rear caliper piston removal

[1983Pinin]

I'm redoing the entire brake system on an 83 Pinin and am stuck at the point of removing the rear caliper pistons. I farted around and pulled the threaded rod and spring washers out the back. I know this is back asswards, your supposed to screw out the piston first using your handy file as a screwdriver.
My question is if the bolt is out of the back of the piston can i push the piston out by pushing it from the back? I have a masonry bit that seems to fit -- yes, not putting the bit end in-- the blunt end.
Can I put the bit in through the bolt hole and pound it with a hammer to get the piston out? They do turn don't seem rusted but a tad beat up from my vise grips. I shot WD-40 in the bleed line Nd kept them upright for Wd-40 to work.
--Peter

[jlw35]

I did exactly that on my recent rebuild. The piston was jammed so I soaked some PB blaster overnight, tapped it lightly the next morning and out it came.
Jeff

[1983Pinin]

Thanks Jeff,

You've given me hope!
So it was pretty easy getting it out? What did you use to poke into the hole and to bang out the piston?
I've seen the posting where the guy shows all the parts removed from the rear caliper, but without seeing the underside of the piston I worry about what I'm banging up against. If I get it out I'm going to post a picture of the back side of the piston. I'm guessing it's just a threaded hole in the center??
Both of my pistons do turn if I grab them with a vise grip , but not very easily. They're also both bottomed out at the moment-- no piston body showing, just the smaller front surface . I can easily grip with vice grips, but really because don't want to continue like that because I'm chewing them up a little bit and don't want my care parts looking like I'm a hack!
So wish me luck. It was WD-40 overnight this time. If I don't get them I'll move to the PB Blaster for another overnight soak.

Then my next challenge-- separating the flexible brake lines from the steel brake lines so I can replace with braided SS flex.

--Peter

[jlw35]

Peter,

flex line and solid line for the brakes are actually pretty easy. Use a flare nut wrench on the metal brake line and a crescent or crows foot or vise grips to hold the nut shaped fastener on the flex line. They will separate pretty easily, but you have to be sure to have a firm grip on the end of the flex line so that you don't twist the hard brake line. I think that sentence makes sense?

Sounds like the piston may be stuck due to one of the 2 (or both) rubber seals maybe twisted or mis-seated? Probably the PB blaster is of no use in that case. I used a wooden dowel to tap on the back of the piston. I would be careful because the back of the piston has the threaded hole that the rod screws in to. It has some play in it as if it is slightly spring-loaded. If you need something with less give that the wooden dowel, you could use a screw driver and tap out to the outer edge of the threaded hole and go around the rim of it a bit at a time. Just don't hit the center and strip or damage the threads.

Jeff

[1983Pinin]

Hi Jeff,
Thanks for all of your tips. Regarding the drift for the caliper piston, I may be lucky with this big masonry bit. I don't think it's inside the threaded part. If it works I'll post the bit size.
Regarding the steel to flex brake line connector, it sounds like a flare nut wrench will be the next tool I buy!
Thanks again.
--Peter