Did a dumb thing today (its Saturday here) Went to change the disc pads on the back of my Cossie 4x4 and thought it won't take long so I jacked it up in front of 5 customer's cars in our shop and then discovered that winding back the piston in the caliper was not the easy job I thought it was. Haven't got the right tool, guessing it needs to be turned clockwise, found out it was important to have the hand brake disconnected to allow the operating arm to swing right back and whatever I do cannot get the f*****g thing to go back, now have torn the rubber gator. Does the piston need a constant pressure while it is being turned? Am in the shit now as I cannot move the car as there is a deep gulley drain at both ends of the car so cannot move it out the way and five customers need their cars Monday morning.

Heeeeeeeeeeeeellllllppppppppppppp

 

I have answered your PM,
tabetha

 

Horrible job! I just did it recently. You'll need to get under the car to slacken the handbrake cable off. Once you're under there (WITH AXEL STANDS) you'll see the cable is just loosened with plastic things that you can turn by hand.

And try to borrow a caliper wind back tool. If you don't have one you can do the calipers using a plumbers grip but its slow going.

And you can always move the car around as long as the wheels are on the car.


Charlie

 

Is it only on 4x4 you have to slacken the Handbrake Cable because I've never had to do that to my 3 door and i've changed the pads loads of times.
Rich

 

a correct wind back tool applies pressure to the piston to wind it back if ot not winding back try realeasing the brake bleed nipple and make sure you have a pipe on it to drain the excess fluid away if its still not going back i'd say the piston is siezed

 

Thanks guys I should be OK now

 

hi mate, you have pm

 

assuming you have removed the rear caliper from the hub and it is now only connected via the brake pipe and the handbrake cable, do this:

inside the car, let the handbrake off
this will move the pins back to their original stops (although if the handbrake is on, the rear caliper shouldn't be able to come off the disc)
open the fluid resivour to stop any fluid backing up and stopping the piston from retracting
you need to have pressure on the piston while you turn, hence the windback tool is required for some jobs
the piston is pushed out by fluid pressure
the handbrake relies on a thread inside the piston that turns as you apply the handbrake
this also accounts for the autoadjustment
and this is what you need to overcome to get the piston back
remember also that there are 4 grooves in the piston that need to line up (one of them in anycase) with the little pin that sticks out of the middle of the pad

once you have spun it back and lined the pins up, you can put the pads back in
once everythign is done, turn the ignition on so that teh abs pump primes, then use the foot pedal to push the pistons out (on both sides) until they stop the disc from turning
once the piston is out in it's proper place, then use the handbrake to tight it up and set itself

once the piston starts to go back, it will be easy to keep it going backwards

 

just read the above thread and think i have just figured out why my handbrake is shit and my abs light is on!

 

OK just learnt something I didn't know or realize was important. The lining up of the pin on the back of the pad, makes sense, I will have to take it all off now to see if by luck, the pin is lined up. Thanks again.

 

the pin is there to stop the piston from rotating when it the handbrake is applied, htis would mean that the piston would retract in on itself rather than push itself out

if they are not lined up and the piston is as far back as possible, you can twist the grooves into position with some pliers

 

Thanks guys. This thread saved my mondeo and my mind!

 

the other complication is that the threads on the windback tool are different to the threads on in the caliper, which may explain why you have to tighten it up every few turns in order to get it nice and snug again