I've replaced all the brake lines and hoses in my Discovery II (2002) (They were all rusted terribly.) My brakes were not 100% good anyway. I suspected the master cylinder was faulty because it took two quick pumps to get a hard pedal and good braking.

So, now with new lines and (stainless steel) hoses and after bleeding the lines...my braking seems worse than ever! Almost no braking at all with a soft pedal!

Is it possible the piston seals in the master cylinder are failing even more now with the new "hard" lines?

Ideas?

 

You need to power bleed the ABS modulator with a suitable diag tool otherwise the pedal will remain spongy. Some claim this can be achieved using the HDC button but IMHO that is not feasible. The ABS modulator needs to be activated to bleed both primary A and B circuits. Refer to the RAVE workshop manual for info.

Also the braking master cylinder may need replacement as it leaks over many years use into the vacuum servo.

 

The HDC method does work also there is a way to wire up a trigger as well

 

I have been tackling a similar brake job problem. I replaced all calipers, rotors, and pads (but not brake lines) and bled my truck's ABS + power bled with the Delphi DS150. Still have an incredibly spongy pedal. Brand new MC and booster is working fine. I have no idea what else to do.

What I can add for your situation is: buy a delphi DS150 (made in the UK not China) or a iLAND device from Atlantic British and you will be able to bleed the ABS and your whole truck with ease.

Hope this helps.

 

AR, I disagree, the HDC button does not activate the shuttle valves or bleed the A+B brake circuits. As for the wiring + a switch via the relay to the motor, again it runs the modulator motor OK but doesn't activate the shuttle valves or bleed the A+B brake circuits.

 

 

Obviously our experiences differ.

 

How does the HDC work if it doesn't activate the shuttle valves?

 

Section 70 of RAVE. The problem using HDC unless on a serious hill is it opens and closes the shuttle valves intermittently even then it's intermittent and it's controlled by the SLABS ECU. On the flat even at the specified speed the SLABS signal controls the shuttle valves in the one position.

However, if those who feel it works for them please carry on but I believe in and use a kosher diag tool for power bleed of the brakes and most importantly the ABS modulator.

 

Not sure how it all works but def better pedal stiffness after downhill with HDC and then re- bleed, a couple of times.