Chevy brakes

I put a new brake master cylinder on and bled the brakes (1995 chevy k1500 w/t) but the brake warning light is still on. Is there a trick to getting it reset?

Reply to
Ringer
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Yes - there is a "balance switch" that needs to be centered. it will be tripped either to the front or the back. you need to try bleeding the front brake with very light pressure, with someone watching the light. As soon as the light goes out you need to shut the bleeder. If that doesn't work, you need to bleed the rears the same way..

You don't need to take my word for it ----from

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Use a test light by attaching a clip to a positive contact on the vehicle and touch the point of the tester to the electrical connection of the combination valve. If the the light does not come on, the valve system is operating correctly and no further testing is required. If the light does come on, this indicates that the pressure differential valve is stuck in the front or rear position. Bleed the brake system to determine if the front or rear lines are blocked off. Set up one front wheel and one rear wheel for bleeding at the same time. Crack both bleeder screws and gently pump the pedal a few times. The blocked side will trickle fluid out when the bleeder screw is cracked and the pedal pressed. An unblocked line will squirt fluid out the bleeder. The lines that are clear must be left open and the blocked lines should have the bleeder screws tight to cause pressure to build up on that side. Be sure to use the standard bleeding procedures to prevent air from entering the system. Slowly press the pedal with steady pressure a number of times until the light goes out; this will center the differential valve. You may also hear a pop come from the proportioning valve. This is the metering valve returning to its equalized position. When the light goes out, close the bleeder screw.

Reply to
clare

Still have light on. I noticed that when the brakes are pushed you can see the fluid in the large chamber of master cylinder surging. Front cylinder doesn't. Is that normal? The cover has 2 bellows but they don't fit the front chamber. I looked at the old cover and it was flat all the way across (no bellows). Could wrong cover have been put on new cylinder because it doesn't seem like an airtight seal.

Reply to
Ringer

The bellows or lack tereof won't affect the action of the brakes - The bellows is there to keep moisture-laden air from contacting the hygroscopic brake fluid to keep it from absorbing water.

Have you "bench bled" the master? You need to get all the air out of the master before attempting to bleed lines and center the valve.

Reply to
clare

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