Technical brakes fading

[kein1]

hi everyone , i have a fiat ducato 2008 front wheel drive , auto , jayco motorhome and i am having trouble with the brakes , when i put my foot on the brake pedal to stop the pedal slowly keeps going down , it has only just started , i try pumping it but will not pump up , brakes do work slowly , have looked under van but cannot see any leaks in the lines , have put new discs and pads 3 years ago , back brakes look ok , could anyone give a hint as to what the problem could be , many thanks

 

[varesecrazy]

Hi

Potentially the servo assistance has failed internally

A test :

With motor warm

Turn OFF engine

Pump brake pedal until FIRM.. hold your foot there 'lightly' for 1 minute

Press HARD.. does the pedal drop further.. or still FIRM ?

KEEP foot on brake..
Start engine.. does the pedal drop a little ?

Let us know the results

 

[jackwhoo]

With engine running can you hear a hissing noise if you put your head in drivers footwell?

If yes does pressing the brake pedal stop the hissing noise ?

I had a partly failing brake servo giving the above symptoms. The brake pedal was very firm indeed but required more effort than normal to stop vehicle because vacuum couldn't build in servo unless the pedal was pressed.

The only fix was to replace the servo.

Another clue was the servo didn't hold any vacuum after the vehicle was stopped for any length of time.