Outer Limits 4x4 Board

A couple of days ago the brake light came on (hj47 TLC) and the brake pedal has started to become spongy. Today mrs toyotroop said that on her way home this arvo they failed altogether so i took it for a run around the back paddock and its like metal touching metal, ie only just
stopping......... would i be correct in thinking the diaphram in the brake booster is shot? Theres no leakage at any point in the system and i havent lost any fluid. 2 questions i ask.
1. I am mechanicaly minded but was wondering how hard a job is it to
change brake booster (i have a good second hand one here)
2. Is it possible to clean out the hydrolic lines with turps or something.

Thanks all

it sounds like the brake pads a worn out and its taking the brake peadal a long way to work ,
i have seen pads that low that the caliper pistons ready to fall out
1
don't worry about the booster yet, check all the brake pads n shoes for thickness
also check the wheel cyl and calipers for condition/leaks

2 no just flush the system with clean/new brake fluid , use some clear tube [windscreen washer bottle tube is good n cheap from repco ] fit it over the bleed nipple and you can see the clean fluid come threw after it pushes the old crap out ,

when using the tube method put the tube end in a container [a glass container or clear plastic bottle , so you can see whats happening ] with brake fluid in it , enough to have the end of the tube sitting in it you can pump the pedal and bleed the system on your own and not get air in the system

also does the pedal get hard /get better after a few pumps and hold pressure , if it does not there is a good chance the mater cylinder is faulty


check pedal /master cyl first ,fine or fix

then brake pads ,fine or fix

then do brake fluid flush , if not confident it is best give it to somone who knows what there doing

That sounds spot on to what i'd do if the pedal is creeping down under pressure it's master cyl or it's pumping fluid into somewhere it shouldn't be