New brakes, huge mileage drop

welcome!
sounds like they might be rubbing. i've never heard of a big drop with new brakes. otoh, morning rubber might be something else.

feel the wheels after driving awhile to see if one is hotter than the others.

go down a hill in neutral to see if it glides freely.

 

Especially the rears. Report back if the rears are hot, I'll warm up me typing fingers in the interim lol.

Oh and: was it a Toyota dealership, or?

 

Did you ever figure it out, I am having the exact same issue on my 2010 Prius and no one, including my local Toyota Dealership can figure it out?

 

sounds like something was rubbing

 

Not yet, I think you have commented on my original posting a few times.... I cannot figure out why the regen brake system is engaging now as soon as I let off the accelerator and why it would be engaging so much to slow the car down when I am going DOWN hill. If this is 'normal', my car never did this prior to the brake change last week, and I hate it.

 

For example, there is a very steep, long hill that I have taken at least 100 times. Prior to last week, I could be going 65 MPH at the top of the hill and let off the accelerator and by the time I would be at the bottom of the hill, I would be going 78-80 MPH. I did the same thing today to see what would happen... I was at 65 MPH at the top, let off the accelerator and at the bottom of the hill I was going 66 MPH, the whole time the regen brake system was engaged.

 

With your foot off the pedals, there will be some regen... but I suspect that the additional braking force you feel is not coming from the regenerative system.

I've read of it happening before- a shop replaces the pads and misses a step or two, and the pads cannot "relax" all the way, so they are causing constant friction. Not good.

 

But the friction/resistance goes away immediately in Neutral and immediately returns as soon as the car is back in Drive or B gear, I would agree with you if the resistance was present in Neutral ??? Thoughts?

 

a dealership might have a way to measure regen with tech stream, idk. but to me, it sounds like your car is normal now, and wasn't before. keep in mind, regen braking has nothing to do with the brakes, and everything to do with the tranny. that's where the magic happens, with the gas and brake pedals as electronic facilitators

 

If there are two things dragging but only one (regenerative braking) can be controlled by the driver, it could account for what you are experiencing.

 

True, I do not think there are 2 issues, initially I thought something with the brake pads/rotors was causing the issue. Either the regen brake system is always engaged and my car was not working correctly until last week, or something is wrong with the regen brake system causing it to be 'stuck on' all the time.

 

I think your brake cylinder is stuck. The new brake pads are thicker than the old ones, so the piston position of the cylinder in the standby state is different. It is recommended that you disassemble the cylinder piston and check that there is dirt. Clean up, if there is rust, use sandpaper to deal with it, and apply a little grease before putting it back.
Although you did not step on the brake, if the piston of the sub-cylinder did not return, it is still in the brake state, and you smell the burnt smell is an obvious clue.
Good luck.

 

Feel all your wheels after a drive; do any feel unusually hot?

Raise the rear (front wheels chocked) and try spinning the wheels; they should go 2~3 revolutions with a good push. If they’ve been misassembled (which is very easy to do) they’ll drag, stop immediately.

 

which part of the wheel?

 

^ This. The regen braking system doesn't make that smell.

There was one time I drove home from a Ford dealer in a Bronco II that I had, and it drove like a dog for the mile and half or so home, and when I got out, I did not have to 'feel' any wheel; I could feel my leg roasting inside my pant leg as I walked past the wheel.

 

Middle is best, directly bolted to brake disk.

 

May go without saying, but bring hand to wheel slowly.

If you feel broiled from a few inches away, abort the maneuver before touching.

 

When I've had problems with stuck pads I've bought something like this specially for rotors temperature.