Mysterious whine after driving in heavy freezing rain (recording)

While now is not the best time to investigate, but when was the last brake inspection?

How many miles on your Prius?

Any history of accidents or damage?

While not a mechanic, do you feel comfortable taking off a wheel and investigating?

Keep us posted .

 

Perhaps check the wheel wells for ice accumulation. Slush tends to pack in and then freeze, and can make odd sounds when rubbing up against the tires.

 

Definitely has a metal to metal sound to it.

Definitely worth pulling off the wheels and checking it out.

2 sets of pads by 90 k miles? I would be checking the alignment of all components and increase the frequency of inspection as that is not normal.

While I live in a non snowy area and have 170 k miles on the original pads with about 7 mm life left up front and 5-6 mm in the back, there are plenty of those in the salt belts that have longer pad life. Something to me doesn’t seem right.

Merry Christmas .

 

I have that going on my Prius also. Sounds like the capiler pins need a fresh anti seize lube. One or both pin has seized and pad(s) are not fully disengaging from the rotor so the pad(s) is still making contact.

Mine will come and go if I hit a bump, mash harder on the brakes or small pot holes on the road at fast speeds. Plan to reapply anti seize on my pins also.

OR it could be that the warning low brake pad clips are making contact and that sound indicates replace them now.

 

Lucky you, les schab said I had 6 mm left on all 4s with 87k driven after rotation.

 

Who did the replacement? A competent dealership, or? Even with a dealership, if they don't do a lot of Prius (3rd gen and onward, with rear disc brakes), they might miss this:

The rear brakes are a poor design, in that it's absolute necessity to get the caliper piston rotated to a certain orientation, and easy as pie to not do it, and apart from a bit of vague reference in the Repair Manual, there's not much warning.

If the piston is mis-oriented, symptoms will be pronounced drag (and maybe reduced mpg?), hot rear wheels, fast/uneven (extremely beveled) brake pad wear, scored rotors. With mis-oriented piston you're basically applying terrifically unbalanced pressure on the brake pad: pushing hard on the outer edge, and next to nothing on the inner edge.

 

Based on your above post, sounds like we have our first job at the next meet up

 

Dam the next meet up needs to happen soon because mine has been going on since last month. But this needs to be done tomorrow or next week because paid holidays means no work next Monday and Tuesday so that's the only time I can get to it, unless the meet up is before the end of January.

 

I’m around and don’t have much going on .

Maybe you’ll find yourself down this way.

Let me know.

 

You know where the bar is now, and it’s not very high.

If you have basic tools you can tackle this job.

What year is your prius? I ask because I’m not sure when they changed the back piston, but at the last Bay Area meet up there was a Prius v that did not have the alignment piston @Mendel Leisk describes. It might have been at the mid cycle refresh, or not at all. Something to be aware of though.

Maybe Mendel will post a pic so you can see what he means.

Keep us posted .

 

Just remember there is a jack point in the center of the rear in front of the spare tire area. The pinch welds are acceptable, but the back jack point gets both wheels at once.

That’s what I use and then some jack stands.

What area of Vermont are you located? There are some members in here that might be able to help if we have a better idea of your whereabouts .

Good luck and keep us posted .

 

The above is an illustration in an excerpt from the Repair Manual, the section on front and rear brake maintenance (which I'll attach). It shows the correct orientation of piston, so that the stubby pin on back of inner pad falls between spokes.

You want to get everything well seated in that orientation, to that end: when everything's assembled, do multiple brake pedal presses, take the car for a short test drive, gently apply brakes, and finally raise the rear once more, and test-spin the wheels. They won't be exactly free-spinning, due to disk brake slight drag, but they should easilly spin a revolution or two, with just a whisper of drag.

Only then apply parking brake. I'm not 100 clear on this, but I'm pretty sure every application of parking brake attempts to rotate the piston, and that's basically the function of the pin locked between piston spokes, to prevent this. So delay parking brake use until the whole thing is well seated.

The one caution with Prius brakes: disconnect the 12 volt negative cable at the outset, and reconnect only when everything is completely buttoned up. Keep in mind to keep the hatch from completely latching, say lay a glove over it, to prevent the need to crawl through the car to release hatch.

 

@m.wynn is within 3 hours and @mmmodem who just moved out there is within the same time span, but not sure of his setup .

@m.wynn has a very nice setup right along the Hudson (you can see it in his avatar) and a great garage (which includes VXDiag capabilities).

 

I don't even put safety stands on those #$*$!@ pinch weld locations: they are flimsy knife edges. If you look at the supplied scissor jack, it's cradle is designed to cup around those pinch welds, the bearing point is actually behind, on the car body, and it's really not strong enough, I noted it dimpled slightly, when I used the scissor jack with a flat tire.

I would raise the rear with a floor jack on the aforementioned rear-central jacking point (the little steel "inverted mesa", indicated in Owner's Manual), and then settle it onto safety stands, at the two reinforced plates zones, just inboard of the pinch weld loc's.

Here I've circled the jacking point and the two safety stand points I use:



Also, maybe goes without saying: use kosher/heavy wheel chocks, fore and aft of each front wheel. And half-loosen rear wheel lug nuts prior to jacking.