Brake warning light coming up intermittently

Leandro

Leandro

Joined
Oct 10, 2016
Messages
915
Location
Middle Tennessee
hey guys.
This morning on my way to work my emergency brake light on the dash came on.
When I hit the brakes it turns off for a few seconds and then it comes back on.
The truck brakes normally, can't notice any difference.
When I got to the office I checked the brake fluid and is half way between MIN and MAX.
eBrake lever has been seized for who knows how long, when I bought the truck over 5 years was already seized.

Any ideas what can be causing it?

I did some "light search" on the forum, but can't spend much time right now since I'm at work.
 
Last edited:
AlpineAccess

AlpineAccess

Joined
Apr 16, 2019
Messages
1,948
Location
Colorado
hey guys.
This morning on my way to work my emergency brake light on the dash came on.
When I hit the brakes it turns off for a few seconds and then it comes back on.
The truck brakes normally, can't notice any difference.
When I got to the office I checked the brake fluid and is half way between MIN and MAX.
eBrake lever has been seized for who knows how long, when I bought the truck over 5 years was already seized.

Any ideas what can be causing it?

I did some "light search" on the forum, but can't spend much time right now since I'm at work.

Do the booster time test; pump the pedal 40 times until it goes to the floor and time the pump runtime when you key the ignition. Sounds like a booster motor issue but this would be one thing to start a diagnosis with.
 
K

KFunk740

Joined
Dec 4, 2017
Messages
282
Location
Shade, Ohio
You sure you checked the fluid properly? You have to shut off the engine and pump the brake pedal 40+ times until the pedal drops, then check. It should be at max, top off as necessary. If fluid is too low, the light can blink intermittently. You definitely want to look for brake fluid puddles anywhere. May want to double check for wet spots around each caliper and fitting on m/c, or any other possible leaks.
If the fluid level is at max after pumping brakes, and the light still flashes, then you may want to do more diagnostics. If it were a booster issue, I'd think it'd be buzzing loudly, as those usually do. But things can fail in weird and exciting ways.
 
Leandro

Leandro

Joined
Oct 10, 2016
Messages
915
Location
Middle Tennessee
You sure you checked the fluid properly? You have to shut off the engine and pump the brake pedal 40+ times until the pedal drops, then check. It should be at max, top off as necessary. If fluid is too low, the light can blink intermittently. You definitely want to look for brake fluid puddles anywhere. May want to double check for wet spots around each caliper and fitting on m/c, or any other possible leaks.
If the fluid level is at max after pumping brakes, and the light still flashes, then you may want to do more diagnostics. If it were a booster issue, I'd think it'd be buzzing loudly, as those usually do. But things can fail in weird and exciting ways.
Definitely didn't do the pump 40 times thing, just parked, stopped the engine, opened the hood and visually checked.
Will try that before going home tonight.
 
Leandro

Leandro

Joined
Oct 10, 2016
Messages
915
Location
Middle Tennessee
Do the booster time test; pump the pedal 40 times until it goes to the floor and time the pump runtime when you key the ignition. Sounds like a booster motor issue but this would be one thing to start a diagnosis with.
thanks, will try that tonight.
 
Leandro

Leandro

Joined
Oct 10, 2016
Messages
915
Location
Middle Tennessee
Found the problem.
I have a leak in the rear left tire. Coming out of the control arm bracket in the frame, so I assume it's on the pipe and not in the hose.
I found a project for the holiday weekend.
 
AlpineAccess

AlpineAccess

Joined
Apr 16, 2019
Messages
1,948
Location
Colorado
Found the problem.
I have a leak in the rear left tire. Coming out of the control arm bracket in the frame, so I assume it's on the pipe and not in the hose.
I found a project for the holiday weekend.
Good find and good to see the master cylinder leak down caught it.
 

Users who are viewing this thread

Top Bottom