Ford Escort Estate Front brakes binding - three problems

[freddie43]

Hi. I have a 1999 Ford Escort Flight Estate 1.6 Zetec engine

Three problems with front brakes. I have replaced pads, disks and calipers

1) On a frosty morning, when I brake, the front brakes lock on and take an age to unlock. Turning off engine, depressing brake pedal hard and starting engine often helps. Or just waiting 5-10 minutes

From the boards it looks like this is:
a) water in the brake fluid freezing
b) faulty front brake hoses

So I will replace the fluid and the hoses

2) Driving along, not touching the brakes, the front brakes progressively come on and bring me to a grinding halt. This was very alarming on the M1 the other day! Solution as above, but what is the cause? Master cylinder? But how?

3) Other times I can be driving along and I notice that the brake pedal rides high - only needs a touch to bring the brakes on. That is a warning sign that the front brakes are going to seize. Solution as above, but what is the cause?

Any suggestions gratefully appreciated

 

[Whitworth]

Perhaps a fault with the internals of the brake servo or maybe a worn or broken return spring in the master cylinder allowing servo to operate the brakes without driver input?

 

[freddie43]

Perhaps a fault with the internals of the brake servo or maybe a worn or broken return spring in the master cylinder allowing servo to operate the brakes without driver input?

Thanks for that. Very interesting. I have thought it must be something in the servo - maybe the actuation, but haven't been able to find out how it works. Your suggestion certainly fits the facts. Thanks again. Pity servos are so expensive!

 

[Burnerman]

Presumably the pedal return spring is intact?
I've no idea why this has a connection to frosty weather though.....if you have replaced the calipers then you must have replaced the brake fluid!
John