I'm no mechanic, but that sounds like far too much of a coincidence!. The garage clean the brakes then the ABS stops working, hmmm....!

But, and it is a big one, if the ABS was not working, i'm 99% certain the warning light on the dashboard would be lit up. If, as i am assuming this to be the case, then it wouldn't be the fault of the garage that your partner went off the road. Which brings me to my next point, for your partner to go off the road like that regardless of whether or not the ABS was working, suggests one of two things. A, he was going too fast for the conditions, or B, there was oil or something spilled on the road. Cars don't just "start to slide" for no reason.

One last point (and i'm not 100% sure on this), i think when new tyres are first put on, you should drive extra carefully, to 'bed them in' (so to speak). So this may well have also been a factor.

Edited by badbusdriver on 04/10/2019 at 19:34

My thoughts are spilled fuel or other slippery substance on the road, or new tyres needing to be driven for a while to get full grip, or he was going faster than he imagines he was for the conditions.

The brakes shouldn't lock up as such on a modern car fitted with ABS, they do lock momentarily of course but if you keep the pressure on the brake pedal the ABS kicks in and applies the brakes repeatedly faster than a driver could, releasing for a fraction between applications as soon as slip is detected, you feel this as a rapid pulsing through the brake pedal.

see we have the same initial thoughts here BBD.

Edited by gordonbennet on 04/10/2019 at 19:40

You'll probably never know, but if you thought the black hand was acting shifty, then he probably was.

IF there was a mechanical fault that locked one or more brakes up (for example, a hose acting as a non-return valve) I don't see how ABS would help.