Help I popped a Piston (brake )

[fazersharp]

I was being very careful but just over estimated how much I could pump them out to clean and one popped out, not a lot of fluid came out and I managed to get it back in ok.
And do a good job of cleaning.
The reservoir did not empty so no air got in from the top. Calapers and pads back in and re attached to forks, I have pumped the leaver and but obviously its going to need bleeding.
But will I have to do both sides I am thinking that the other side will be ok.
If it matters its braided lines two piece via a double banjo at the reservoir
I am dreading undoing the bleed nipple for fear of it snapping, I have some penetrating liquid sitting on the thread.

[Grahamm]

I'd suggest the best thing to do (presuming you can slightly loosen the bleed nipple without it breaking off) is to take the calipers off and hang them up above the master cylinder to let the air bubble up to the highest point.

Put a piece of wood between the pads, then open the bleed nipple and pump the lever to get all the air out.

Top up the master cylinder and you should be sorted.

[fazersharp]

Thanks Graham.
The calipers were not that dirty but here is an after and before

[fazersharp]

Well fingers crossed it seemed to have gone well, too well in fact so much so that I don't trust it.
The bleed nipple undone without putting up a fight and a few pumps and out cam these beautiful bubbles 
The leaver feels like normal and I pushed through 200ml of fluid, I kept going a while after I thought the bubbles were out.
Do people think I should still tape in the leaver overnight

[Grahamm]

Taping/ tying in the lever is only a temporary fix.

All it does is to force the air back into the brake fluid, temporarily making the brakes feel firmer, but it will eventually bubble out again, leaving them spongy.

The only real solution is to leave it out and make sure that you've actually got all the air out entirely.