Sometimes the pistons on new calipers retract a fair way which will always need more pedal movement to push them back out before theres any braking affect, which can give the impression there's air in the system although what you described sounded like excessive pedal movement. In my motorbike days sometimes after doing caliper overhauls the front brake lever would come back to the handlebar so we would leave an elastic band round the front brake lever/handlebar overnight to get the 'feel' back. As SF said try the power bleed. My Foxwell NT530 has a power bleed option but I haven't needed to use it as when I did mine, like you, I clamped the hoses so the system didn't drain down, good luck.
 
My master cylinder seals had split... theres no leaking fluid, just very little pressure as the fluid by-passed the seal.
 

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Looking back.... I was looking at the clutch master, but it equally applies to the brakes...☺️

If I remember correctly, I replaced my master brake cylinder because I stupidly picked up a bottle of ATF, instead of DOT4, and fecked the seals in it, because the o rings expanded, and caused the brakes to lock on..... Only way I got home was to loosen off the brake lines and use the handbrake and gears to slow down....
 
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Looking back.... I was looking at the clutch master, but it equally applies to the brakes...☺️

If I remember correctly, I replaced my master brake cylinder because I stupidly picked up a bottle of ATF, instead of DOT4, and fecked the seals in it, because the o rings expanded, and caused the brakes to lock on..... Only way I got home was to loosen off the brake lines and use the handbrake and gears to slow down....
Oops!
 
I have a bit of a follow up on this one.
BRITPART SAVES THE DAY!
Who would of thought anyone would ever say that, also goes to show there are a lot worse parts out there.
Bought some new Britpart specials, fitted them this evening, bleed them once and all good.
So in conclusion the first lot of calipers bleed fluid through ok but actually did nothing else. On the upside, if there is one, atleast they failed straight away and not on the road, bit worrying all the same.
 
I have a bit of a follow up on this one.
BRITPART SAVES THE DAY!
Who would of thought anyone would ever say that, also goes to show there are a lot worse parts out there.
Bought some new Britpart specials, fitted them this evening, bleed them once and all good.
So in conclusion the first lot of calipers bleed fluid through ok but actually did nothing else. On the upside, if there is one, atleast they failed straight away and not on the road, bit worrying all the same.
Had Britpart callipers on back of my 90 (Disco axle) for five years and still fine
 

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