E4od and the brake light
- Thread starter Selahdoor
- Start date
gandalf
Senior Member
My understanding is as follows. If you hit the brakes the torque converter will unlock. Otherwise you could, conceivably, come to the point, as you slow, where you're telling the truck to stop, and the engine/torque converter is telling the truck to go. Taking this as true, if the truck "thinks" that the brakes have been applied, it will unlock the torque converter.
Test this: cruise at a constant speed, note the RPM on the tach, the just touch the brakes and watch the tack jump about 200 RPM.
Test this: cruise at a constant speed, note the RPM on the tach, the just touch the brakes and watch the tack jump about 200 RPM.
Selahdoor
How can I help you, or make you laugh, today?
That's exactly the test I intended to do tomorrow. Thank you.
I'll do this when at at least 55mph. The brake light should be on. This way, if the brake light doesn't affect the lockup, I'll find that out.
(Brake light comes on, and stays on at ~40mph.)
I'll do this when at at least 55mph. The brake light should be on. This way, if the brake light doesn't affect the lockup, I'll find that out.
(Brake light comes on, and stays on at ~40mph.)
Slicknik
Full Access Member
Just a FYI , the brake light will also come on when you have low vacuum pressure as well,
The “brake light” has many different functions in the ford truck,
The “brake light” has many different functions in the ford truck,
Slicknik
Full Access Member
I believe the brake light will also come on when your low on brake fluid as well
Don’t quote me on that though!,
I’ll have to look in my book but there are several different indicators that use the brake light as a warning to the driver that something is up with your truck
Don’t quote me on that though!,
I’ll have to look in my book but there are several different indicators that use the brake light as a warning to the driver that something is up with your truck
chillman88
Full Access Member
I'm wondering if the brake light might be tied into the ABS system at all? My thought is if it's reading the abs sensor wrong might be what's tripping it, any ABS light on?
I'm just trying to wrap my head around why it would only come on over 40mph and go out when you restart the truck until you get over 40 again, that's pretty odd...
Do you have a vacuum gauge you can run in a spot visible while driving just to rule out some odd vacuum leak?
Just so everyone is clear, we are talking about the light on the dash right @Selahdoor?
I'm just trying to wrap my head around why it would only come on over 40mph and go out when you restart the truck until you get over 40 again, that's pretty odd...
Do you have a vacuum gauge you can run in a spot visible while driving just to rule out some odd vacuum leak?
Just so everyone is clear, we are talking about the light on the dash right @Selahdoor?
Also, which brake light is it?
The red BRAKE light, or the yellow Rear ABS light? Since these trucks have 2 lights associated with the brakes.
As mentioned, the red BRAKE light will come on when there is a failed line and the little actuator moves from center and turns the light on. Also, if the parking brake is set, or you have a vacuum issue. I don’t think they have a low fluid sensor, but many be incorrect on that one.
One thing to check if the front brakes are hanging up (this shouldn’t cause the light to come on) is replace the soft brake hoses from the frame to the calipers. The inside of the hose can break down, and create a “check valve” effect, where when you push the pedal, the pressure pushes the “valve” open and the brakes function normally. But when you release the pedal, the “valve” closes and restricts the fluid from moving out of the calipers. I’ve seen many chase this one. Replace everything in the system except the hoses because “they look fine”......
The red BRAKE light, or the yellow Rear ABS light? Since these trucks have 2 lights associated with the brakes.
As mentioned, the red BRAKE light will come on when there is a failed line and the little actuator moves from center and turns the light on. Also, if the parking brake is set, or you have a vacuum issue. I don’t think they have a low fluid sensor, but many be incorrect on that one.
One thing to check if the front brakes are hanging up (this shouldn’t cause the light to come on) is replace the soft brake hoses from the frame to the calipers. The inside of the hose can break down, and create a “check valve” effect, where when you push the pedal, the pressure pushes the “valve” open and the brakes function normally. But when you release the pedal, the “valve” closes and restricts the fluid from moving out of the calipers. I’ve seen many chase this one. Replace everything in the system except the hoses because “they look fine”......
Selahdoor
How can I help you, or make you laugh, today?
Yes, the red light on the dash.
And one of my first thoughts was to wonder if the ABS had anything to do with it. I asked them to bypass the ABS. But they never responded to that, and it isn't mentioned in the work sheet.
I'll get a pic of it sometime today. It's the red light in the lower right corner of the dash.
They couldn't get the parking brake cables to reconnect, once they replaced the entire rear brakes. (Drums, cylinders, axle seal, shoes, shoes, hardware, the entire thing.) So they left it all disconnected. They couldn't locate replacement cables. I am remembering something here about a certain way to fix that via a little piece of plastic on the pedal assembly. I'll look into that. (Although there was a white plastic piece on the seat, that looked a lot like the piece on the parking brake assembly. So we'll see...)
I tried prying up on the brake pedal, and on the parking brake pedal, to no avail. Light stayed on.
Brand new rubber hoses on the front.
nj_m715
government's finest
this is the same shop that cant find fuel senders?
I found this in 30 seconds
https://www.partsgeek.com/mmparts/parking_brake_cable/ford/f250.html
I found this in 30 seconds
https://www.partsgeek.com/mmparts/parking_brake_cable/ford/f250.html
Selahdoor
How can I help you, or make you laugh, today?
I think they have a different standard for finding parts than we do. They have a pretty good warranty. I think they buy parts with a much more jaundiced eye than I would, because of the warranty. Other than that, I don't know what else to say, to explain it.
They'll put on parts that I buy and bring them, but they won't warranty it. Which is understandable.
Selahdoor
How can I help you, or make you laugh, today?
Ok... So, overdrive, and the lock up torque converter are two different things, no?
Get up to 60mph... Tap the brakes... No difference whatever in RPMs.
But, get to 60... RPMs are ~1500-1600... It has definitely shifted into 4th. Now, push the overdrive button on the stalk... Immediate change in the transmission, and immediate jump to at least 2200 RPMs.
~~~
Also today: Brake light and ABS light both come on when the key is turned. The ABS light goes out. But the brake light stays on forever.
Also, first time applying the brake, at startup, brake pedal goes way down, and is spongy.
For the remainder of the test driving, the brake pedal travels further than I think it should, but the brakes stop the truck admirably.
You CAN make the pedal a bit better by pumping it.
chillman88
Full Access Member
Correct.
Sounds like it's going into overdrive but not locking up the way you are describing it.
Now that sounds like improperly adjusted rear shoes to me....
chillman88
Full Access Member
I would be testing the vacuum system at this point. That would be step #1 for me as it's a common issue.
trackspeeder
Stone crusher.
If you push the OD OFF button at 60 you will get a big change in RPM. Because its now in third gear.
