Could be seized internally .. where the piston screws down on the thread? Or it's so far out it's come off the threads!

They can be a real pita and it might be worth buying the proper piston rewinding tool (Sealey)

 

have you undone the bleed nibble on the caliper? (ensure you have suitable tubing and container to catch the fluid)

Most rewind tools advise to loosen the bleed nipple for ease of operation

 

Oh .. one other thing .. you are winding the right way? ... clockwise ...

 

I wasn't winding at all! didn't realise they had to be turned - I'll try that tomorrow. I take it the pukka tool pushes AND turns the piston in? My home-made tool just pushes it.

 

You dont need to rotate the piston, just push it in. Try applying wd40 to the piston, under the rubber seal, leave to soak in for 1 mug of tea and then try again with your clamp. Take cap off brake reservoir and wrap rag around it in case it overflows.

 

you do need to rotate the rear pistons as they go back !!
the front ones will just push back but rears...........nope.........gotta turn them

Gary

 

Wrong -because of the way the handbrake works you need to turn and push the rear calliper pistons in. Never ever used WD40 or any other petroleum/mineral based oil on brake components such as pistons and seals (it will damage them), use only fresh brake fluid or red rubber grease.

 

+1 above, Rears need to be rewound back in. Fronts can be done with a clamp

 

If your having problems and it's tight, get some one to pump the piston out, disconnect the flexi hose and plug it, then give the whole unit a clean using brake fluid (with the seals removed) and a green pan scrub on the piston and caliper housing which will remove crud and scale without marking....you can easily reassemble fill and bleed the system and know you wont end up with seized calipers!

John

 

+1 for Blueji

 

Also dont know if this has been said... slightly unscrew the Brake Fluid cap under the bonnet to release the pressure, lets the level rise with out the pressure being against you, just be careful the fluid doesnt over fill as you wind in.

 

Good point,especially if someone has topped it up as the pads have been wearing down.

 

I tried using thin nosed pliers to wind the piston back in, no good.Bought the correct tool by laser and it was a doddle.

 

Yep, using the correct rewind tool makes it such a simple job.
There really is no point trying to do it any other way, you will only get frustrated and probably end up buying the rewind tool anyway!

 

I've got exactly the same problem......

Is this the rewind tool you guys are referring to...;

http://www.halfords.com/webapp/wcs/...langId_-1?cm_sp=Intelligent_Offer-_-Product_Details_Zone_1-_-Blank&iozone=PDPz1

BUT I don't get how this fits onto the piston tho - there's nowhere for these noddules to sit into?

 

Yes, that's one that will work. Saw one for £20 in Halfrauds the other day. They do work. Just spent the afternoon doing brake lines, disks and pads. The rewind tool makes life much easier. There are two slots in the piston, the nodules as you call them fit there. The bit which pushes the piston back in is reversible, so if one side doesn't fit, the other will. It will become clear when you try it.

 

Cool - I've just reserved at the local Halfrauds (;o) - I like it!!) . Try again tomorrow!!

 

That just happened to me today.
I had the rewind tool, but it was bloody hard to move!
After 1 turn it wouldn't move to any side, dropped some grease inside the gaiter, even tried turning with a large wrench, no way! The wheel's bolts had been butter in comparison! :lol:

I had a genuine TRW caliper rebuild kit, just in case, so I decided to give it a try.
Was a child game, in 25 minutes I had both done.
And could rewind the pistons with just a finger!

 

The rear calipers do get sticky. I replaced my nearside one for £80 as the piston had corrosion after the gaiter had failed because the piston twists. Didn't realise there was a refurb kit. Would this have had a new gaitor for the piston as well as new pins and sliders?

 

There's a very good pdf guide for doing the brakes. Unfortunately my computer skills are stopping me from uploading it but googling "156 brake fitting guide" it was the first hit. The guide is very good.
Using the correct tool makes the job easy. I bleed from the nipple. The discs improbably fit without the need to remove the carrier which makes the job pretty easy.
Sure you'll find this easy with the rewind tool. I regret not buying one earlier when I did the rears on a saxo I used a g clamp and a 5mm square bar into a slot on the piston to do the twisting. Took forever.

 

You must rotate or you will **** the pistons. Get a laser rewind tool from eBay, about £18. It has little spigots that match the holes in the surface of the piston. Unscrew the reservoir cap or you just won't be able to do it. As others have said you can try bleed nipple opening- connect to a pipe to avoid spillage!

 

https://www.alfa156.net/tech/Alfa156Brakes.pdf

Guide

 

Mines were hard as rock, even attaching a large spanner to a donkey wouldn't move it. As I said, new gaiters/seals/grease made a huge difference
Last week I took the rear caliper apart for fixing a noise (applied a bit of copper grease on the edges), I still could rotate them by hand!

 

New calipers are easy to wind in.
Make you realise how bad the old one was when you try a new one!