The ONLY problem we have had is to replace the brakes more times than we feel should be necessary. This seems to correspond with driving in the mountains of NC/TN. Every time we have had to replace the brakes soon after returning from a trip. We downshift as often as possible to avoid using the brakes. We do not ride the brakes. What else can we do or is this a problem others have experienced? The car has 180,000 miles and we do love it but thinking about trading it in if we can get more than the $6000 we have been offered for it.

 

Putting more stress in the transmission which costs astronomical to replace than replace brakes is diabolical

 

You do realize that many cars on the road automatically downshift when going down a hill. Including the RX. So I don't think doing what the OP said is bad for the transmission.

 

How often?

 

There's a difference between manually downshifting and automatically downshifting.

 

lol what

 

you auto shifter can downshift manually

 

it's the same computer executing the same downshift in exactly the same way regardless of who commands it

 

So in this case, manually downshifting your "AUTO" shifter equates the wear it would make if your car downshifted by itself?

 

No, there is not. The transmission ends up in the exact same gear.

 

You have not mentioned front or rear. Are your sliding pins binding? Cheap pads vs good pads?
I highly recommend Akebono pads, they cost same as OEM. For sliding pins, silicone grease.

 

Jeez, don't trade it in for something so easy to fix. There's a lot of brake upgrades for these, 2021-2025 Sienna front calipers & rotors (36mm rotor width vs. 28mm to hold more heat), 2020+ Highlander (345mm front rotor vs. 328mm front) or GR Corolla 4 pots with the adapter bracket sold by 350phi (355 front rotor w/ beefy 4 pots). The brakes on these are a little bit undersized for such a heavy vehicle, but mine still last a long time. Although, I think some good rotors and pads with a higher rating (Maybe GG / GH) would solve these issues.

 

The front brake discs on the 2021+ Sienna are also 328mm, what's the point?
The information regarding the disc thickness of 36mm is incorrect. The thickness is the same, 28mm.

The Highlander has a diameter of 340mm. The thickness is the same, 28mm.

 

The 2021+ Sienna still has 328mm rotors, but their rotor width is 34mm vs. 28mm. You need the correct Sienna caliper to run those wider rotors, but they can fit behind 17 and 18" wheels. HL 2020+ requires 18" wheels as the 340mm rotor w/ caliper combination is too large to fit under a 17".

Also, both of those calipers require drilling the knuckle hole from 12mm to 14mm along with the correct M14-1.5 x4 bolts, so not a direct fit. Although, probably worthwhile if you're burning through front brakes quickly on one of these

 

The OP has never said how many miles between brakes jobs they consider to be too frequent. Or who is doing the brake jobs. Just that it appears to be after driving in the mountains. Without knowing how long their brakes actually last, we don't know if they have a valid complaint or if it is normal wear and they have unreasonable expectations about brake pad life expectancy. They have yet to respond to any of the above comments.