Hi all.. While getting my transaxle fluid changed at 60k miles the tech noted that my rotors were "gummy" and needed turned. I spend winters in the mountains and have daily battery full, all friction braking down the mountain , could the "gummy"ness be due to the mountain use? has anyone else experienced this? Is there a replacement rotor / brake pads that would perform better in these extreme conditions? thanks!
I would strongly recommend the use of B mode going down long hills, if you are not doing so already. Eventually the car will do the switch itself as a protective measure when the battery gets overfull. If you know the terrain, it is better to use B mode well before it is needed, if the hill is a long one. That will save on brake wear, at the expense of a bit of engine RPMs. Heater on full, windows open if need be, to further use some of the excess energy. Most here see reduced brake wear compared to normal cars, so your situation may very well be due to hard braking.
thanks for the reply, but I'm not sure if you have experienced the scenario I drive on a daily basis in the winter based on your reply. on a 3000' mountain descent the battery gets to max level within 1000-1500' and it goes into firing the spark plugs mode to burn off charge and uses friction braking primarily since there isn't anywhere to put the charge. B mode helps, but on a 6% + grade it doesn't do more than keep it from gaining speed. I am curious if other mountain drivers have had the same thing happen to their rotors.
I go from sea level to 3300' and back down on my travels on Haleakala, so I know the situation. I wish I had a drogue chute to slow things down. I am in B mode before the battery is full. Windows down for drag, A/C on to use power. It is not a slow road, so braking is not so demanding as what you may be experiencing. I don't think that the Prius was designed for Pikes Peak sorts of roads, and will burn up the brake pads perhaps even faster than a standard car.
Your tech may also just be looking for work to charge you for. If the rotors aren't worn thinner than spec and you don't feel any irregularities in your braking, they are most likely OK. Ask him what "gummy" rotors are. Sounds like a made up term when it comes to car brakes.
+1 on this. Particularly since there is no need to go anywhere near the brakes while changing the transmission fluid. If you're friction braking is working correctly, without any undue pulsations for example, then it's quite possible that there is nothing with your rotors.
You have some misunderstandings of how "B" mode works and also the details of the energy "burn off". By entering "B" mode at the beginning of the decent you delay the onset of the need for friction braking and so conserve your brake pads. It does this by allowing the engine to continue to spin without fuel injection (even when you cant hear it revving) and so deliberately wasting some energy. When the traction battery is eventually too full to take anymore charge then you may hear the engine rev's greatly increase. And though it will do this whether or not you're in "B" mode, the onset of this state will be delayed by using "B" mode from the start, that is the point. Now this state where the engine begins revving (despite you not requiring power or even braking) is NOT caused by "firing the spark plugs mode to burn off charge". The spark plugs are not fired and no fuel is even inject during this phase. Instead the electric motor MG1 is merely spinning the engine for no reason other to dump battery energy. Think of it like sitting in a conventional car with the fuel pump disconnected and your foot on the clutch and just cranking the engine for no other reason than to flatten the battery.
actually I get to battery full mode at a farther point down the mountain descent when I don't use b mode and go as slow as possible (road friction instead of regen). I read the spark plug firing this on this site many years ago, thanks for the clarification, either way it doesn't change my situation. Can someone recommend an aftermarket rotor so I don't burn up a stock rotor set again? uart there is another fill point for the tranaxle fluid on the wheel side which is much easier to get to than the fill plug on the front of it.
Nothing you've posted indicates that you burned up your rotors. The "gummy rotor" comment your "tech" made is nonsense. To answer your question, if you want significantly better rotors, than stock you need larger rotors. That's a big job.
I felt a new rotor and my rotor, there is a difference and it does have a gummy quality and a different color to it. The shop I was at is a large contributor to the prius community, but i didn't state that so of course the great prius can't possibly have an issue.
Rotors that have been used hard will have a different color, that's normal. The rotor "gummy quality" is most likely pad material that has transferred to the rotors. You should be able to find better quality pads in the aftermarket.
