The Official 356Talk Forum

I had taken my front and rear brake calipers apart to rebuild them for my 356C. I had an extremely hard time getting the pistons out but managed to blow them out eventually. I got the rebuilt kits but having a difficult time getting the pistons to go in. There's a "pin into sieve" in the back of the piston that seems to prevent the pistons to go into the caliper. Does anyone know how to reassemble them.
Thanks
Alan 8)

If you wish to retain the assembly that grabs the pin then put the pistons in with a big C-clamp.
If you don't want to retain the assembly that grabs the pin then put the pistons in with a lesser sized C-clamp or maybe you hands and fingers.
There have been discussions with much more detail about this in this talk list.
Make sure you get the rotational orientation of the pistons set per the service manual.

Do not leave out that assembly that grabs the pin! No one here has put more R&D into this system than the manufacturer back in the day. It's there for a reason! Some have left it out and reportedly haven't had a problem, but it is NOT recommended. Leave it in and let it do its job.

Put a small block of wood over the piston then use a c-clamp as mentioned. This will force it onto the pin at the back of the caliper. Make sure it goes in straight.

And now to answer your next question.
"I've rebuilt my calipers and bled them twenty-five times and still don't have a good pedal!"
You will need to "exercise" the pistons. Once the brakes have been bled, pull one brake pad at a time, put in an old thin one and push the piston out; then back in; then out, etc; at least three times. You will notice an improvement with each piston. The square-cross-section O-ring needs to be seated properly, or it will keep pulling the piston back. The "pin-grabber" helps the piston to not get retracted too much upon brake release, but it can't work miracles. Yes, I use it in my race cars also.

+1 Vic,

Dick

I am rebuilding my calipers now, too. Lots more tips and photos in the following tech article, plus the two listed threads:

https://porsche356registry.org/article/153

viewtopic.php?f=1&t=33087

viewtopic.php?f=1&t=32880