S40 brakes fade

[Yairbel]

Hi, I have my s40 2012 T5 and I had an issue in which there was no pressure in the braking system (pedal to the floor) during a drive I had. I checked it and saw that I had an issue with one of my rear calipers which I thought affected the ABS system which caused me the issue, moreover, the brakes worked better when I pushed the pedal rapidly with force. I also replace the brakes hydraulic fluid and checked if there's air in the system which looked like there is no.

However, after the calipers fixup the system still wasn't working fine for me yesterday by the same way, and I had no braking pressure. I used the handbrake since the brakes itself works fine, and after few pumps the brake returned to work just fine.

Now in both off the occasions it was a very hot day (35-40c) and I do think there's a connection to this. A friend of mine suggested there's a problem with the ABS modulator since it happens very rarely but it feels wrong, I can't the the connection to the heat. Does anyone experienced that and have some ideas?

[IainG]

Hi
Surely if the pedal goes to the floor it can only be either air in the system or a master cylinder fault? The ABS just stops pressure reaching the callipers and doesn't affect the operation of the master cylinder.

[Yairbel]

I was expecting the power loss to be continuous and not to be temporary or dependent on the power or speed that I apply to the pedal...