Sinking brake pedal
QI have acquired a 2006 Ford Ka Luxury 1.3 with ABS and the two lines outlet master cylinder. The brakes are visually in very good condition with pads/shoes and discs/drums not long changed by the previous owner.
The problem is a sinking brake pedal every time the brakes are applied, I decided to change the master cylinder, but couldn’t find any new aftermarket items, so I took a chance on a used one. After fitting and pressure bleeding from the furthest wheel first, there is no change from the old unit.
I tried clamping all the flexy hoses, but the pedal still sank. It doesn’t collapse straight to the floor, but you can work it down quite low by pulsating the pressure you applied.
Could a faulty ABS unit give the same symptoms as a faulty master cylinder? I did find a Ka owners website that says to find out the bleeding method for ABS you have to contact a dealer. I’ve always managed to bleed brakes successfully in the past, normally getting a very good pedal, so their comment surprised me somewhat. Obviously, I might have just bought a worn unit but would appreciate your opinion before going further.
In addition, there are no stored or pending codes for the ABS unit. I did check with my Foxwell code reader – although I did have to go into Ford USA for it, but the ABS light is NOT illuminated either, so
I think the info is reliable.
Dean Savage
A
The symptoms you describe are those of a master cylinder failing and allowing fluid past the seals. As you have clamped the hoses you will have eliminated one of the problems which has been associated with the Ka – a leaking thread between the rear brake hose and wheel cylinder, although this problem was rectified on vehicles built after 2002.
I would not suspect the ABS unit as this would normally give different symptoms and the Ford manual gives no special instructions for bleeding the brake system which would suggest that no valve operation needs to be carriedout during bleeding. This would lead me to suspect that the replacement master cylinder may well be suffering from the same problems as the unit it replaced.
Although I did find a master cylinder available from this website http://bit.ly/ Cmc5bmc I was surprised at the £300 price tag. The jump in price for vehicles fitted with ABS is quite dramatic.