How exactly does the button function on the metering valve work for bleeding? I understand the normal operating function. It is supposed to hold the pressure to the front brakes until the rear starts. At ~30 psi the complete spool valve assembly moves out allowing pressure to the front brakes. Left side of first image. Spool valve assembly Valve body plug: When the valve is closed, the rubber sealing washer of the spool assembly is pressed on the valve body plug. and blocking off fluid flow. Shown in the right part of first image. Now what is pressing the stem/button, like the purple arrow, going to do here? I can't wrap my head around it. The stem will move relative from the other parts of the spool assembly. On the inside it will push against the rubber sealing washer and perhaps stretch it a bit, but as I can see it, the outer edge of the rubber sealing washer will still be pressed on the valve body plug and will still be blocking the flow. I've used the rebuild kit of musclecarresearch.com so everything should move freely, but pressing the button didn't work (or perhaps I should have used way more force) I have used a vacuum bleeder a while back, but at the moment only my rear brakes are working; the front not (so much). I'll be bleeding the old fashion way today with a helper on the brake pedal, but this was still nagging. (Brake pedal is firm though)
Well, we performed the bleeding today without pressing the button. Way better, now it actually is breaking with the front, but we're not there yet. Right rear easily blocks, so the front isn't breaking enough yet. Did notice "sweating" connections, so tightened them some more, other than that no leaks. I did bench bleed the new master cylinder, but never did that before, so no clue if I did it right. We'll continue another day. But pressing the button doesn't seem to be necessary.
