Rear Break Pistion Would Not Depress

[maysani]

Dear All,

I tried to replace rear break disk and pads today (for my Galaxy 2003 1.9 TDI) but I am stuck, cannot get the break piston to depress so that I can fit the new pads. I used brand new rewinding tool  with 19  mm socked without success. I open the open vent screw and there were some beak oil came out, put the piston did not move. Any idea please

sorry my have posted this question in different section if this forum   

 

[daddyfixit]

possibly rear caliper has failed internally---mine went 2 weeks ago;   I thought handbrake cable had snapped but it was the handbrake mechanism inside the caliper.

[sparky Paul]

If the pads and discs are really worn, the piston can disengage from the handbrake adjuster screw. Because the piston is at it's fullest extent, it can then cock slightly and jam in the bore. Try rotating the piston in the opposite direction to free it, then ensure that the piston is square in the caliper before applying the wind back tool.

 

Failing that, you will have to take the caliper off so you can take out the piston and see what's going on in there.

 

Also bear in mind that the piston can be quite stiff to turn when extended, particularly on old calipers.

Edited May 29, 2016 by sparky Paul

[maysani]

Paul,well done and many thanks, indeed the piston was disengaged. I am facing another challenge now, how to top up the break fluid, where can I allocate the break oil resvoiure. is it the one behind the air filter, if so, do I need to take off the air filter to top it up? 

[sparky Paul]

The brake fluid reservoir is behind the air flow sensor (MAF) and pipe to the inlet manifold. It's the most stupid thing on the car, why they didn't fit a remote reservoir I do not know.

 

Easiest way to access is to unclip and remove the air filter box lid. Then unplug the two connectors from the sensors, undo the jubilee clip on the manifold end of the pipe and remove the inlet pipe complete with the MAF.

 

It's still awkward to get to, but you can get to it.

[tamworthleon]

Was going to say you are screwing the rear pistons in and not trying to push them in?

[maysani]

tamworthleon ,

this is what I did in sequence:-

1. turned the piston  half a turn anti clockwise
2. took the piston completely out while the calliper still connected
3. made sure that the rubber sleeve is not damage
4. put the piston back with couple of turn clockwise
5. used the piston  rewind tool to push it all the way back with ease
6. bled the brake