Hello,
I have a 2006 model Croma 1.9 16V vehicle.
One existing in Turkey. It also means me.
Fuel tank cap does not work I'm looking forward to the broken wire inside the tank cover part of the push.
I would like help where I can buy this piece.
Thank you.

This is a common problem.

You can only buy/get the whole unit.

Fiat P/N: 51734821 costing about 45 Euros

Thank you for the information.

For the time being I have given up with mine

I have left the push/plunger assembly in place and not use my fingers or a little rubber sucker to open the fuel filler flap.

The flap closes flush and can still be opened. Not as easy/convenient as the pop-in/pop-out push method but a whole lot cheaper for something that will fail again.

I'm on my 3rd unit and all have failed due to corrosion of that thin "hair spring pawl". Last unit was filled full of water resistant silicon grease and even this did not survive.

The pawl spring should have been made out of stainless steel. Would have cost Fiat less than 1 pence (0.01 Euros) for manufacturing production runs.

You're right, there's a bit of quality problems.
But I love my car, I ordered a new one.
Thank you for your interest.
Greetings.

When the new one arrives remember to pop the plunger out and liberally fill the cavity with waterproof grease.

ALSO liberally smear the plunger pawl spring and carrier with the grease. I accidentally skipped doing this so I suspect that whilst I filled the plunger cavity with grease the pawl spring was left uncovered and started to rust as soon as atmospheric moisture penetrated the assembly.