Brake warning light on dash

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71Demon

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What would cause the brake warning light come on when applying the brakes. This is a 69 Dart that has a sensor on the distribution block. Is it air in the lines? or too low of hyd pressure that this sensor detects? It was converted to 4 wheel disc brakes by SSBC and now not stoping good at all. Brake warning light comes on if you really push hard on the pedal to try and make it stop.
 
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Air or a failure in the front or rear brakes sets.
When only the front or rear brakes get pressure it pushes the switch off center and causes the light to come on.
Start with bleeding and go from there.
 
look on the backs of your backing plates and on the inside/outside of the firewall for signs of leakage too
 
TrailBeast said:
Air or a failure in the front or rear brakes sets.
When only the front or rear brakes get pressure it pushes the switch off center and causes the light to come on.
Start with bleeding and go from there.
Click to expand...
Thanks.
 
Re-read the post, see above.
 
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Very good if your warning switch is still working. Most get rusted in place. I think the emergency brake handle switch triggers the same lamp. Both short to ground to light it, so if either wire shorts to ground that would as well. For those w/ later Mopars (my 1996) or if you install a later MC (my A's), the reservoir low-level sensor similarly shorts to ground to light the same lamp.
 
The light turns on when there is UNEVEN pressure. If the fluid level is constant, its probably not from a leak. When you say brakes dont work very well, do you mean none of the wheels will lock up ? Front only ? Rear only? I would look at master not being bled properly, was it bench bled? Did they install the calipers with bleeders pointing up? You can try bleeding again, start at RR, LR, RF, LF in that order. Tap on each caliper with screw driver handle to get bubbles that cling to caliper walls to break free. Pump 3 times SLOWLY and hold so you dont create air bubbles by agitating fluid. I that doesnt work, you most likely have bad master. Look at master with cover off and SLOWLY have someone depress pedal, look for air bubbles coming into master, which indicates bad bench bleed or most likely bad master.
SSBC masters dont have low level sensor and e brake switch being bad would make light stay on and brakes would probably work. 1996 mini van master has nothing to do with A body disk conversion....
 
A hard pedal is the first thing you need, and it has to be hard on the first pump, and long before the pedal gets to the floor.
I'd bet you a dollar that the front brakes are not working or working very poorly.And it may be on account of insufficient fluid displacement due to the bore size in the M/C.But we'll get to that later. Now,Back to the top.
 
Well after throwing away the NEW 7/8 bore wilwood master cylinder that would never bleed all the air out I put a stock standard drum/disc master cylinder on and I have a solid pedal and light is off. Now my question is, it appears there is residual pressure on the rear calipers. I am assuming from what I have heard the residual valve must be removed when doing 4 wheel discs. Which port is it on? The port that goes to the rear wheels with small reservoir and farther from firewall? After bleeding I cracked the rear bleeder and a small amount of fluid did come out without pedal applied. Ive seen after a google search to put a screw in the port a pull it out. correct? Thanks
 
Yes to all
The front most chamber, if plumbed correctly, feeds the rear brakes. and the R valve seats can be popped out with a screw. Then you remove the guts, and reinstall the tube-seat, after having repaired any damage that may have occurred to them.
 
AJ/FormS said:
Yes to all
The front most chamber, if plumbed correctly, feeds the rear brakes. and the R valve seats can be popped out with a screw. Then you remove the guts, and reinstall the tube-seat, after having repaired any damage that may have occurred to them.
Click to expand...
Got it thanks.
 
Before dissing the Wilwood MC, you should detail how you bled the air out. It often takes 50 strokes to bench-bleed an MC (youtube). Hard to believe they have an endemic problem of "can't bleed it".
 
OK ill try it again later but I have ordered the factory aluminum15/16 master from Diff Dr to see if that helps any. I do like the looks of the wilwood much better. Thanks
 
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