Brake Burning Smell after steep downhill

Its so easy. Use mode B, not the brakes. You will not have a burning smell, again

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i would take a look at the pads and rotors just to be safe.

as for wearing the engine, your thinking of the olden days when we used to downshift and use the engine to brake in a gasser.
in a prius, it is designed for this, and will not cause any wear

 

With other cars I use compression, with Prius I use mode B

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It's not the answer you wanted to hear, but everything you describe screams for the use of B, and don't think for a minute that engine braking hurts anything. Your engine will be perfectly safe and happy, spinning with no load and plenty of motor oil splashing around inside. You will be burning little or no fuel, and if you pay attention, you'll notice the engine temperature can drop quite a bit while engine-braking. P.S., it's normal for brakes to smell when they get very hot, but you should try not to let that happen. If they develop a surface glaze, they won't stop the car properly and will need to be replaced.

 

i think after a burning smell, all safety systems should be checked. how many miles on her?

 

I agree. Living in Colorado, I do plenty of mountain driving, rarely use "B", and have never have had a burning smell. How long and steep are the downhills where you experience this? Does it happen only when you have reached full bars or other times as well? Lubricating the pins might not solve it but seems like a worthwhile maintenance and troubleshooting step in your case.

 

As you know, the Prius relies upon regen braking to carry most of the braking load UNTIL the traction battery becomes charged to the point where all bars appear on the traction battery state of charge gauge. At that point, the friction brakes are relied upon.

Apparently you are applying the friction brakes to the point where they are overheating and causing that burning smell.

Instead of doing that, you should shift into B once you find that the traction battery SOC gauge shows all bars. That will help to slow down the car without causing undue strain on the brakes. The use of B is not harmful to the engine or the transaxle.

I travel to Lake Tahoe periodically, and use this approach when descending from 7,700 ft. elevation. It works well and the Prius brakes are not stressed via this approach.

 

You need slotted drilled metallic brakes, you’ll be a certified racer

 

How long are these downhills? If it's just a half-mile at most you should be ok, bu if they are serious "mountains" I'd for sure be using B. If and when it flattens out enough during your descent switch to D, before going to the gas. When it steepens enough that you're going to the brake, switch back to B.

Here I use B for coming down Mount Seymour, that's about it locally.

 

I see your back to the old avatar staple .

 

Take our Prius I to high elevations all the time (I’m in Colorado). Brake smell is so frequent, as a lot of folks don’t know what engine braking is. Prius is easy with the B mode. Our Subaru, on the other hand, I toss it in manual mode and ride 3rd gear most the way.

As for the smell of your car - it’s fine.
Have the brakes been acting normal since?
If yes - it’s fine. They get hot when used heavily....which is normal

 

If I were you I would get the brakes checked, it sounds like something is hanging up.
Are you on your original brakes?

 

Check the wheel temperature when it smells

I would guess you have a brake unbalance. So you mostly brake with one wheel instead of 4, so that gets hotter sooner

Be careful not to get burned

 

Please explain this process, how one can notice engine temp has gone down.

 

I watch engine temperature using a multi-function ScanGauge plugged into the diagnostic port, but if you are running your heater while in B you can notice that heat from the air vents will become cooler after a descent that lasts for 2 or 3 minutes.

 

The engine is spinning due to MG1 but not running to burn gas and produce heat but the coolant and oil are circulating through the engine removing heat.

 

This is defective logic.

Until the HV battery is fully charged, the regen drag can provide most of the braking.
After that, letting it use the engine does NOT "stress" the engine. It turns well below the design maximum speed and uses virtually no fuel in the process.

Have you ever seen a semi stopped on a long downhill with one of the tires ON FIRE ??
This might happen to you if you don't re-think this.
You are doing it entirely WRONG.

But if you insist, a complete rebuild of the brakes would be needed: pads, calipers and vented rotors.
After that, you might need to add some brake cooling ducts too.