Caliper pistons. Inequality aftr rebuild. Significant?

[chrishawley]

Not sure there's an answer to this of if it's even a question. Here goes.....

Girling16 calipers rebuilt. On testing with a bit of compressed air, the pistons don't respond equally. One side moves very readily while the other side requires more sustained pressure to move. But both sides 'rock' on the seal quite nicely within what woud be the operating range of movemnt.

How much inequality is ok? Or is it irrelevant in the context of the pressures that will actually be applied by the hydraulics, in use?

I can see that's not quite a question. But any insights would be appreciated.

 

[Colin Lindsay]

It may be down to the design of the caliper but I don't think it will make any difference in use unless there's really significant sticking by one piston. One piston may move more quickly but when it reaches the disc it will stop and the other will then move out until the pressure equalises on both sides against the disc. With firm pressure on the pedal and a well bled system any imbalance should be minimal. Keep an eye on the pads though and any sign of disproportionate wear may indicate that one piston is failing to move properly.

[johny]

How much holding (finger?) pressure do you have apply to the easier piston to hold it back while the other moves?

[chrishawley]

29 minutes ago, johny said:

How much holding (finger?) pressure do you have apply to the easier piston to hold it back while the other moves?

Pretty much maximum grip between two fingers and thumb.

[johny]

Take it the seals/pistons were all lubricated with fluid on installation?

[Clive]

I would be popping the pistons and seals out, maybe swapping seals side to side. And check piston diameters, especially if new. 

Hope you are not getting fingers between the pistons when using compressed air on/in the caliper😬