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Brakes - the good the bad the ugly

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by vvillovv, Oct 13, 2020.

  1. vvillovv

    vvillovv Senior Member

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    I started to wipe the pins before I thought to snap a shot. Both had the Permatex Ceramic Brake grease on the tips like that lower pin with the rubber seal. Last year I couldn't get that lower pin to move much at all by hand on either side. This year after wiping (what I'm thinking was some extra grease) I got both pins moving freely by hand before I reassembled. I'll be doing more on both sides as time permits, and trying to get a handle on why the inner pad(s) is(are) gettin all kinackered so fast. ;) Did you notice the flaky separation on the edge of the inner pad? I didn't see that until I looked at the pics. In the pic it looks like the pad is wearing wavy, like the wheels not balanced or mounted wrong.
     
    #21 vvillovv, Oct 12, 2021
    Last edited: Oct 12, 2021
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    I think one of the Permatex pin grease swells rubber?

    Try the Toyota stuff (@ChapmanF) has supplied info, up the page)?

    Just FWIW Sil-Glyde Brake Lubricant is what I’ve used a couple of times now on our 2010, no problems.
     
  3. vvillovv

    vvillovv Senior Member

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    I have a list of items I made last week that I need and the lithium glycol soap is on it. I should also top off the reservoirs with (super long 00272-SLLC2 permixed) or (long life 00272-1LLAC-01 undiluted ) , thanks for that info too !!! The list keeps changing here and there as I get deeper into 2021 maintenance.
    I sprayed down the rubber hoses in the engine bay with meguiars m40 rubber/vinyl dressing (use it on the all weather mats too). I found that the hoses under the 12 volt are 3 or 4 times as dirty as the rest of the bay, added to list of chores.
    I took a snap of the engine bay just before I buttoned everything up the other day, but it was dark already and the engine bay pic is not much clearer than my profile avatar, so I didn't bother with the upload. I'll get a shot during the day and post that one.
     
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    I just looked that stuff up again, updated my notes:

    ----
    Toyota recommended caliper pin lube:
    Product Name: Toyota Rubber Grease
    part number: 08887-01206
    Content: Lithium Soap Base Glycol Grease (description on back of tube)
    ----

    McGeorge Toyota Parts in the States has it cheap, ditto for Amayama. The latter is more practical for me in Canada.

    I've had no issues with AGS Sil-Glyde Brake Lubricant though.
     
  5. vvillovv

    vvillovv Senior Member

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    After seeing the color of the grease on the pins last year and this year I'm not worried about the Permatex Ceramic, except the amount I put in the boots and on the pins. I could be wrong but when I finally got the pins loose this year they both had the cone of grease on the end of each pin. The pins were so tight I'm thinking (I haven't concluded yet) the grease was packed in the bottom of the holes, keeping the pins from sliding. I might know more next time I pull the calies.

    Yeah I saw the new name Rubber Grease too. Same part #, Might be what the Lexus team calls it, just for fun, ya know?
    I shop McGeorge and checked out amayama (kinda like seeing toyota in a mirror atoyot or a toy yacht) last time you posted. I'm pretty cheap so I always double check shipping and compare online to local pickup when available or if under time constraints.
    13-oct-2021-engine-bay-meguiars-P1010097.jpg 13-oct-2021-inverter-coolant-tankP1010098.jpg 13-oct-2021-engine-coolant-tankP1010099.jpg 13-oct-2021-trunk-mat-P1010100.jpg
    Engine Bay (dressed a couple days ago)
    Inverter Coolant Tank (low mark)
    Engine Coolant Tank (pic reveals return side overfilled - feed side low - so probably full - which I didn't notice until seeing the pic)
    Trunk Mat (not dressed in several months)

    Still not the best lighting. sometimes I just take what I can get.
    Couldn't see the bottom hoses at all in the morning light.
     
    #25 vvillovv, Oct 13, 2021
    Last edited: Oct 13, 2021
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  6. vvillovv

    vvillovv Senior Member

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    Finally got to the rear brakes today for a full inspection.
    drivers side
    1may-rear-brakes-driver-P1010543.jpg 1may-rear-brakes-driver-P1010545.jpg
    passenger side
    1may-rear-snow-passengre-P1010551.jpg

    drivers side rotor and pads were a bit more knakered than the passenger side. Both sides still have life left at 62 K miles.
    Both inside pads had more meat than the outside pads. driver side was about 3mm inside and 2mm outside (see pic 1) passenger side was roughly 4mm inside and 3mm outside.
    drivers side rotor inside surface was grooved and looked like 3 of the rings of saturn. I was able knock down the rings to almost flat, almost... ( good nough for gov work )... passenger side rotor looked near perfect with full face pad contact both inner and outer sides.
    Slide pins moved easily using only my fingers. Still had original grease that was yellow in color at the pin ends and normal black along the length of the pins, black color was probably from the rubber bushings on both top and bottom pins. all 4 side pins popped out of the bracket and slide back in using one hand while I was shooting a video clip of it with the other hand.

    Driver side emergency brake cable and actuator arm moved easily on the second try. Passenger side seemed harder, but I only messed with it once since it was starting to rain, again !.

    I still don't get how to screw in the caliper piston. It would have made it easier to set the caliper over the pads if I cold have turned them even a 1/.32 's of a turn.

    pic 2 is before I pulled the caliper on the drivers side.
    pic 3 is before I removed the tire on the passenger side.
    I have 10 short video clips I'll try to get merged into one, published and linked below when I get some time to mess around with it.
     
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Shouldn't be too hard; do you have one of these:

    upload_2022-5-2_7-21-2.png

    Search for "brake piston tool".

    You can use something like needle-nose plier tips in a pinch, but it's awkward.

    Check how free-spinning your wheels are when you've put everything back together. There'll be slight drag, but should rotate 2~3 revolutions with a good push. If they're fighting it's likely misaligned piston.
     
    TGrracie, pghyndman and vvillovv like this.
  8. vvillovv

    vvillovv Senior Member

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    I can hear pads on rotors sometimes when I'm gliding in EV at 4 or 5 mph at the beginning of a drive. I can hear the rubbing when it happens up until about 12 mph when it gets drowned out by other road noise.
    I've gotten used to hearing it once in while and I heard on the first drive after messin with the rears brakes yesterday too. But on the second drive I didn't hear any rubbing again, but I'm sure there is something not exactly right with both fronts and rears.
    Thanks for the correct tool for the job posted above. :) It's always nice to have the right tools and the know how to use them before it's absolutely needed and no know how to use them.
    The + cross pattern on the Primes rear caliper pistons were really flat. so flat I wouldn't have even thought to have tried pliers or vice grips to grab hold of them - much less try to turn them - even if I could get a hold of them. But maybe they are not that hard to turn after getting a good grip on um.

    One thing I forgot to mention above is that the bolt hole for rotor removal are a different size on the rears rotors ( which are larger ) than the ones on the front rotors. I got close to have a pair that fit, but the threads were ( I think ) too fine. I have to see if that spec is in my techstream brake job printouts I made before tackling the fronts.
     
    #28 vvillovv, May 2, 2022
    Last edited: May 2, 2022
  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Could be the threaded holes in the rotors were just rusty? AFAIK it's always M8x1.25, that's industry standard, even North American built with imperial bolts.
     
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  10. ttou68

    ttou68 Active Member

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    FYI, if you're experiencing uneven wear brake pads then you should take a look at the hardware your pads rest on.. I often find them dirty/rusty and keep pads from sliding away from rotors after braking... Screenshot_20220502-110237_Chrome.jpeg

    Posted via the PriusChat mobile app.
     
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  11. vvillovv

    vvillovv Senior Member

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    Thanks @ttou68 I had to do major cleaning of the front calipers and the pads were still tight after replacing the pad clips, but they (the fronts) are working much better now than they were before I tore them apart. See original posts in this thread.
    This is the first look I've gotten at the rears and the rears are in a lot better shape at 62 K miles than the fronts were at 36 K miles when I had to replace the front pads and rotors.
     
  12. vvillovv

    vvillovv Senior Member

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    @Mendel Leisk I still have the front OEM rotors and I just checked them. I think what happened is I was able to get the fronts off using M8x1.0 ,, or my rotor removal bolts got moved out of my brakes tool bag. And sure enough I don't have any M8x1.25 s in my spares. The almost fit bolts turn out to be 5/16 course thread, after taking a closer more relaxed look at my spares.
     
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  13. Mendel Leisk

    Mendel Leisk Senior Member

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    If rear pad wear is beveled, particularly the one contacting the caliper piston, I’d suspect misaligned piston, pad backing plate pin riding up on piston face spoke.

    if rear pad wear is just unequal, inside vs outside pad, then caliper pins likely sticking.
     
  14. vvillovv

    vvillovv Senior Member

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    Dang. I've gotta go check again. pad backing plate pin. I remember on one side the inside shim fell off and on the other side the outside shim fell off - after removing the ( pad bracket ), the one with the slide pin holes in it. It's hard to see in the pic https://attachments.priuschat.com/attachment-files/2022/05/221600_1may-rear-brakes-driver-P1010545.jpg the pin just above the black square of the pad.
    It's easier to see in the video clip, it's on the outside pad. And I don't see one on the inside pad, as best as I can remember. I do remember one of the shims fitting around the pin and the other shim not having the cut away for a pin.

    I didn't pull the pads out of the bracket. I pressed the shim tabs to tighten up the two loose shims. Knocked down the ridges on the rotors, cleaned the dirt and reassembled.

    Now I need to take another look. I swear I didn't see anything on the inside pads that the piston would or could hang up on?
     
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    Assuming they’re per 3rd gen (they very likely are), there’s a stubby pin on the rear pad backing plates. It’s about the dimensions of an aspirin tab, except slightly taller. The pin on the piston side is instrumental in the parking brake function: it’s intended to be between the raised spokes of the pattern on face of piston, to prevent the piston rotating when parking brake is applied. If the pin rides up on the spoke, you’ll have constant drag and skewed pressure between pad and rotor, hence beveled pad wear, and a zone on the rotor going rusty, due to lack of contact.

    tactics to ensure proper pin/spoke alignment:

    1. disconnect 12 volt neg cable at outset.
    2. Reassemble with correct pin/spoke alignment.
    3. Depress brake pedal multiple times, get everything seated. Don’t apply parking brake.
    4. Reconnect 12 volt, do a short test drive, going easy on the brakes, and when you get back, apply/release parking brake several times, then raise rear wheels off the ground and check for aforementioned amount of free-spin.
     
    #35 Mendel Leisk, May 2, 2022
    Last edited: May 2, 2022
  16. vvillovv

    vvillovv Senior Member

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    I"ll take detail pics of the piston and inside pad and if I can without removal how the parking brake effects the piston, at my first opportunity. I didn't see the pin or the slot for it. but I wasn't looking for it specifically either.
     
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  17. vvillovv

    vvillovv Senior Member

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    \I did out 70 k oil change a few weeks ago and was planning to pull all the calipers - measure - clean and lube. I only got to the fronts, but this time I had the right pin grease on hand (I think the new name is Toyota Rubber G ) and man what a diff or ance .....

    I tried to get at the rears today, but catching up with sleep time left me with only a few hours of daylight and a backlog of chores. By the time I got the back wheel off all I had time for was the same as a few weeks ago, just general cleaning of outside surfaces.
    Checking back here to read all the notes about the rears.
     
  18. vvillovv

    vvillovv Senior Member

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    Looks like it time to replace the rear brakes. One if the pads is gettin mighty thin. I'm not doing a rotor runout check after cleaning them up, but as I reassembled them yesterday (man it gets dark quick this time of year) just eyeballin the wheel spin looked off just a wee bit.
    I'll know better next time I have the calipers off. -famous last words ....

    adding to notes - since lately it seems the brake pump only turns on when I touch the pedal and not when I open the door.
    How Prius Brake System Works | PriusChat
     
    #38 vvillovv, Oct 24, 2022
    Last edited: Oct 24, 2022
  19. ChapmanF

    ChapmanF Senior Member

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    It's normal for that to depend on how long it's been since the system last ran. The pump runs based on the pressure in the accumulator.

    If you open the driver's door after the car has sat overnight or longer, usually the pressure is down enough that the pump will run. If you open the door, you know, a couple hours after you last drove the car, it probably won't run.
     
  20. farmecologist

    farmecologist Senior Member

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    BTW - being from MN, we get obscene amounts of road salts used on the roads, etc...I have see rotors rusted so bad that they started deteriorating *from inside the rotor air gap*. This was on a severely abused vehicle though.

    When we got the 2012 Prius v wagon a few years ago ( photo on the left ), the brakes were *severely* degraded. As an experiment, I switched to "zinc plated" rotors. Since then, no rust problems whatsoever in the rotor "air gap", etc... While not necessarily needed, I figure since I'm in there, why not use the zinc plated ones. (y) Plus, they look a lot better..and have held up very well.

    Some pics here :

    Hi all, new Prius v owner | Page 3 | PriusChat
     
    #40 farmecologist, Oct 24, 2022
    Last edited: Oct 24, 2022
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