ABS AND BRAKE LIGHT STAYS ON ALL THE TIME

red98

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Nice Blazer. To add to what 618 syndicate said, how is the brake peddle hight? You may need to adjust the back brakes if all else is good. Another clue is, how far can you press down the EMG brake peddle. If its more than about 1/2 way then you need to adjust the back brakes. I just did mine this week. Now my EMG brake peddle only goes down about 1/4 of the way before it starts getting hard. This also helps to pull up the regular brake peddle too, and can make it feel firmer.
How should the brake pedal height be? Mine is like an inch higher than my gas pedal, is that "normal?" My E-brake is disabled so the other advice doesn't work for my rig.
 

kennythewelder

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How should the brake pedal height be? Mine is like an inch higher than my gas pedal, is that "normal?" My E-brake is disabled so the other advice doesn't work for my rig.
Lets say that the total travel of the brake peddle is 8 inches. ( Just a random number, it may be more or less) mine starts grabbing around 2 inches or so. At 3 inches this is where most of my braking is done and at 3-1/2 inches my brakes are locking up. Again these are random numbers. But all in all, im locking up my brakes at a little less than 1/2 way down to the floor. If you have to go passed the 1/2 way point to get your brakes to work, then there is an issue that need to be looked at. A leak, rear brakes that need adjustment what ever. Also you say its pulling to one side when the brakes are applied, then that caliber has issues, or the brake hoses have issues.
 

Pinger

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Lets say that the total travel of the brake peddle is 8 inches. ( Just a random number, it may be more or less) mine starts grabbing around 2 inches or so. At 3 inches this is where most of my braking is done and at 3-1/2 inches my brakes are locking up. Again these are random numbers. But all in all, im locking up my brakes at a little less than 1/2 way down to the floor. If you have to go passed the 1/2 way point to get your brakes to work, then there is an issue that need to be looked at. A leak, rear brakes that need adjustment what ever. Also you say its pulling to one side when the brakes are applied, then that caliber has issues, or the brake hoses have issues.

Not disputing your description - especially the first 2'' of free travel - but the GM manual has the exact figures for permitted travel. It also insists on precise measures of applied force though - which makes it only slightly more useful than useless. Still, there are precise numbers there if anyone wants them.
 

kennythewelder

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Not disputing your description - especially the first 2'' of free travel - but the GM manual has the exact figures for permitted travel. It also insists on precise measures of applied force though - which makes it only slightly more useful than useless. Still, there are precise numbers there if anyone wants them.
Good info. Like Ii said, my post is only an estimation,and thats just by memory. I didnt take any real measurements.
 

bowtie-72

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Going out on a limb here. In my personal experience, I would suspect one or both of your rear wheel cylinders are bad. Did you pull the rear drums to see if one or both are wet? These are frequently froze up internally and even if they aren’t leaking they will cause an uneven application of rear brake and will cause your light to come on. I would check both by squeezing the ends with your thumb and forefinger and see if you can move the inside of the cylinder back and forth just a bit. If you can’t then one or both sides of the cylinder are bad and will have to be replaced. Do yourself a favor and if you replace one side just go ahead and replace the other side. Every time I try to cheap out and just do one side I end up replacing the other side soon afterwards and have to bleed the system again. They are cheap enough from Rockauto. Side note, you need that ebrake to function to keep the rear brakes adjusted. When you get that all installed it will work fine. Just get into the habit of using the ebrake every once in a while.
 

Pinger

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thanks i will check them this weekend i did pull thhe drums a few months ago and they were completely dry. i will most likely just change both wheel cylinders when i buy the emergency brake cables. i appreciate everyone's advice....

Leaked fluid can hide behind the external boot and the pistons can (and do!) seize solid.
 

HotWheelsBurban

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I had the master cylinder replaced on my Burb several years ago, and the guy that did the work also replaced the wheel cylinders. A couple years later I replaced the calipers and front brake hoses. Truck stops well, but ABS light is on. Found out the wiring harness on one of them is damaged. Have new parts and will be replacing them soon.
To add to what others have said, the brakes are adjusted on the Duo Servo style ( what the SUV 400s have) by braking while in reverse. IF the adjusters are free and lubricated. All that linkage in there, has to be clean and lubed to work properly. There's a special high temperature brake specific lubricant that any parts store should have.
Apologies if this sounds like I'm talking down to you; not sure what you know and don't know. Good luck!
 

Jim M

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Hi people. I'm having the same problem with my 1992 Silverado C1500. Brake pedal is nice and firm, Emergency pedal goes about 1/4" then gets firm. No leaks that I can see. MC has no leaks, not loosing any fluid.
Is there a switch that could be going bad on me?
 
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