Burning Smell From Front Wheels

Traveling downhill on a steep and narrow rocky mountain pass, first gear only, can't go faster than two to three MPH, in 4H mode.

After a while of this (20 minutes?) of riding the brakes to control the descent we had a distinct burning smell. I got out of the car and it was coming from the front wheels, not the engine, not the rear wheels.

I installed new front rotors and front severe duty pads (all Motorcraft) about three months ago.

When I got off the mountain pass and back into town no vibration felt, no brake fade, all seemed normal.

My questions are - is the burning smell normal for severe duty pads when under a lot of use? Could it have been from the 4H mode? If it's not normal then how to avoid in this specific situation?

Thanks! Groover

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Thanks but I've driven a lot of miles in the last three months, should be cured by now.

Twenty minutes downhill in first gear with your foot on the brakes all the way? You're wondering why the brakes are smelling? Consider yourself fortunate that you still have rotors. The smell may be "normal" but you're asking a lot from a 5500 pound truck.

I don't know if it's possible but I'd pull over a few times to let things cool down. And I wouldn't expect to put too many miles on those pads and rotors.

Thanks for the reply @Trainmaster

So the Jeep Wanglers on the trail don't have this problem simply because they are lighter? Not a different technique?

What about Hill Descent mode? It seems that uses the ABS system to pulse the brakes - which is cooler than riding them I presume. So Hill Descent is a better option in this situation? Note - I tried it but it wouldn't maintain the speed I wanted. I guess I need to learn more about it. I pressed the accelerator to increase to 3 MPH or so but it immediately slowed down again when I took my foot off the pedal. Should I have just kept pressing the accelerator and releasing it? It was a bit jerky when I tried.

The braking system and chassis are the same as a 2014 F-150? So you are saying a F-150 can't crawl downhill without stopping every few minutes to cool down?

Would I have been better in 4L rather than 4H? Does 4L make any change to the engine braking at very slow speeds? Due to the change in gearing from the 4L mode? In 4H there is no engine braking until at least 20MPH in 1st gear, and that was way too fast for this terrain.

Should I combine 4L and Hill Descent? Does that even make sense?

With all these features there has to be better technique that just pulling over to cool down every few minutes, surely?

Thanks

Of course 4L would lessen the effect on the brakes, but you'd be placing the wear and friction on the drivetrain instead. Take your pick. They all require maintenance that is exasperated with severe service.

I have no idea how much protection would be afforded by the on-board electronics. Hopefully someone else can provide that insight. I do know that riding the brakes on any vehicle for 20 minutes will overheat them and cause very quick wear or damage.

It's physics, and all the electronics in the world isn't going to eliminate the heat, friction and wear.

Would a Jeep product or F-150 handle this better? It would definitely handle it differently; perhaps better, perhaps worse. As would a different driver or driving technique. I'd never ride any brakes for 20 minutes. Pulling over to let them cool would just be my "technique". I've burned up and glazed too many brake pads and warped too many rotors doing it any other way.

Of course riding the brakes is not good - that is why I asked in my first post "how to avoid in this specific situation".

You say that all the electronics in the world isn't going to eliminate the heat, friction and wear, so what happens with Hill-Descent mode? Is it overheating the brakes? I doubt it because Ford's own marketing material says that when that mode needs to "cool down" the driver should manage the brakes themselves. Well if the brakes are already overheating or on the verge of overheating at that point Ford would say to park the vehicle instead. So if it is easy on the brakes what is that mode causing wear on? What is the tradeoff?

What are others doing in their Expeditions coming down mountains besides stopping every few minutes?

Does anyone have experience of the capabilities and limitations of Hill Descent mode on a mountain?

Thanks!

My thinking is the current Expeditions are not designed for severe off road duty. Ford references this type of use in marketing materials and pictures, but at the end of the day it is like them rating these vehicles for 9300lb towing capability. Will they do it, yeah, do you want to tow 9300lbs for 1000 miles, not me.

I tow 6600lbs with my 2017 Expy and would not want to tow more than 8,000. My 2017 Expy is no where near the tow vehicle that my diesel Excursion was. But it is sure a lot better at knocking off a very comfortable 1200 mile interstate trip.

So in my opinion the same thing applies to off road, will a 4x4 expy go up and down steep grades on dirt roads, yeah. Will it deal with 6“ of snow covered roads, yup. Is it a vehicle that can compete with an F250 FX4 or Jeep Rubicon in severe off road conditions, not at all. But you would not want to be in either of those vehicles on a 1200 mile 80mph interstate trip.

Thanks for your reply Glenn.

3MPH for 20 minutes is one mile, so I'll rephrase my question: What is the best way to drive slowly downhill for one mile in an Expedition besides stopping every few minutes?

Note - besides the Jeeps, dirt bikes and SXSs I also saw on the trail a Subaru small SUV, a BWM sedan and a couple of Honda Civics. There are also F250s carrying tourists in modified beds - they must be heavier than me. This is not exactly hard-core rock crawling, but I did have to take it slowly going downhill. The picture I gave is representative.

Thanks.

Just because you saw some other light duty 4x4s on the trail, doesn't mean they should be there, certainly not the BMW sedan, Subaru can be the exception to the rule, some Subaru’s are amazing small off road SUVs. A friend of mine has one that he takes off road every week and he has no issues, but his vehicle is designed for that type environment.

In my opinion the brakes in the current Expys are under designed for the size and weight of the vehicle, I have had rotor warp issues multiple times on my 11, 14 and 17, cutting the rotors once and then replacing them eliminates the vibration but doesn't resolve the underlying problem. However, these vehicles do have alot of offsetting qualities, which is why I own 2 and keep buying them.

As others have suggested, you can use low range and stay in the lower gears of low range, but as they also suggested, that moves the work of slowing the vehicle from the brake system to the engine, transmission and transfer case.

For that reason, when I tow, I don't use tow mode, because as designed, it drops gears in a very aggressive fashion when slowing / braking, causing the engine to rev abnormally high (engine braking).

For some improvement, you can try Motorcraft or aftermarket HD pads (I can give you a Motorcraft part #).

Another more agressive (and expensive) solution is to upgrade the braking system with larger Calipers / Rotors / Pads such as Powerstop or Brembo. If you install a properly sized aftermarket system, this will resolve the issue.