delta_p
OBS Chevrolet, When Silverado Was A Trim
That's great. I think that is a much safer set up. Keep us posted on when it is finished.
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Total waste of time, money, effort, and enthusiasm.One other thing. You should probably think about bleeding this valve.
They make a combination valve bleeding tool that installs in place of the brake brake safety switch during the bleeding process. This will hold the internal piston in place during the bleeding and prevent the piston from shifting over to one side or the other due to air moving through and block the passage to the rear or front which ever direction it moved. The tool is rigid, unlike the switch which can allow the piston to move. The switch gets installed last after the bleeding. the tool looks like this
https://www.amazon.com/Team-Performance-Brake-Proportioning-Bleeder/dp/B07BYVK7SN/ref=sr_1_4?keywords=combination+valve+bleeder+tool&link_code=qs&qid=1580957281&sourceid=Mozilla-search&sr=8-4
The metering valve is open at very low pressure. It closes somewhere ABOVE 15--20 psi, then opens again at higher pressure (~100 psi?) so that the front brakes work.Second. The front brakes get fluid through a metering valve. This valve takes a certain pressure before it opens to the front calipers. To prevent this and make the bleeding easier, they make a tool that will depress depressor on the end of valve and hold the valve open while you bleed. Fluid won't exit at the depressor it just holds the valve internal open. you can use anything available to hold open the valve you don't necessarily need the tool. You could probably make it. it looks like this
https://www.toolsource.com/abs-test...sor-for-abs-brake-systems-j39177-p-61417.html
I'm a little surprised at that.The manual of the '94 though does say the lamp switch can only be reset by fixing the malfunction (assuming this means leak) and applying pedal force to generate at least 450 psi. Or manually i suppose.
The spring could be in the switch assembly, riding on the tapered section of the piston.It doesn't look like the '94 valve above has a spring on that warning piston. If it were me, I'd hold the piston with the brake light tool during bleeding.
The "safety aspect" is that it turns a light on warning you that half the hydraulic system has failed. It doesn't stop the leak. The leak stops when the master cylinder reservoir goes dry, or someone fixes the problem.And it doesn't say the piston blocks the flow like you said as well. It just says the safety aspect is built into the valve. I assume it is in both of the two valves at the front and rear. If you know how it does it, please share. I am always interested in learning this. This particular valve looks like the farrari version of the older style I am used to.
The two hydraulic systems are entirely separate except at the master cylinder, and--depending on your perspective--at the safety switch piston.The safety aspect I was mention is the one that will allow full pressure to the front brakes if the rears fail a leak or full pressure to the rear if the front brakes fail a leak...
...I can't work out how the valve shown from a '94 actually accomplishes this.
Reactions to loss of pressure in one circuit:that's not the only feature in the system performing a response to a loss in pressure.
Not possible. There's nothing in the combo valve that creates pressure; or allows pressure to transfer from one circuit to another. Both the metering valve and the proportioning valve REDUCE pressure to their respective brake cylinders under some conditions. They never increase pressure above what the master cylinder produces.I believe combination valve to also aid in forcing pressure to the opposite circuit.