hilux brake problem... please help!!!

[Roctoy]

ok.

i've put the bigger motor in my 84 extra cab yn 65, the engineer said i have to upgrade to vented disc brakes.
so i have done that used dba 151 discs, all bolted on fine, bought some calipers off OL, 1996 model hilux ones, the pads are faily new, everything bolted up first go, but for the last month I HAVE NOT HAD BRAKES.

Every time i apply the brakes the pedal goes to the floor as if there is a heap of air in the system, there is not. I repeat, there is no air in the lines, they have now been bled about 20 times by myself and 2 reputable mechanics workshops. I have put a kit through the calipers and still get this problem.
If i jump on the brakes hard, the rear wheels lock up and the fronts do fark all, then second pump, I HAVE FULL BRAKES. Go figure.

Has anyone done this brake conversion and is the standard hilux master cylinder up to the task?

I have had all sorts of advice so far and now i'm looking at replacing the shims behind the pads baecause they are slightly bent...

It is frustrating the shyte out of me, as the brakes were working fine before i changed the calipers.
Less than a month before a trip to Cape York i need to get the problem sorted.

Any advice hould be appreciated.
Cheers Chris

[MacroP]

You now may not have a big enough master cylinder. Are new calipers from an actual Hilux ute or perhaps a Surf or V6 forerunner which had the larger 45mm pistons(vs 35mm) and master cylinder.

[Roctoy]

the calipers are off a 96 hilux single cab petrol.

Chris

[4sum4]

Don`t think you will need a bigger master cylinder only if you need to pump the peddal a few times after the first time.

and the problem could be Water in the fluid

[ozrunner]

Your MC bore size needs to be a minimum of 15/16" so check your current size and replace it if its smaller and you will have front brakes again.

As you have also opened the front lines you will need to bleed the rear LSPV at its bleeder valve as there is probably air in this line from the front , which will not be helping your braking.

JD

[Roctoy]

thanks all for your advice but the problem turned out to be much, MUCH! simpler.

The steel shims that sit in between the pads and the pistons had a slight bow to them, this was the only thing that the brake guy that i buy all my stuff from could find wrong with the brakes. i took them out and the problem went away. I will put new ones in today.

If your in Sydney and need brake stuff here's a wrap for Peter.

Weldon Brake & Clutch
Shop 4, Cnr Kareena Rd & The Boulevarde,
Miranda 2228
ph 9524 0903

Cheers Chris