Parking brake fail? Wet, not icy surface

[evowner]

I don't understand the mental gymnastics people are subjecting themselves to here. Oh no the parking brake won't hold the truck on a solid sheet of ice!! No crap. The parking also will not let the truck swim, and also won't cook you breakfast. This is not a limitation or flaw in the vehicle. This is what happens on ice. To everyone and everything.

I believe you are wrong. The Lightning will cook you breakfast..

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[Peddyr]

I have a drag system, but my Father in law was worried about the wheels on the garbage can wearing out....can't make this stuff up.

Funny you should mention that. Few years back the axle on the barrel went belly up so I had to bring it to the transfer station to swap it out. Guy looks at it and says "You been drag racing with this thing? Told him about our long driveway and mentioned that I have 9 kids. Got a commercial size barrel out of the deal so it all worked out.

 

[Wattsgas]

So I know that I am part of hijacking the original thread, but, today I have had a hell of a time getting my emergency brake to come on. In two years I have never had an issue. The automatic brake set hasn't been turning on when I am on a slope. So, I have tried setting it with the switch. Only to see the emergency brake light illuminate and then turn off. My thought is that the screen display and the truck computer are lagging, maybe, slower than my patience. I was doing trash duty, so was in and out of the truck a bunch. So, I'm thinking that maybe this could be a new bug. I did do a sync reset and haven't had the issue this afternoon. Weird.

 

[Henry Ford]

So I know that I am part of hijacking the original thread, but, today I have had a hell of a time getting my emergency brake to come on. In two years I have never had an issue. The automatic brake set hasn't been turning on when I am on a slope. So, I have tried setting it with the switch. Only to see the emergency brake light illuminate and then turn off. My thought is that the screen display and the truck computer are lagging, maybe, slower than my patience. I was doing trash duty, so was in and out of the truck a bunch. So, I'm thinking that maybe this could be a new bug. I did do a sync reset and haven't had the issue this afternoon. Weird.

Exactly how do you set the parking brake? First eliminate user error then move on to other possibilities.

 

[Wattsgas]

Exactly how do you set the parking brake? First eliminate user error then move on to other possibilities.

Well. First I put the truck in Park. 2nd, I look at the instrument cluster and verify if the truck has the parking brake symbol is displayed. This step is affected by slope. If the truck is level it doesn't come on/if I'm parked on a slope it usually engages. If I want the emergency brake on, I tug on the brake lever. Step 3 verify the emergency brake symbol is on the dash cluster.

I started checking these steps off because of hitching up to my trailers. If I go to drop the receiver on the trailer without the emergency brake being set the truck shifts and I can't get the hitch set. The Lightning is much more prone to moving with out the emergency brake than my Super Duty. Just an observation.

Today I noticed it was a little more difficult to get it to set. Never had the issue before. Just noticed it today. My guess is the computer was slow in turning on the dash light, and, I was quick at pulling the emergency brake switch a second time which most likely turned it off. I think that the truck and I were out of sync. So maybe that was the issue the OP was experiencing. Not sure that it would be intuitive for someone not used to the Lightning.

 

[Henry Ford]

I started checking these steps off because of hitching up to my trailers. If I go to drop the receiver on the trailer without the emergency brake being set the truck shifts and I can't get the hitch set. The Lightning is much more prone to moving with out the emergency brake than my Super Duty. Just an observation.

Good technique, I do the same thing. Nothing more annoying than getting lined up perfectly then having the truck shift.

Today I noticed it was a little more difficult to get it to set. Never had the issue before. Just noticed it today. My guess is the computer was slow in turning on the dash light, and, I was quick at pulling the emergency brake switch a second time which most likely turned it off. I think that the truck and I were out of sync. So maybe that was the issue the OP was experiencing. Not sure that it would be intuitive for someone not used to the Lightning.

To set the parking brake pull the parking brake lever. To release the parking brake, press the brake and press the parking brake lever at the same time. Alternatively, you can release the brake by putting the truck in Reverse or Drive and applying the accelerator.

When applying the parking brake you should hear the stepper motor engage the brake. Pulling the parking brake lever will not release the brake.

I'm not sure what your issue is but my suggestion is to hold the lever until the brake is on. Maybe you momentarily pulled the lever but a more deliberate pull is necessary.

 

[NW Ontario Ford Lightning]

The “mental gymnastics” you’re referring to here is kind of a moot point. This wasn’t a thread about a truck sliding down the hill, although thats likely what happened. This was about the OP believing there was a mechanical failure. Allowing it to keyword here, Roll.

Can the OP/Admins up-date the Thread Title - for accuracy.

 

[Effonefiddy Lightning]

No, in fact, I've had cars that lock only 1 rear wheel by design. One was manual trans to boot so I could have easily left it in neutral.

Electronic parking brakes use a motor inside the caliper to drive the pads on, no pesky cables to break or seize

Salt and sand are your friends in the winter. If you have an inclined driveway then you should be prepared for winter. The truck is great! Operator error is not the trucks fault.

Just take responsibility for your actions, shit happens. It's not ford's fault that they built an electric f150 that has most of the same systems as every other f150.
Also, the stock all season tires aren't that good for winter weather. One of the big advantages of winter rated tires is that the rubber compound has better adhesion when the temperature drops.

I don't have Ice, I was concerned about the parking brake failure.

 

[Firn]

I don't have Ice, I was concerned about the parking brake failure.

There was no parking brake failure...that's the point

 

[RickKeen]

The Lightning parking brakes are only on the rear axle. The front axle has no parking brake action. The weight distribution of the Lightning is apx 50-50 between the two axles. So if the coefficient of friction of the rear tires goes to less than 50% of the grade of the hill, then the truck is going to slide down the hill.

Ice is damned slippery. The coeff of friction of tires on ice is down around 10%. With only one axle braking, 50% of 10% means the truck held by just the rear axle parking brakes will slide down a 5% grade on ice.

Note on e-brakes:
The e-brake on the lightning is on the two rear brake calipers. It is an electric worm-driven threaded-drive actuator that pushes on the back of the hydraulic cylinder to engage the brake caliper with fairly high force. There is an actuator on both brake calipers on the rear axle. Unlikely the e-brake clamping force is insufficient unless the e-brakes are completely failed and not actuating.

Anecdotal stories of holding on the slippery slope with the AWD or the driving brakes but sliding with just the parking brake are likely explained not by the parking brakes having failed, but by the fact that the driving brakes on the front axle doubles the available friction.

Note on Parking Pawl:
Perhaps even worse if just the parking pawl is engaged. It locks the axle before the differential. Not clear if the diff lock gets engaged as well. If the rear diff is not locked, then the differential would still be active and if one wheel slips on ice the other wheel on the rear axle is just going to turn due to the diff. In that situation, if the coefficient of friction is less than 25% of the grade, the truck is at risk of sliding. On ice, that could be as low as only a 2.5% grade.

 

[MaintGrl]

The Lightning parking brakes are only on the rear axle. The front axle has no parking brake action. The weight distribution of the Lightning is apx 50-50 between the two axles. So if the coefficient of friction of the rear tires goes to less than 50% of the grade of the hill, then the truck is going to slide down the hill.

Ice is damned slippery. The coeff of friction of tires on ice is down around 10%. With only one axle braking, 50% of 10% means the truck held by just the rear axle parking brakes will slide down a 5% grade on ice.

Note on e-brakes:
The e-brake on the lightning is on the two rear brake calipers. It is an electric worm-driven threaded-drive actuator that pushes on the back of the hydraulic cylinder to engage the brake caliper with fairly high force. There is an actuator on both brake calipers on the rear axle. Unlikely the e-brake clamping force is insufficient unless the e-brakes are completely failed and not actuating.

Anecdotal stories of holding on the slippery slope with the AWD or the driving brakes but sliding with just the parking brake are likely explained not by the parking brakes having failed, but by the fact that the driving brakes on the front axle doubles the available friction.

Note on Parking Pawl:
Perhaps even worse if just the parking pawl is engaged. It locks the axle before the differential. Not clear if the diff lock gets engaged as well. If the rear diff is not locked, then the differential would still be active and if one wheel slips on ice the other wheel on the rear axle is just going to turn due to the diff. In that situation, if the coefficient of friction is less than 25% of the grade, the truck is at risk of sliding. On ice, that could be as low as only a 2.5% grade.

Yes, I understand, and thank you for the explanation . . appreciate it...

 

[nofreecell]

Are you sure.....

But it was upper 30s and a light rain. Not a solid sheet of ice. And my son has been parking in the same spot all winter

 

[nofreecell]

It is possible the parking pawl is broken and you weren't putting the brake on.




Are you parking on an icy hill still?

It will take all of less than 5 minutes to test your truck parking systems.

Dealership came and got the truck first thing Monday morning . Had not looked at it as of yesterday. We ordered the

Happened in his garage as well

I’m assuming that floor was fairly level and dry

No did not happen in the garage: my son is post op from major surgery so not supposed to be outside and the truck won’t fit in his garage anyway

 

[nofreecell]

You are correct sir. I had to reread the original post. I could’ve swore i read him say something about being pinned against the wall in the garage. Now that has me wondering if he was reversing into the parking spot like the video of the other guy sliding down the hill?? may be having your “anchor” tires on the downhill side would be better. Due to lack of reply from the OP we may never know.

Wasn’t reversing

 

[nofreecell]

Are you sure.....

I have lived in snow country for decades (Syracuse, Buffalo, Central Oregon). One question I had was when that person jumped back into his truck and hit the brakes, why did he stop? We have all hit black ice (I did a 180 in a toyota vehicle off I 90 near Utica NY once and drove away from it). Would be nice if the service department told us they couldn’t find anything and we buy new tires, parking bumpers and replacement charger cord and go on our way all the wiser. Now will have a rental car over the weekend which if the truck is fine is an added unnecessary expense.

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