I only have one on the rear brakes. front seems to be level with master cylinder. I think I might be ok.

 

Need one on the fronts as well! That may very well fix your issue. Also when bench bleeding MC the floating piston can be forced off center. That will be apparent when you hook up the brake trouble indicator.

 

Another thing to check is the pin between the booster and master cylinder .
Make sure there isn't excessive clearance in there as it will give you a low pedal .
Not enough clearance will give you brakes that will drag , make sure it's correct or you will never get your brakes right .

 

If you havent started the engine how can you tell you have weak brakes? I have never had good luck bleeding a power brake system unless I had the engine running to energize the booster and without the booster energized I dont know how you can really tell how the pedal feels.

 

See post #5

 

Do you mean the "depth correction plug"? The piece you slide into MC when bolting on to power brakes? It's in.

 

You get a better feel of the pedal with the motor off. It should be rock solid on the first press, and a bit firmer with the next.

 

Never heard of a depth correction plug being used ?
There will be an adjustable pin on the master cylinder side of the booster , this MUST be adjusted to suit the master cylinder used .
Most m/cyls have a circlip retaining the pistons into the bore , if so you need to adjust the pin so there is close to zero clearance between the pin and master cylinder piston .
Some m/cyl's also require a slight preload on the piston , so you will need to find out what your willwood master cyl requires .

 

What front calipers are you using? From what model were they original to?

 

Agreed. I check power brake systems without vacuum when setting them up. Then I check with vacuum. Make NO MISTAKE: Vacuum assist is the luxury, the hydraulic system must be right or people can get hurt. As Axe suggested, pedal will feel different if engine is started with foot on brake. Of course, this assumes that system vacuum bled off prior to this.
Make certain that RPVs are for disk brakes. Drums require a higher residual pressure.

 

I'm using gm metric calipers 78-88 from speedway motors.

1978-88 Replacement GM Midsize Metric Calipers - Speedway Motors, America's Oldest Speed Shop


I also have a 2 lb. rpv on rear brake line.

Depth correction plug here. Watch 1:36 into video.

 

Not all 78-88 G body calipers are the same, around 1980 or so they were changed to quick take up style with a different corresponding master cylinder. QTU calipers retract more for less drag and use a master cylinder designed to make up the difference. Google it and you will find lots of information on them.

 

Like Ax said you need a RPV in the front brake line also. Without it you are going to have pedal travel issues.

 

I have another 2 psi RPV in the parts box. I'll throw it on tonight and see what happens...

 

Any progress?