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Jerry Newton
Jerry Newton, Chevy Technician
Category: Chevy
Satisfied Customers: 4508
Experience:  ASE Master Technician, L1, Master GM Technician. Over 20 years of bumper to bumper GM experience.
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I have a 92-Silverado {350, automatic, power brakes} with a

Customer Question

Hello, I have a 92-Silverado {350 CID, automatic, power brakes} with a drum RWAL-system in the rear and disc brake system in the front. The hydraulic tubing to the back wheels was leaking and consequently replaced. In the process of bleeding the rear-wheels the reservoir went empty (front compartment only, I believe this reserved fluid is for the rear brakes only). The current symptom is.....pedal fairly solid with the truck not running, with the truck running...the pedal goes easily down to the floor & the diagnostic brake light comes on at the dash towards the end of travel. I have read several descriptions online while trying to do my homework here. But because of my inexperience, lack of positive indicators up-till now I'm looking for simpler solution. One of the SOP's describes a "metering rod that needs to be depressed, on the combination valve" do you know what they would be talking about? To your opinion what is the best way to make sure all air is removed?? What does the [TECH 1 scan tool] do for the bleeding process? Also could you call me???
Submitted: 1 year ago.
Category: Chevy
Expert:  Jerry Newton replied 1 year ago.

The combination/metering valve is directly below the master cylinder, and when you have an imbalance of hydraulic pressure (like a bro***** *****ne), this metering valve will move to one side, and the red brake light comes on.

The valve has a tendency to stick in this position. If you look at it, you'll see a rubber cap on the end of the combination valve. Remove this rubber cap and see if you can use a tool to push in the middle of that little button. When the metering valve is centered where it belongs, the little pin inside that button should be flush. If it's sticking out or is too far depressed, sometimes some careful tapping with a small hammer will free it up, or at worst, you will need to replace the combination valve.

I'm sorry I cannot talk on the phone to you, the shop is very loud and I can't carry on a useful conversation.