pipe there is a long was to go until air got up to the ABS.   Quite often when putting a dry new brake caliper on a car you have to unbolt the caliper and move the unit around while using an Ezibleed to flow fluid though. It is because often the bleed nipple is not right at the top and some trapped air remains.  Could the same issue occur on a cylinder (drum brakes? ) and you could try bleeding the cylinder unbolted with just a flexible hose attached.

Although thinking about drum brakes I've done in the past (it is going back a few years) there is not a flexible connection actually at the cylinder.

I'll watch this thread as to how you get on, I did have to do the ABS Bleed Procedure on my Roomster and it does take a bit of time

https://www.briskoda.net/forums/topic/439265-vcds-abs-bosch-80-brake-bleeding/

A full brake bleed from a garage near me costs £50, so with them having to do all the extra work regarding the ABS Procedure could add another hours labor.

Unfortunately you are not that near me otherwise I would of helped you with the VCDS function, but are there no closer members if you really do give the ABS procedure a whirl.

I'm not 100%, I had a fluid leak from a rear cylinder, other had bleed nipple snapped off so unsure when/if that was bled, the brakes have never been that sharp since buying the car last July.

The first I was aware of the leak was when going round a roundabout the warning light and buzzer came on, I'm not sure if this will have introduced air into the system?

All I know is the brakes are worse than they were before but have improved slightly with driving, been trying to activate the auto adjusters on the handbrake but doesn't seem to have adjusted much, would this affect the pedal?

 

I used the two man method to bleed making sure the pedal didn't travel to the floor.

I gave the rear brake pipes an extra nip, they seem old and didn't want to overtighten/snap them.

I have a pressure bleeder but last time I tried I couldn't get it to seal properly, I am going to try again at lower pressure using a bike inner tube to pressurise it.

I have a cheap ebay vcds cable with the shareware software that lets me manually look up stuff and actually let me activate cruise control which I was surprised about.

I noticed in a Haynes manual once it said to help bleed air from ABS modules to bleed the brakes in tandem(both the back brakes together) and then do them individually again.

 

Worked for me when I had a similar issue.

I did what VCDS told me to do. Actually it does say things like "Open FL + FR nipples" for both fronts and "RL + RR" for both rears. However I think the ABS unit is opening and closing various internal ports and activating the pump in coordination with its bleed nipples open and close requests.

When you look up the abs unit in VCDS, what ABS unit does it record as fitted to your car?, MK20 or MK60?, as the bleed sequencing is different depending on the system, and can cause small airlocks if you don't follow it.