Brake warning light
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More Turbo
Joined: Nov 2002
Posts: 543
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From: Tulsa
Brake warning light
The red brake light on the dash of my '86 f250 won't go off. I don't know what the deal is. MY e-brake isn't on or stuck. The pedal does seem to be a little mushy. And I have to push pretty hard on the pedal to come to a complete stop. what's this an indication of? I havn't found any brake fluid on the ground, so I'm almost sure it's not leaking. There is, however, some bubbling on the paint of the booster where it meats the mast. cyl. Could there be a leak here? I really don't know what I should be looking for here. 
Last edited by Xwarrior86; Mar 5, 2003 at 12:45 AM.
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Joined: Jan 2008
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Likes: 24
Brake warning light
Yep, That's the brake failure light.
You havea leak somewhere that the equalizing pressure is gone.
Probably out the back or primary reservoir.
Change the M/C if it's leaking out the back of the M/C
You havea leak somewhere that the equalizing pressure is gone.
Probably out the back or primary reservoir.
Change the M/C if it's leaking out the back of the M/C
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More Turbo
Joined: Nov 2002
Posts: 543
Likes: 7
From: Tulsa
Brake warning light
I went out and checked the fluid in the reservoir this morning and only the front portion seems to be low. Could there just be air in the lines and bleeding could be the answer?
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Joined: Jan 2001
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From: Virginia
Brake warning light
I just went through this myself. The small front reservoir is the rear brakes. The large rear reservoir is the front brakes. My pedal got low, and the small reservoir was empty. I didn't see any leaks out of the back wheels, or along the frame, so I refilled it and bled the rear brakes.
A week later I checked it again and it was getting low. I pulled both rear wheels off to make sure the wheel cylinders weren't leaking, and checked the rear lines again. I noticed too that there was a little dampness on the booster, so this was the only place the fluid could be going. I replaced the master cylinder and everything is fine now.
Do a little troubleshooting and you will eventually find the problem.
A week later I checked it again and it was getting low. I pulled both rear wheels off to make sure the wheel cylinders weren't leaking, and checked the rear lines again. I noticed too that there was a little dampness on the booster, so this was the only place the fluid could be going. I replaced the master cylinder and everything is fine now.
Do a little troubleshooting and you will eventually find the problem.
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More Turbo
Joined: Nov 2002
Posts: 543
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From: Tulsa
Brake warning light
Screw the trouble shooting. There's Brake fluid on my floor boards now! However, I think I know what the deal is. Back up under the dash there is and pneumatic emergency switch for the brakes on a fifth wheel trailer. (previous owner used to haul cattle around) Well, I think that the fittings have come loose back around there. (I hope) if so, it'll be a pretty simple fix I think. JUst pull the unit and the lines out and plug the fittings that are attatched to the M/C. KNow what I mean. HOpefull this will do the trick. Any other thoughts on how B/F could be inside the cab on the floor boards?
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More Turbo
Joined: Nov 2002
Posts: 543
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From: Tulsa
Brake warning light
Well, I was right. It was that pneumatic emergency fifth wheel brake switch. OVer the last fifteen years the brake fluid has coroded all the rubber and plastic seals. BUt I still don't have any pressure behind the peddal. I bet there's air in the line. Will probably have to bleed them. What's the process? Start with the rear passenger side, then to the other side, passenger front, then driver's front? Is that how it goes? Now I just need to find someone to push the brake pedal while I take care of the lines.
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Post Fiend
Joined: Nov 2002
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From: Memphis, TN
Brake warning light
You can bleed brakes alone with a MityVac, and it's good for checking the vacuum system, too.
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Joined: Jan 2001
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From: Virginia
Brake warning light
Cross your fingers and hope you don't break any of the bleeder screws off(very easy to do). I did this, and ended up trying to bleed it by loosening the brake line. Not totally satisfied, I replaced the wheels cylinders in the back. Not a bad job on a F150, but if you have a full-floating rear axle, I hear it's a pretty big job. And when you go to change the wheel cylinders, the brake line may be frozen to the nut. I had to replace the lines from the wheel cylinders to the rubber hose/tee fitting.
Isn't working on old trucks fun?
Isn't working on old trucks fun?
