2000 Discovery TD5 - brakes won't bleed

Just had a call from a friend who has just replaced a front caliper on his 2000 TD5 (he was setting out to do both but did the first one and ran into this problem) and can't get any fluid through the system. With the nipple open the pedal goes to the floor but no fluid comes out. He's even tried removing the caliper and no fluid even comes out of the brake hose ! Yes he's topped the reservoir up.
Does the system need plugging into Hawkeye or similar to bleed these brakes or can it be done conventionally ? If it doesn't need Hawkeye, does this sound like the M/C is kaput or is it likely to be an ABS problem ? He called me because I have a RR Vogue and have just replaced brake lines and calipers etc - had none of these problems though.

It's certainly not an ABS issue, tell him to undo the flexi hose from the pipe at the chassis and see there cos it might be a restriction in that flexible side or something... bleeding with tester is needed only if the modulator was changed

did he clamp the flexi or let the fluid run, if theres air further up it might need bleeding at the master then abs block then caliper

sierrafery said:

It's certainly not an ABS issue, tell him to undo the flexi hose from the pipe at the chassis and see there cos it might be a restriction in that flexible side or something... bleeding with tester is needd only if the modulator was changed

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+1
It could well be a collapsed flexible pipe. Especially if he used a clamp to seal the pipe when he removed the caliper.

Thanks for the replies, he's at his wits end with it !
Yes, he used a clamp, so there shouldn't have been air further up in the system, but I take the point about crushing the flexi pipe. But if a flexi had caved in and blocked the flow to the caliper, surely the pedal wouldn't be able to go to the floor ?
When he's (slowly) pumping the pedal to bleed fluid through, the pedal goes to the floor, but nothing is coming out of the bleed nipple. With the bleed nipple open he's describing the pedal travel as smooth light pressure for the first bit of travel, then a gap where the pedal just drops, then pressure again but juddery. The fluid level in the reservoir doesn't seem to drop.
He's just told me the reason for changing the calipers was they were "pressurising". He says he was getting brake binding on the fronts (only) which could only be relieved by opening the bleed nipples (then fluid would squirt out under pressure and the pistons release). The pistons moved in and out smoothly, but seemed to be getting pressurised somehow in normal use - over 10 miles or so of normal driving.

It seems that the master cylinder is fubar then or there's a fluid leak somewhere

I think that is where we'll start. Will it need a diagnostics bleed after changing the M/C ?

Would be good but not compulsory cos normally there should not get air into the ''active" circuit

He's getting it trailered to his local independent to see if they can fix it - it'll be interesting to see what the verdict is, I'll try to remember to post it here for future reference.

Was messing with the Hawkeye the other day it has a brake bleeding programme on it.

Is the fluid reservoir cap off while he's trying to bleed the brakes ?
It's not unknown for the vent hole in the cap to become blocked & cause problems such as long brake pedals or poor bleeding.
If the cap wasn't fitted during bleeding, it obviously can't be the cause !

has the master cylinder or booster already been changed. You could get similar symptoms if the booster output rod is holding the mastercylnder pistons too far forwards

So its up and running again ! Yes, it was bled with the reservoir cap off so that wasn't it. It was the master cylinder - replaced with a new LR one yesterday and all is fine again.Thanks for the suggestions and encouragement !

I've just started looking for a D2 TD5 myself now to replace my FL1. There seems to be a lot about (though not on here) at wildly varying prices so I don't doubt I'm going to have an interesting time finding one

I had trouble bleeding my brakes and bit the bullet and bought a new master cylinder, as well as a lynx diagnostic unit for power bleeding. Worked fine after that.

Hi I'm having the same difficulty tried a vacuum bleed and good old fashioned method one in car and one out neither worked my oil looks black and dirty in the reservoir I have recently do a reverse clutch slave bleed (could of caused oil to look dirty) then the other day my breaks locked up on me I pulled the vacuum hose and put it back on and they released enough to drive home but since my breaks have been spongy. Now when I press the pedal there what seems to be a bumb half way through the movement and hardley any pressure could the be master or servo