4evascoob

yes it does , once cleared the vacuum with it off it goes solid. Start up and it sinks. If you pump it a few times it stiffens then sinks again.

TECHNOPUG

iTrader: (1)

Servo issue?

4evascoob

I thought it had the other effect and made pedal still ? Seems good vacuum and can’t hear any leaks , and was all normal when I blanked of the mc it’s all very odd.

TECHNOPUG

iTrader: (1)

Maybe try and find a Nissan Navarra forum if there is something specific to how they are plumbed? It's a hydraulic system and if it's full of fluid with no leaks, I can't see how the pedal can drop to the floor? Did you say you have checked the rear drums/cylinders?

4evascoob

I did have a look and it’s a common asked issue with as many answers ! lol , I may try and isolate the rear and then the front with the plugs off the module and see if I can at least tell if the issue is fr or rr, a common one is that the abs should be cycled and follow the diagnostic tool but I’ve bled loads of trucks and cars , buggy’s , quads etc and never had an issue. All this happened before the system was ever opened so makes me think it’s something that’s worn or broke. Me changing mc has definitely not helped ! I’ll take to garage and see what they say or so and will report back.

nicam49

OP's probably gone offline now, but anyway, perhaps by clamping each brake hose assuming they're unbraided ones, would help eliminating parts of the circuit. 🤔

4evascoob

That’s an idea ! All normal hoses.

stamina_daddy

iTrader: (3)

Faulty new master cylinder?
I fitted a supposedly brand new one (blueprint).
Pedal still went straight to the floor no matter how many times I bled it.
Took to garage and they bought another master cylinder and bingo worked straight away.

Vxr2010

Good it's finally sorted ,one item being returned then , im surprised a new unit failed , but at least it's sorted now 👍

stockcar

that's someone else??

Vxr2010

Oh lol 😂👍

4evascoob

Haha I thought that. So dropped it at garage today. Will report , I tested new mc with plugs and it was fine. No pedal drop. I’m wondering if it’s air in module as abs hasn’t been activated as it was showing abs light because of another issue. Pulled in from mc change.

4evascoob

So garage has bled system with diagnostics to activate and purge abs. He said a bit of air came out but not a lot. He reckons it’s the servo ?? I thought it made pedal hard but he said he has known it before. I’ve ordered one and see what happens.

4evascoob

So after doing the master cylinder , servo , garage to diagnostic bleed abs it was …….. a stuck fr right caliper piston. Saw a little post about clamping each individual hose. Worked from fr to rr and clamped each one and pedal still went to floor. Clamped the last one fr drivers and pedal was solid after about an inch of travel. One piston froze solid and sliders stuck. Disassembled and cleaned re greased and all working a charm ! Wish I’d found that post sooner. !!

stockcar

hope you used the correct "red" rubber grease as the likes of copper slip attacks the seals and you will end up with seized sliders (again)

4evascoob

thanks for letting me know as that’s exactly what I used ( copper grease ) thought it was all things brakes ! lol , as it turns out I’ve ordered another caliper as I wasn’t confident I’d put back the dust covers correctly over the pistons and one piston that was stuck had a ring of rust around it that didn’t really come off despite wet and dry so it might size again. Full kit for rebuild is £48 and new caliper £80 ! No brainier really. Just glad I found the culprit.