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Emergency Brake Light and ABS

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Old 11-14-2011, 06:50 PM
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Default Emergency Brake Light and ABS

I recently had cause for my parking brake to be engaged for about two weeks. When I disengaged the brake (and it is fully disengaged at the drum) the Brake light stays on, and I think as a result, my 'Rear ABS' light is staying on. When I push the parking brake in, the metal contact appears to engage, and when I disengage the brake, it "appears" that the contact is breaking, but the light is staying on. I don't believe I have any actual brake functional issues, I suspect there's just an issues with the contacts.

Is there a plunger in there that's possibly not moving since I had it in so long?
Old 11-14-2011, 07:35 PM
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There is a fault in the braking system, possibly air in the system or a leak. The ABS is disabled when there is a brake fault so the ABS light comes on. If it were a problem with the parking brake the ABS light would not be on too.
Old 11-14-2011, 08:30 PM
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There doesn't appear to be any external leaks....I suppose I could bleed the rear lines again to see if that helps, but there wasn't any air left after bleeding them the other day.

Why would a fault in the brake line effect the parking brake light? My braking doesn't seem compromised. My ABS light being on isn't actually creating a code that I could get read at my local auto parts store, is it?


Originally Posted by Just call me Sean
There is a fault in the braking system, possibly air in the system or a leak. The ABS is disabled when there is a brake fault so the ABS light comes on. If it were a problem with the parking brake the ABS light would not be on too.
Old 11-14-2011, 08:49 PM
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The brake light doesn't just tell you the parking brake is on, it also tells you there is a fault in the system.
Old 11-14-2011, 10:29 PM
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I rarely use my parking brake, so when I got a leak, the light was on and I pulled the release and didn't fix it. Those brake lines can be tricky. I checked all of my lines and didn't see the leak, thought it was the master cylinder, so I bought a new one, got under the truck one last time before I started to take off the MC and found the leak. Double, if not triple check for a leak, it may be tiny, so not much fluid would be around it right away.
Old 11-15-2011, 09:11 PM
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Alright, let me make sure we're all talking about the same equipment. This is a 92, 4.9, 5 speed, base model. Where is the system measuring a delta P across the brake line system? I have two electrical connections on the brakes; a contact that tells me the e-brake is depressed (referenced above), and the RABS sensor (which is on the pumpkin). If you all are telling me I have a fault, what is measuring the fault? If the fault is caused by a leak, what pressure transducer is measuring the pressure drop?

As a background, one of my brake lines broke and a friend drove it for about 10 miles (don't ask) without either the ABS or the e-brake light coming on. If a gaping hole that pours brake fluid on the ground doesn't trigger the light, I can't believe a pin size hole that isn't actually leaking externally would cause the leak.
Old 11-15-2011, 09:30 PM
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Obviously you can't handle this problem. Take it to a brake shop before you kill someone, so they can tell you the same thing we did.
Old 11-15-2011, 10:34 PM
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So you can't actually answer my above question? If a light is turning on, an electrical signal is being sent. How is a hydraulic system leak being converted to an electrical signal?

I have no trouble bleeding the brakes again and checking for leaks. I'm just asking someone to explain to me how a leak is sending an electrical signal.

Originally Posted by Just call me Sean
Obviously you can't handle this problem. Take it to a brake shop before you kill someone, so they can tell you the same thing we did.
Old 11-15-2011, 10:42 PM
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Originally Posted by farmerjg
So you can't actually answer my above question? If a light is turning on, an electrical signal is being sent. How is a hydraulic system leak being converted to an electrical signal?

I have no trouble bleeding the brakes again and checking for leaks. I'm just asking someone to explain to me how a leak is sending an electrical signal.
He did answer your question, if you have a fault in your system (air in the lines) the brake light indicates a fault from reading the low hydraulic pressure. In turn the ABS light turns on, telling you its disabled to prevent damage. Its an almost full proof system, possibly air in the master itself.

Last edited by sylver91; 11-17-2011 at 07:26 PM.
Old 11-15-2011, 10:51 PM
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The ABS light is bad, the parking brake light may be fixable easily. I think I misunderstood your issues, but hey, maybe not.

Actually, If you read this before you take it in, you might save a little cash. Or maybe I'm totally off. But its worth checkin first.

This assumes your brakes work. Your truck stops safely. You aren't gonna kill me at an intersection tomorrow. Or perhaps, you have another car to drive until you resolve this. If this is all really confusing, better to take Sean's advice and have a mechanic look at it before you die.

If you are sure you are getting stopping power, or can let your truck sit until you are sure, try the following...

I had the brake light a few years back, and then again this summer. The foot pedal parking brake connects to a small plunger above the assembly that turns the light on and off on your dash when you use the parking brake. Regardless of whether or not your brakes are functioning. I have an "ABS" light that tells me my brakes are unsafe, It has mostly meant low fluid, topping off every few years has resolved that light. My "Parking Brake" lamp is seperate. But I believe it has gone on for multiple reasons, I cant really keep track. I drive a Ford and lights come and go. Know before you go!!!! Doesn't mean this lamp situation is true for you. Your truck may differ. Do not drive until you are clear on your situation.

Couple things to look at while you aren't running stoplights in your truck and are driving a safer vehicle:

1- Park on a level piece of ground where your truck won't roll away.

2- with motor running set your brake. The brake indicator light is now on, on your dash, right?

3- Release the parking brake. From what you have said, it sounds like your parking brake is releasing, but your light stays on. Truck can drive without noticeable brake restriction. Don't drive it, I'm just askin. Am I on the right track?

If yes... follow along.

If no, ignore me.

If sometimes, play along, maybe we are close to a cheap fix for a problem unrelated to brake hydraulics.

4- with brake indicator on, and brake released, open up your door, get out, and get on your knees where you can reach and see the parking brake pedal assembly from floor to dash and get a view of the dash light as well.

(you guys are dirty, just cuz I told him to get on his knees, doesn't mean I'm yankin his chain)

5- ok, brake is released right? Lamp is on right? Pull on the foot pedal and move it upward toward the dash as if you were continuing to release it further.

My truck, has a small plastic plunger above the lever portion of the pedal. Toward the underside of the dash. If the pedal doesn't release fully, even though the brakes are released, the light stays on until that plunger is engaged. If you see the little white plastic plunger, but your lever won't hit it, just push it in with your finger to see what happens to your dash indicator light. Or pull the pedal up until it engages the plunger.

Are we gettin anywhere yet?

If none of this applies to your parking brake assembly, discontinue now. 2nd warning. If we are talking the same language, continue reading.

6- If we are moving forward, then we just need to know why your brakes are loose but pedal isn't hitting the plunger to extinguish the dash light. 2 options I know of.

6a- the spring on your parking brake assembly is ... falling off, has no rebound left... or missing. OR

6b- the nut on your parking brake assembly needs to be tightened. (If your undercarriage nuts and bolts look like mine, pray for 6a)

7- Since you are on the ground at the drivers door, scooch on down under your truck toward the rear drivers tire along the outer side of the frame. You should see your parking brake cable connecting to 2 rear brake cables by some sort of bolt and metal T that transmits one cable to two brake lines. Do you have that? I do. And mine has a spring that extends from the loose end of the single bolt and cable, to the welded on brake cable flange-a-majiggy. When my spring falls off, or is otherwise not tight like your little sisters hoo-ha, my parking brake pedal does not release high enough to engage the light extinguishing plunger under the dash. I would check to see if you have a spring, and if it is properly aligned to put release pressure on your pedal. Pressure from the spring when brake is released = pressure on the lever = engage the light bulb off plunger. Hopefully problem solved.

8- If yours is assembled this way, but that doesn't solve your problem, try tightening the nut. This can be a serious pain in the ***. But if all other brake functions work, you got time right?

I'm gonna pause till you take a look or respond, cause otherwise, I may dig an even deeper hole. But seriously... I've had this happen several times. It was always the spring. I haven't lost the spring yet, but I can't imagine it couldn't be diagnosed and replaced for less than 3 minutes and 3 bucks if thats the issue. The bolt could be the same cost, or less, if it turns. Otherwise 3 bucks and 3 weeks.

Let me know what you find.

Last edited by 91straight6beater; 11-15-2011 at 11:00 PM.


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