Rotating caliper pistons

[kevinhall]

Hi, just had my calipers refurbished and come to refit them and the pistons are not rotated correctly for the backing plates. Is it possible to rotate them in situ (doesn't seem to be easily) or do the pistons need to be removed and reseated correctly? If the latter, how do you remove the pistons - van off the road so no hydraulics connected.

Ta muchly for any advice.

 

[Moseley]

Are they protruding enough to get some mole grips on them? If so, wrap a rag around the piston to avoid damage, and grab it and twist it clockwise.

 

[gvee]

I bought a new pair, one of them was misaligned like this. I was able to tap it round when I had it on the bench using a hammer and screwdriver. Gently does it and job's a good'un!

 

[kevinhall]

Cheers both. Not enough sticking out for moleys unfortunately. I've tried a screwdriver and hammer on one and not playing ball but I'll try another. Every job on this van takes 10 times as long as it should :evil:

 

[jonboylaw]

Try blowing some compressed air in to push the piston out a little. Use a dry line and put something solid over the piston to stop it shooting across the workshop...


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[RePhil]

You can buy a proper tool which fits partly inside the piston & engages between the notched out section you are trying to align.

I know it's not the right tool for the job but:
I once used a flat bastard file to do this. Insert the end of the file into the bottom of the piston & gently position the flat adge of the file against the notch. (Imagine a very large spoon resting in a tea cup, which has a chip in it). Rotate the file, like the hands on a clock, & you should be able to rotate the piston.
Be careful, files are very brittle so don't bend it.

As has been said, pushing them out with comp air will move them. Wedge a block of wood in there first.

Phil.

 

[kevinhall]

Thanks for the suggestions. A job for Friday and will report back on progress!

 

[kevinhall]

So, searched around and ratwell showed an alignment tool but very pricey. So I had a crack at making something:



Fitted snugly into the piston and enabled me to pop a ratchet spanner on, the metal piece caught in the piston groove and gently rotated the piston:



Two of the pistons wouldn't move so clamped one piston, popped in a bit of old brake line, connected to a bike pump and popped the piston out:



Could then gently rotate it and push back in.

Now all lined up and pads in. Thanks for all the info and ideas.