cilo 172 abs brake problems

[winni90]

Can anyone help please. Basically when I get to 60 mph n doing around 4000+ revs brake pedal goes hard therefore cannot brake and sometimes abs light comes on and other times it doesn't.
all abs sensors r ok as I have had it on diagnostics. I have also taken abs fuse out to test and brakes r fine so it is an abs problem. Running out of ideas any suggestions please wud be appreciated. Ta

[Matt Seabrook]

If you have put it on diagnostics and still have not sorted it, it might be a good idea to book it in to a garage if the brakes are not working properly. Sorry its not what you want to hear but better than may be ending up in a ditch the wrong way up.

[PaulKemp]

Check for vacuum leak to servo
Breaks will usually fail safe unless there's a fluid leak then one circuit should still work
Vacuum leak = no servo=heavy brakes

[MG CHRIS]

Check the abs reflector rings on the driveshaft's very common for cracking and sometimes doesn't bring up a code. Other than that the brakes need to be checked over.

[bearman68]

Sounds more like control issue in the ABS unit. Heavy brakes = stuck solonoid or not operated assistance pump. Worth checking the pump from the scan tool and actuating it manually.

[thehammer]

PaulKemp said:

Check for vacuum leak to servo
Breaks will usually fail safe unless there's a fluid leak then one circuit should still work
Vacuum leak = no servo=heavy brakes

^^^^This