We had a weird one yesterday, large Irish woman client complained of no brake pedal pressure after about 45 minuets so guide swapped with his and pumped up the pedal and behold, brakes again, 45 minuets later the same lady complained of the same thing in the second vehicle, so again swapped the vehicle back and guide pump the pedal and brakes again.
The only thing I can think of is that the woman was driving with her left foot on the brake pedal and 'boiled' the brakes so when they cooled down during the swap over period they worked again.
Anyone else had brake fade or overheating problems.

We have now THREE rear brake /handbrake calipers leaking with the resulting no brakes, of course this presents starting problems as the brake has to be applied to start. Also, despite being tandem master cylinder, if the rear leak the fronts are pretty much useless. not what I would expect at under 1500Km.

I have found a great many cars use 38mm seals (with internally fitted dust seals) Fiat 124 in my case but also VW, Audi, Lancia, new beetle etc.

We had some issue's with 2016 U Force losing pedal due to the MC. Never an issue with a ZForce.

If the brake pedal had her foot on until it boiled the fluid I would expect some damage to pads & rotor's, these brakes don't take overheating very well.

If these units are using the same rear caliper for hand brake & wheel brake my experience is factory does not adjust the cable properly & they will drag. Should that be the case then yes it will over heat & cause all kinds of problems.

Yet another one, this time warped the alloy cylinder so new seals didn't fix it, so $300 and off the road at 300€ a day., thank you.
The pads are definitely on the blue side so I suspect it was getting VERY HOT. Hand brake is of course not binding and as it is automatically adjusted I would suspect driving with the brake on or the left foot on the pedal instead of staying on the foot rest!  Need to increase awareness at the per-tour briefing. Also considering hooking up the buzzer so it sounds with 'in drive' and 'brake on',

The rear calipers are becoming a serious safety problem. We have had 6 rear calipers overheat and distort with fluid pissing out, so no brakes!
I have fitted new 38mm sealing rings but 3 of them are so bad that doesn't work and they still leak and we have had to fit new calipers, I am awaiting on 3 more to arrive so two buggy's off the road.
They get so hot they burn the dust seals to a crisp!
This is a serious problem now with two crashes, one bending the right steering arm 2" upwards and the rod end bent too.
I have had to disconnect all 11 hand brakes to see if clients leaving the brake on is the problem, if that doesn't stop it then we need to look at left foot driving re-education.
If it does stop the heating then a buzzer will have to be wired on parallel with the dash brake on warning light.