VT Brake Upgrade Problems

[GTP 85]

I have just fitted a complete VT Brake upgrade to my VS and i am having a few problems.

What i have fitted is...
VT Twin piston calipers
VT rotors
VT Fast fill master cylinder
VT Booster
New brake lines

Since fitting i havent been able to get proper pedal pressure.
The pedal is still spongy after bleeding the brakes about 4 times now.
The weird thing is that when you turn the car on and get vacum assistance from the booster the pedal go's really soft and go's to the floor.

I thought this was a problem with the booster and master that i got so i replaced them with the original vs booster and master which did the same thing.

Since then i have put the vt booster back on with anouther vt master and im still having the same problem.

Tried driving the car with the booster disconected and the brakes have almost no effect. Tried with booster connected and its worse.

Is there a special way of bleeding the brakes on an abs equiped car?

What am i doing wrong?

Is there anything else you have to change when doing the upgrade?

[Surfwagon]

Just posted an answer that may help on SC forum.

[VrWagz1]

Does the booster hold vacume, maybe thinking busted vacume hose leak. Souns fine what you've done

[cxcxcxvcvcvc]

Hey mate scored this from another site, (professional brake shop ect) hope it helps!

(When trouble shooting a soft pedal, clamp all hoses, taking the clamps off one at a time until you find where the softness is coming from. If you still have a problem with all lines clamped, then the master cylinder is the cause. If the pedal goes hard, it is fine. Sometimes the hose itself can be swelling.)

also

A reaction disc is a small rubber disc which lives under the head of the booster output push rod. If this is lost, the brakes will be nearly uncontrollable with stopping proportional to pedal position, not pedal effort, sending you through the windscreen at the lightest touch.

and

. With all modified systems, check everything for clearance, through all suspension travel and lock to lock, particularly brake hoses and calipers versus cross members and sway bars etc. on lock.

[VrWagz1]

With all modified systems, check everything for clearance, through all suspension travel and lock to lock, particularly brake hoses and calipers versus cross members and sway bars etc. on lock.

+1 for that, i found the hoses i got with my calipers looked fine and installed fine, but on full lock they kinked an even stretch a little bit whics is a little less than ideal.