Front brake piston removal advice

[Arbie]

Hi there. Any foccers out there done a front caliper overhaul ? Im going to replace the seals on mine tomorrow and just wondered whats the best way to displace all 4 pistons. Ive worked on sliding calipers before but not opposing pistons. Any nifty little tricks gratefully received.  Cheers.

[Paul]

When I did mine I used an air-line.

I held three pistons in place and fired the fourth one out with compressed air (air line attached to the brake hose).
Replaced the seals put the piston back in and then did the next one.

I don't how hard it is to do if the pistons are seized though.
I suppose it must be possible to undo the 'blue spot' torx type bolt, but I've never tried it.

[Arbie]

Thanks paul. Unfortunately I dont have an airline but cheers anyway.

[Fazerider]

I don't have an airline. I've unmounted the caliper and removed the pads, clamped the pistons on one side then squeezed the brake lever repeatedly until the opposing pads are almost out then wriggled them the last millimeter by hand.
Clean up, replace seals, reinstall, top up brake fluid, bleed then repeat for the other side.

[Jules-C]

If the pistons aren't seized I've done it by pumping them out using the brake lever but you have to do one side of the caliper at a time or you risk the pistons meeting in the middle before they drop out. Make sure you have plenty of new brake fluid you start!

[bandit]

You can use a foot pump & one of those plastic adaptors for blowing up beach balls e.t.c. It's the red one.
 

[Chris]

If they are stuck in and you're removing them to clean them up fully before refitting then if you put a bolt in the brake line hole to block it then you can use a grease gun on the bleed nipple and force grease in to push the pistons out. Had to do it on my rear to get them out, was completely stripping the caliper anyway so didn't matter that it made a bit of a mess. Was easy to clean out though.

Chris

[tweetytek]

You can use a foot pump & one of those plastic adaptors for blowing up beach balls e.t.c. It's the red one.
 

+1  ... I used this connected to one of those car tyre air compressors that work through the cigarette lighter socket. Pushed the pistons out. I used gaffer tape wrapped around pistons I didn't want to move. Just repeat this for each piston