(Sorry for the childish title, couldn't resist.)

Whilst trying to change the front discs and pads, we changed the passenger side no problem, but when it came to doing the driver's side, the pressure in the caliper and/or fluid lines was so great we couldn't force the thing back to get it on, even with the correct tools.

 

Seeing as my brake fluid resembles marmite (I've only had the car 3 months, don't judge me) we figured we'd change that at the same time - simple enough. However, the bleed nipples on the fronts all seem to be completely seized (and whilst I've not had the back up yet, I have no reason to believe that they'll be any different). I cant get hold of PlusGas - tried everywhere - so does anyone have any genius ways to reduce the pressure in the system enough for us to be able to get the caliper back in place etc?

 

Any help gratefully appreciated, I need to get this job completed and get it into the garage by Thursday next week.

 

Cheers guys.

Order some bloody PlusGas online already. Its been a week or more since you wanted some... delivery is only a few days!

 

And I doubt its pressure preventing you from pushing the piston back unless the line is blocked stopping fluid returning. More likely corrosion on the piston.

You did remove the lid from the expansion tank? And you are using a rewind tool? Mine wouldnt move until i did that and used that tool!

 

You could try WD40ing the unit and leaving it for a bit? I had to do that when i replaced my rears as nothing would move.

+1 on removing the brake fluid cap

We did take the expansion tank lid off and do it with the rewind tool, yeah... piston went so far and then just would not budge :/

 

DanHarper, you're right - shoulda ordered it last week! since I posted this I've found somewhere that does it next day for £4 so we'll see if that helps.

And you are using a rewind tool? Mine wouldnt move until i did that and used that tool!

 Rewind is for the rear as it has the handbrake gubbins in it. Fronts should push in.

 

I'd be removing the rubber bootie and checking the state of the piston when you get it off.

 Rewind is for the rear as it has the handbrake gubbins in it. Fronts should push in.

 

I'd be removing the rubber bootie and checking the state of the piston when you get it off.

+1 

We did take the expansion tank lid off and do it with the rewind tool, yeah... piston went so far and then just would not budge :/

 

DanHarper, you're right - shoulda ordered it last week! since I posted this I've found somewhere that does it next day for £4 so we'll see if that helps.

work the piston back and fore it will go

Also, don't put the manky bleed nipples back in (don't know why people do this, really), new ones are pennies from any decent parts place.

http://www.ebay.co.uk/itm/141647242363

 

Plusgas if you can wait a couple of days

Does anyone have the size for the bleed nipples??

 

These are off Skoda...£6...each but no size given.

Edited 16 June, 201510 yr by bigcats30

M10, 1mm pitch according to this page for a 2005 vRS fronts (item 5).

On a guess, and it is a guess, M10 at the front, M7 at the back. Give it a search. They cost pennies though, go to a parts place and get a few of each metric size.

On a guess, and it is a guess, M10 at the front, M6 at the back. Give it a search.

I did but the threads I found never gave a definitive answer 

 

However what Wino came up with agrees with the skoda parts website so thank you Wino.

 

Front = 357615273  M10X1

 

though it doesn't say what the rear are or give the part number that the Skoda website recognises

Hadn't thought about putting fresh bleed nipples on but I'm not paying £6 each!
Got some plusgas now and I've left it to soak so hopefully some progress, cheers all.

 

Don't think it can be piston corrosion though as the piston's covered in grease and it moved part way and then refused. Hopefully it's just pressure build-up...

Have a look at this page about master cylinders.  It's based on Hondas, but I'm pretty sure that's irrelevant. Lots of nice, colour pictures of different stages in action.

 

The very first picture shows with pedal un-pressed: see how there's an open connection between each circuit and the reservoir; the "fluid intake and return port"?

If all is well, that should be letting fluid come back into the reservoir when you push the piston back (assuming no airlock above it caused by cap left on reservoir). 

It's improbable, I'd think, but possible, that what's happening is yours isn't open, because the pedal isn't fully up?  If you get an assistant to put their foot under the pedal and lift it while you attempt to push the piston back, you might be able to rule this idea in or out?  I can't see any other believable mechanism for there to be a 'pressure build up' with pedal not pressed.

 

Good luck with all your nipples.

Hadn't thought about putting fresh bleed nipples on but I'm not paying £6 each!

 

That's for genuine Skoda ones. You can buy bleed nipples in normal car parts shops, much cheaper.