chris walrod

Stick a wide enough piece of wood in the throat of the caliper, and with shop air, see if all four of the pistons will extend to the wood. Watch your fingers, of course

If this works ok, then your calipers are ok.

Keep everything really reall clean upon reassembly -- its important! Wash your hands twice before reassembly.

GRUWEZ

Hi Chris,
Thanks for the tip. Actually I tried that. What happened is that the inner pistons (the ones adjacent to the hole where I apply shop air) get pushed out first. Those pistons push the block of wood against the outer pistons before the outer ones get a chance to pop out. Mind you, if I block the inner pistons in place, the outer ones do pop out. Just to be 100% clear, it is the inner side of my rotors that are very rusted.

Meanwhile I have been browsing through thousands of Rennlist posts until I found this one:
https://rennlist.com/forums/964-foru...ion-where.html

I managed to remove one positioning plate and there is indeed quite a bit of corrosion behind it. You can see it in the caliper photo I posted earlier. My best bet is probably to thoroughly clean all four calipers and then take it from there.

In any event, thanks for the tips, and... feel free to chime in if you have any more tips. I am a newbie at this and all help is very much appreciated!

Regards,
Rik

graeme36s

My 964 3.6 turbo used to warp the discs. Similar problem, new calipers problem solved. No rime or reason but it solved the headache.

budge96

Gruez.. have you tried bleeding both sides of the caliper? Sounds as though one side only is excerting
pressure while the other is not...
Would appear that inside would get the most pressure but possibly I'm wrong,you do have dual bleeders...it's a shot ! Bert

GRUWEZ

Yes, bleeding both sides of all four calipers was done by the dealership. I spent some more time in the garage today. Both front calipers are off and on the bench for rebuilding.

I still need to get the rear calipers off. Unfortunately, the flare nut (the one that attaches the steel brake line to the rubber brake hose) probably has not been touched since the car left the factory. It is quite awkward to reach. It does not budge with a regular 11mm wrench, so I have ordered an 11mm flare nut wrench. Should have it next Wednesday. Meanwhile, the nut is getting soaked in WD-40. Perhaps that will make a job a bit easier as well.

Regards,
Rik