Not an SN - but could really use some other brains on this one.

It has hydroboost right?

 

I've changed a lot of brakes, and I had an "off" day installing calipers on my truck. Installed them on opposite sides (which bolted right up), kept bleeding them and it took a day of thinking to realize the bleeders were on the bottom because I installed opposite. It seemed to bleed correctly which threw me off until I realized there had to be trapped air at the top of the calipers. Switched them around and problem solved.

I highly doubt this is your problem but I hope it's something as simple as this. Good luck and keep us posted

 

vacuum leak in the brake booster?

 

maybe its the abs unit. the part that takes the fluid in when it releases the brake. if that valve had a issue then it would go right to the floor without any brake action

 

ABS is supplemental and not used during normal braking operation.

 

i re read his issue and that doesnt make sence...

 

definatly air in the system somewhere. what method are you guys using to bleed the brakes?

 

This is where I'd be checking assuming you know you bled the brakes right, starting in the passenger rear, then driver rear, then passenger front, then driver front, making sure every last bit of air is out of the lines, and making sure the new master is bled as well.

Do some google searches for vacuum smoke tests. They make all the difference in the world

 

did you bleed the master cylinder?

 

The brakes are nice and solid when the cars off cause theres no vac assist...did you physically try turning the wheel with the brakes on engine off?
Is the pushrod in the master properly installed? When you bled the brakes did you have a good solid stream of fluid?

BTW the ride is sweet..

 

Well the only thing I can say if there are no leaks and everything has been installed correctly and the lines are bled....You have a bunk master, not sure where or what kind it is but that's what Id be banking on.

 

check your brake hoses and make sure one isnt swelling up huge. maybe try starting it and loosening lines from top to bottom looking for flow of fluid. also it the adjustment on the booster correct?

 

you say you have tried a 2nd master, have you tried a second booster. I would say a vacuum leak somewhere or the new booster is leaking.

 

A booster problem or vac leak would lead to a very stiff pedal but wouldn't affect the clamping ability of the caliper.

 

I've heard about the abs unit been a pain in the ass to bleed in the newer cars. But I would also think MC...

 

yea i guess i was just thinking that's the only thing that really changes when starting the car, that and maybe the abs