dodgy brakes - V8 auto

[def90]

maybe someone on here can shed some light for me.

Problem - bad brakes - basically on a steep downhill i can have my foot flat to the floor and the wombat won't pull up - neutral or in gear. it feels as though there is just bugger all pressure, pedel feels maybe slightly 'softer' then before.

Vehicle in question - import 87 '90', it originally had a diesel then a 4BD1 was installed (yes i know i'm silly for removing it) and a LT77, last year i put a 3.5 out to 4.3ish (very very mild cam) and a ZF. since putting the v8 auto in my brakes are crap!! it originally had drums in the arse and i put a mid 90's disco rear diff in for disks

i've put new pads in all round, vacuum is 17 foot? mercury (been told 'normal' is 17 to 18 - so not the cam?) , replaced the booster and master cyclinder from V8 110 (booster is smaller then the one that came out and master is slightly larger) replaced the flexi brake lines front and rear about 2 years ago with extended numbers, clamped front and rear independently and brakes are still bad with just one end at a time working, can't find any vacuum leaks, short of replacing all lines next what options are there?

any help would be greatly appreciated as i am hanging for a wheel and its simply dangerous to drive off road at present.

[Strange Rover]

So when you say your foot is flat to the floor do you mean you have pushed the pedal all the way to the floor and yuor still not stopping or is the pedal still high up and you are just pushing as hard as you can and nothing is happening??

If you can push the pedal to the floor your brakes need bleeding.

If the pedal is really hard then something else is wrong...

Sam

[gonfellon]

sounds like brake servo not working or the brake valve that splits the lines if it has dual lines like classic rangie .might be only half working.or booster to small with auto

[def90]

So when you say your foot is flat to the floor do you mean you have pushed the pedal all the way to the floor and yuor still not stopping or is the pedal still high up and you are just pushing as hard as you can and nothing is happening??

If you can push the pedal to the floor your brakes need bleeding.

If the pedal is really hard then something else is wrong...

Sam

brake pedal is nearly all the way to the floor, brakes have been bled a few times with no difference, but the pedal doesn't feel too bad - just feels like when your pads are really shot and doesn't matter how hard you brake it only pulls up slowly or theres bugger all clamping pressure.

[def90]

sounds like brake servo not working or the brake valve that splits the lines if it has dual lines like classic rangie .might be only half working.or booster to small with auto

only single lines, do the auto disco's/rangie's with the ZF have a different booster to fenders or county's or to the manual disco's and rangie's? i'll ask my mechanic if he's looked at the servo. don't know what other boosters are out there? have a mate that did similar conversion on his county and his brakes are fine without changing booster and thats running 38.5's! i'll have a look at my mates rangie booster to see if any different.

thanks for the replys!!!

[gonfellon]

my 86 vogue auto has different size booster than my manual rangies i got, dont no why only that it is,think that spliter line is called brake pressure reducing valve even though not dual it should have something like it, but sound like no boost problem .kind off like been toed and trying to stop with motor not running hard to pull up