Hi Olly if the caliper seal was below par, there would be a good chance that it would let fluid past....but to be fair it could be playing a part in the piston retraction too. Caliper pistons are very finely ground to size; once water gets in around the dust seal there is usually rust pitting after a while. In the past I have used fine wet and dry paper on these with success, but these days I'd just replace the caliper.
If your brakes bleed well enough I'd suggest that the flexible pipe was OK, but cracking the banjo open does release the pressure that could be held on by the master cylinder - but this is most unlikely. A typical symptom of master cylinder failure is that the pedal slowly sinks to the floor when pressure is applied.
If your caliper is the type with the single bolt on the top, and a pin come hinge on the bottom, I've replaced a fair few of these.....usually due to people trying to undo the top bolt completely rather than just slackening it and hinging the thing upwards.
Good luck with it and have a good evening. Cheers John
If your brakes bleed well enough I'd suggest that the flexible pipe was OK, but cracking the banjo open does release the pressure that could be held on by the master cylinder - but this is most unlikely. A typical symptom of master cylinder failure is that the pedal slowly sinks to the floor when pressure is applied.
If your caliper is the type with the single bolt on the top, and a pin come hinge on the bottom, I've replaced a fair few of these.....usually due to people trying to undo the top bolt completely rather than just slackening it and hinging the thing upwards.
Good luck with it and have a good evening. Cheers John