Brake light is on
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Senior User
Joined: Jul 2003
Posts: 101
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From: Colorado
Brake light is on
My 1991 F250 7.3L Diesel 4x4 brake light comes on intermittently. It seems like it could be a vacum issue but I'm not sure. Basically what happens is when I come to stop, the light comes on, and after I take off, it goes off. For the most part that brakes work as expected. However, on occasion when I'm pulling into a parking spot the pressure in the brake pedal will increase significantly, but the stopping power decrease significantly.
Any ideas?
Also, the rotors and pads are new and the calipers were rebuilt. The brake lines are still rubber. Any good web sites where I could get steel braided lines for her?
The rear brakes are drum brakes and haven't been serviced in the last 4 years.
Thanks,
Bart
Any ideas?
Also, the rotors and pads are new and the calipers were rebuilt. The brake lines are still rubber. Any good web sites where I could get steel braided lines for her?
The rear brakes are drum brakes and haven't been serviced in the last 4 years.
Thanks,
Bart
New User
Joined: Feb 2004
Posts: 16
Likes: 0
From: Grass Valley, CA
I think you are right on the vacuum issue.
The vacuum booster pump could be going or you may have a slow leak and it can't keep up at idle.
The diesel engine supplement for my 94 350 says low vacuum pressure will cause the brake warning light to come on and give a HARD petal.
There are some good threads on vacuum pump issues with diesel F-series.
I have a similar issue where the brake warning light will start to glow when I'm at speed with cruise on.
It never really comes on all the way, but sort of ghosts lightly.
It doesn't happen very often, and I think it is vacuum related too.
Maybe you can check the vacuum pressure at idle and with the engine revved to see if there is a difference.
On my truck there is a vacuum block on the drivers side fender wall that has extra capped ports where a vacuum gauge could be easily connected.
I'm not sure what the optimal pressure should be, but any major difference would point to a problem.
Good luck.
The vacuum booster pump could be going or you may have a slow leak and it can't keep up at idle.
The diesel engine supplement for my 94 350 says low vacuum pressure will cause the brake warning light to come on and give a HARD petal.
There are some good threads on vacuum pump issues with diesel F-series.
I have a similar issue where the brake warning light will start to glow when I'm at speed with cruise on.
It never really comes on all the way, but sort of ghosts lightly.
It doesn't happen very often, and I think it is vacuum related too.
Maybe you can check the vacuum pressure at idle and with the engine revved to see if there is a difference.
On my truck there is a vacuum block on the drivers side fender wall that has extra capped ports where a vacuum gauge could be easily connected.
I'm not sure what the optimal pressure should be, but any major difference would point to a problem.
Good luck.
Hotshot
Joined: Oct 2003
Posts: 17,799
Likes: 103
From: Ashland City, TN
The ebrake light?
Mine comes on all the time. Its going out now though, cause i'm useing the Ebrake more.
Check your cables to the rear of the vehicle and make sure there lubricated properly.
Mine comes on all the time. Its going out now though, cause i'm useing the Ebrake more.
Check your cables to the rear of the vehicle and make sure there lubricated properly.
New User
Joined: Feb 2004
Posts: 16
Likes: 0
From: Grass Valley, CA
On my 94 the brake light is dual purpose.
It is the Emergency/Parking brake indicator and a brake system warning light.
It seems to work correctly when I apply/release the parking break.
I will check the cables to be sure.
Thanks for the idea.
It is the Emergency/Parking brake indicator and a brake system warning light.
It seems to work correctly when I apply/release the parking break.
I will check the cables to be sure.
Thanks for the idea.
