hi im having trouble with my brake setup on my 92 hilux.
i have 7" dual diaphram booster. 1" bore master. standard front brakes, single piston ford rear calipers and rotors.
everything brand new, pads, reco calipers, disc etc... new stainless hardlines, braided lines.. no leaks what so ever

its an underdash 90 degree setup, custom made pedal to the 4-1 ratio.
now the problem is it stops but slowly i cannot get wheels to lock up or even just bang dead stop... it just slows to a stop under full brake pressure...

the setup i have either takes a 33mm or 39mm spacer between the booster pin and master piston.. i have tried both nothing really changes except the the longer one the pedal is really harder and the brakes are constantly on slightly. we have bled and bled and bled the system i reckon 20+ times. it has a valve block that seems non adjustable..

has 13" of vaccum @ idle. 1500rpm+ it has 17-19"
the booster needs 16" to work properly but it doesnt change pressure even while revving.

hope someone could help.. pm me if you like

cheers

 

I have gtr 4 piston and 300mm disc to go on but they dont fit under 15" steel rims which i need for engineers certificate.. So my plan was to fit these when i get my billets... The brakes worked 10x better when the truck was standard

 

your also loosing pressure through the pedal. the pedal instead of 1 pivot point like the standard toyota set up. you now have a couple more pivot points im assuming since its the aftermarket brake master and booster. and you now have a huge v8 motor inside(not sure if its aluminum block n head not a chevy guy) just throwing those simple ideas out there. wen i went from 17 inch rims to 20inch rims with just a master hooked up i could feel the difference of trying to stop. good luck!

 

Did you put a adjustable proportioning valve in the mix,if not there's your problem. A must to have the correct balance front to rear on your braking & rear disks add to this!
I have big rotors @ the front & a 4-piston caliper & the larger master & booster & 11.32 '' rotors @ the rear. All works just fine!

 

can you check what pressure is being applied in the system?

i have a wilwood dual underdash manual m/c, all stainless hardlines etc. also front and rear brakes are from a 87 toyota supra turbo.

i've noticed that it seems like they don't build pressure like it should. i know i still need to do some bleeding as the pedal is soft after sitting over night. i've read that the wilwood stuff is a pain in the ass to bleed though lol

 

yeah i bench bleed mine.

wilwood says to jack up one side and bleed them, then jack up the other and bleed. i haven't done that part yet lol

 

No on bench, traditional method!

 

alright we have lifted the inlet for 10th time checked everything resealed everything bolted back down.. changed from heater hose to proper vacuum hose. re bled each caliper, starting furtherest corner first 10 big hard pumps then bleed done each caliper 10 times... total 40 bleeds this is how much fluid came out
rear pass


then rear drivers


then front drivers


then front pass


40 bleeds lucky to be 250ml of fluid... i think theres a fluid transfer problem.. any advice where to go from here?? proportioning valve?

 

It's farthest first,rear drivers side,rear passenger,front passenger,driver. Through I don't think this is the problem!
Pump a few times with screw closed,hold down & open screw,close screw, release pedal.
And you are holding the pedal down on last pump & closing the bleed screw?
I always start with the hose under clean fluid,as you can see any air bubbles,& you can not pull air back into the line, when no more bubbles are seen from the wheel your on ,move to the next!

 

yes thats how we do it, tho i dont think the bleeding is the issue i think its part failure somehwere... what id give for someone on one forum to go "yeah its this part thats stuff just replace that and it will be sweet" lol but just seems no one knows and im going around in circles haha