Golf 7 1.2 TSI 2014: permanent brake friction

[svetly]

Hello Volkswagen Club Sweden!

Wondering if english is acceptable here. Apologize if it's not ...

Being an owner of rather simple Golf 7 2014 1.2 TSI Manual since 2017 December, would like to describe a problem I've been having headache with and it's still not resolved.
During 4 year journey the car ran from 58800 to 153900 km.
Somewhere in the middle I noticed rear left brake has permanent lite disk/pads friction. In all driving conditions it's significantly warmer than 3 other disks. Even after engine braking stop, with no brakes applied, disk is hot 40-50C, while others are cold. In terms of wear-tear braking resource on this wheel is significantly shorter than others.

Here are a few key entries from my protocol:

2017-12-29, 58800km, car bought from VW Göteborg - DinBil Grafiska vägen

2019-03-20, 86500km, reak brake pads are worn out, left one is more, left disk has significant circular relief

2019-05-08, 92400km, rear brake disks and pads replaced in workshop, Fairbilservice Tackjärnsgatan 8 Göteborg

2021-04-01, 138400km, first facing problem and realizing it's a problem. Left rear disk is super hot after slow and short drive, shining red in the dark, sounds like a sauna heater. Caliper piston is stuck, not going back. I cracked it with piston compression clamp. Put some lube under jacket, brommsfett on the caliper holder screws and copper greese where pads touch the caliper. Feels better but still lite permanent friction.

2021 Bilbesiktning - no remarks

2022.01.29, 152790km, piston stuck again, extreme disk/pads friction, disk noise again like a sauna heater. Replaced both rear calipers, disks, pads, brake fluid. Still low permanent friction on rear left, dismantled a few times, nothing helps

2022.02.07, 152800km, replaced front disks/pads. First time after car manufacture!

2022.04.02, 153890km, low permanent friction, new rear-left disk already has familiar circular picture, others are completely clean


When the car is lifted on stand, I lock/unlock electronic parking brake, it's hard to spin rear-left wheel by hands, and while spinning it doesn't go easier, more or less same force all the time. Rear-right wheel spinns much easier. And, as mentioned earlier, while driving and engine braking I make a stop, rear-left disk is warm, others are cold. Surfing internet, questioning friends and colleagues doesn't give a result. As far as I understood, nature of "un-braking" has to be related to the internal o-ring seal elasticity together with spinning disk surface runout while car is going. I appreciate any comments, hints, etc.
If you're located somehwere around Göteborg - Stennungsund area, I'm ready to come by, talk, show
It's become a little hobby and a sports interest for me to fix this little, rather old but still well going car, it deserves longer life.


Kind regards
Ilia

[NissePisse]

If nothing else helps (you already have replaced calliper) then it could be the brake hose.

[Mex165]

Or a sticky valve in the abs pump..
Emergency brake not calibrated or EB-motor.
But if all the brake fluid has been flushed, system tested/flushed via ODIS or vcds... Then all should be working..