Grabbing Brakes solution

All you need to do is clean them off once in awhile. Find an empty stretch of road, get up to about 40 mph, shift to N, and brake to about 15 mph. Repeat this a few times and it will clean off all of the rust.

Tom

 

Actually aluminum can corrode in the right environment (when chlorides are present aka salt water spray). If you were going to substitute aluminum rotors, you would probably need to resize them to account for the difference in strength. But I think it is also a cost / longevity issue - racing parts don't need to last a long time because they get replaced regularly - production car parts do because the customers get upset at yearly brake replacement.

 

Sometimes grabby brakes indicate that the rear brakes need to be cleaned and adjusted. When I had grabby brakes a rear brake service (just clean and adjust) fixed it. At 120k I have needed only two such cleanings so far and that is the only brake work I have needed.

 

Try caustic...or tomato sauce. We once had a shipment of caustic delivered in the wrong trailer...it had an aluminum tank. It was a sprinkler tank by the time it arrived.

Lasagna leftovers in an aluminum pan soon ate a hole through the pan.

 

5 minutes of "work" vs $300+shipping+real work to install them? Whatever.. it's your money.

 

Forgot only the fronts have discs.

 

Good to know that I'm not the only one with this issue. The dealer acted as though they had never heard of this problem. At 148k, mine started doing this. Finally got it in the dealer when it was raining and they could ride with me to duplicate the issue at 162k. It stopped for a while after they replaced the rear brakes and drums. Now, at 176k, it's been back for the last 5k miles. What a hassle! I agree, Toyota should solve the problem for all of us. That whole "Go 40mph and shift to neutral thing" shouldn't be necessary, but I'll give it a try. Thanks!

 

This is not a good feature of the Prius, especially when you have your boss in the car in the rain who is oogling over the car, then SCREECH! "Oops, sorry, the brakes do that in the rain, boss." Weird?!

 

Hi All,

I rarely have this problem since I put on the flush wheel covers. They were made with .010" aluminum flashing wrapped on the stock trim-rings. The covers prevent rain from blowing in through the wheels onto the disks while the car is parked. Also, helps get the brake temps up in those 7 to 0 mph stopings that the friction brakes actually are used for.

 

be careful with flush wheel covers. brakes do need some type of cooling. especially going downhill on a hot day. without cooling, brakes fade and the pads heat up to an unbelievable point.

 

Fundamentally the brake discs get rusty because the water never gets properly wiped off, or come up to enough temperature for it to boil off.

This is going to be very do-as-I-say-not-as-I-do, but if it bothers you, just make sure you rinse the discs with plain water after you've been driving on salted roads, or use the Neutral trick pre-emptively to wipe off the water.

As donee says, the friction brakes are normally only used for a tiny part of braking, most of it being done through regenerative braking. I estimate that you need less than two metres to stop at 7 mph, which is less than one full rotation of the wheels (rolling circumference is approximately two metres, slightly less for Gen 2, slightly more for Gen 3).

I think I read somewhere that the car does bring the brake pads up to just skimming the discs when using regen braking, to reduce the time to apply them and to wipe the discs a bit, but I can't find a reference in Gen 2's service manual or Gen 3's New Car Features guide. It's possible I imagined it or was thinking of a different car.

The brakes do have to be designed to the maximum potential braking force, which is emergency braking to a stop from over 100mph. The front discs are large and dual-ventilated for this reason - larger discs don't actually give a larger contact area (the pads are the same size), it's just to make sure they don't overheat. The pad material also has to be fairly heat-resistant - for normal braking I think a softer, less grabby material could have been used but it has to stand up to the worst-case scenario I mentioned earlier.

 

Hate to barge in, but isn't this a permanent fix? I mean from the POV that we own lots of products and appliances that need periodic maintenance or things done to them once in a while. From my way of thinking if you live in conditions that happen to promote rust and the grabby brake syndrome..(GBS) then I'd much rather deal with it with a relatively easy occasional maintenance maneuver than total rotor replacement.

I mean if you do clean them off what is the time period inbetween reoccurence of symptoms? If all I have to do is brake hard a couple of times in the manner prescribed, once a month during the winter and rainy times...I'm not going to sweat it. That's assuming I'd get at least a few weeks of relatively normal braking behavior. If it occurs more rapidly than that, I'd consider the rotor replacement, upgrade.

I live in Oregon, so rust and braking reality in wet conditions is a real concern.

 

I'm convinced this is a brake pad formulation issue. i don't think any of us heard much about this problem until 2006 or 7 (My 2005 Prius never had this issue, the 2008 does).Before 07, there were lots of complaints about the brakes needing to long to catch in cold and/or wet weather. Just a guess, but could Toyota have changed the pad formulation to work better cold, and in the process caused them to be grabby?

 

Hi All,

Welp, its not mountainous here in Chicagoland, so the battery rarely gets fully charged on a down-hill run, which would then require the fricition brakes. And my friction brakes were starting to develop pitting. With the covers this issue is resolved, the brake temps are getting just high enough to keep the water driven out of the metal grain. In fact, the only places in my driving when the battery gets up to 7 bars on a few down ramps into stop lights. And then the battery is still one bar short from fully charged.

Someone could develop a flush wheel cover with a hole in the center. The hole could be sized to give good ventilation. The hole in the middle would have minimum air-drag as the edges do not rotate at the same speed as the slots on the outside of the typical hub-cap. The hole in the center of the cap also avoids rain blowing directly onto the disks (hitting the hub and hopefully dripping away from the disks).

If you live in a mountanous area , yea, you do not want to have the wheels completely blocked off, as down grade the battery will fully charge, and then the car will use the friction brakes. In fact on Ecomodder I cautioned a guy in Leadville, CO about doing flush wheel covers on his non-hybrid car. Apparently, this is one of the most mountainous areas in the US.

But for the rest of us, the flush wheel cover is a good solution, and they pop right off easily for the times when mountainous roads are to be traversed. Before doing the flush wheel covers I sampled my disk temps in mid-summer weather after the drive home. I stuck my nuckle through the gap in the wheel and brought it closer and closer to the disk. Feeling very little temp I brount my nuckle in contact with the disk - it was maybe 100 F. The same test with a traditional car and one would not want to bring a nuckle any closer than 1/4 inch from a brake disk. Disk brakes on standard cars easily run at 250 F in normal sedate, civilian secondary road driving. So, its a little rediculous to caution someone to avoid 130 F (maybe) on ones brakes, rather than 100 F, as is the case here in Chicagoland secondary road travel in the Prius.

If one wanted to be cautious about this, one could have the aluminum flashing black-anodized to be as close to radiationally transparent as possible.

In the winter, its also probable that the wheel bearing greese is coming up to temp quicker without all that 3 F air flow over the brake disk (heat sink). And the aero advantages are are significant as well - about 4 percent as measured by various people on ecomodder.

Narf, hmm...Wet, rusty brakes in my 06 are plenty grabby. One of the motivations to do the flush hub caps.

 

I also experience this when the I first washed the car, what a surprise, but that wasn't the only time. I have experienced grabbing brakes in perfectly dry weather. I read on this forum on another thread that the easiet way to reset the brakes is to put it back into park and apply the parking brakes, you don't need to turn off the car just reset the brakes. It works every time for me. sometimes when I feel that the brakes are "grabby" I just keep my foot on the brake pedal until I feel the pressure reduce then everything is fine