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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    To start with my brakes were ugly at 36k - read more in Gen4 main here 2018 Prius Brake problem 35K miles | Page 3 | PriusChat - I've since read all the posts in the thread and want to thank to members that posted before I did for all the technical data I've since used to compare with my experiences.

    I posted to the thread not knowing how ugly my front brakes had gotten. Being the thread was in the Gen4 section and I was posting a lot, I had second thoughts that I may be hijacking the OP's thread. So I'm starting this thread in the Prime section, to hopefully keep things here at PC cleaner.

    This older post in Calling a spade a spade on 2 Sept 2020 I believe is my first post referencing our Primes brakes. So I probably first noticed them in Aug as I didn't drive the car at all in May June or July and possibly March and April too.
    Calling a spade a spade | Page 2 | PriusChat

    My first post here is a general question concerning caliper slide pins. But before I ask about the pins I'd also like to include OE vs aftermarket components - caliper bracket anti-rattle clip reuse replace -- rotor wear, anything special to lookout for --- and hints to help the driver determine possible brake problems.

    Onto the caliper slide pins. My question is --
    Does the OE Glycol Soap grease actually make the bottom slide pin slide more easily?
    I'm certain it will make the upper pin slide easier, even if it's already been used on that pin during prior maint.
    And, the recommended caliper overhaul includes replacing the bottom slide pins rubber seal. Does everyone
    either reuse or replace that seal? And also, is it less important that the bottom slide pin actually slide freely with or without the seal, as opposed to it possibly being reused as the top slide pin? Thoughts!

    And finally does glycol soap look dark reddish almost jet black? and what happens when pad shim grease is used on the slide pins? Does the factory use glycol soap on the slide pins or is it called glycol soap for a different reason?

    edit: 07 sec youtube clip from "My Cousin Vinny"
     
    #1 vvillovv, Oct 13, 2020
    Last edited: Oct 13, 2020
  2. ChapmanF

    ChapmanF Senior Member

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    A grease is generally some kind of oil, thickened with some kind of glop; often the glop is chemically a soap.

    The Toyota 08887-01206 grease is a glycol-based oil, with a lithium soap used to thicken it.

    It is kind of a clear pinkish red out of the tube, with a smell a little bit like old basement.

    It is the specified grease for the slide pins and their boots, and for the piston and its boot and seal (in case you ever overhaul the caliper to that degree). If you buy the overhaul rubber kit (all the rubber parts and a few other miscellaneous bits to do two calipers), the kit includes a little packet of the red grease.

    If it looks dark black, it could be old and cooked, or darkened by rust, or somebody before you might have mixed it with a different grease. Grease mixing is usually not recommended. If that happened, the pins and bores can be cleaned out with a solvent and a rag or swab, so you can apply clean replacement unmixed grease.
     
  3. vvillovv

    vvillovv Senior Member

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    Thanks Chap - I've been researching which Toyota greases are which. I've been using light purple Permatex 24125 Ceramic Caliper Grease for a few years and used that when replacing the pins. Although the bottom pins with the rubber seals near the tips are still very tight and I'm going to recheck them.

    While searching around yesterday I stumbled upon the youtube channel Toyota Complete Maintenance, which address everything I asked about in my OP above


    the good
    after getting the new pads and rotors installed on the fronts the prime is rolling freely again much like - if not exactly like new again.
     
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  4. vvillovv

    vvillovv Senior Member

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    the bad
    dealer quote using value parts front pads and rotors at 500
    sounds close to 400 labor.
    That was the one that actually give a quote by phone. thanks
     
    #4 vvillovv, Oct 14, 2020
    Last edited: Oct 14, 2020
  5. Mendel Leisk

    Mendel Leisk Sand Pounder

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    NY (state?) is rust belt. Maybe get into bi-yearly brake service.
     
  6. vvillovv

    vvillovv Senior Member

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    at very least it's now got the right grease of the slide pins. I'm glad I was able to get to it before the snow flies.,,, Only 3 service items left and crossing my fingers I can get the car on a nice day or two and finish up the odds and ends.

    I haven't had to start maintenance on a car this early in the cars life other than oil change. But I'm really glad I caught it before it got worse.

    Bi Yearly sounds about right to me too.
     
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  7. vvillovv

    vvillovv Senior Member

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  8. vvillovv

    vvillovv Senior Member

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    Since a broke a wheel stud (grrrrrr) while rotating the tires, I had to pull one of the front calibers to replace the the wheel lug bolt.
    Only 15k miles since the brake job and that one rotor has - indications - of 1/3 of the rotors inside face not making solid contact with the pad.A little strip around the hub and a larger strip around the outside of the rotor. I doubt any shop would bat an eye at the condition the brakes are in at present, so I'm not pressed into having to do anything right away.
    Looks like I'll be doing a caliper cylinder rebuild this year. If I can't get the pad/rotor contact any better than it already is I'll be looking at new calipers, eventually. Pads still look close to new and I'd like to keep it that way this time.:)
     
  9. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Who did the brake job? Is that a rear brake?

    If so I’m thinking misaligned piston: it HAS to have cross pattern on its face oriented like an “X”, so pin on inner pad backing plate is BETWEEN caliper face raised spokes, AND solidly seated thus.

    A clue would be excessive rear wheel drag; wheel should spin 2-3 revs easily with a good push.


    (All the squeaking is my shoes on the concrete I think, not the wheel anyway.)

    repair manual info attached.
     

    Attached Files:

    #9 Mendel Leisk, Oct 5, 2021
    Last edited: Oct 5, 2021
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  10. vvillovv

    vvillovv Senior Member

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    Thanks for the video, I'll have to see if my rear wheels even come close to spinning like that. ;)
    I've even been thinking about wheel barrings off and on in my spare time.
    I did the front rotors and pads last Nov. at 30k miles. Here are the pics of the knackered parts I replaced. ;) Oil change door missing plastic fastener | PriusChat
    I haven't touched or even looked at the inside of the rotors in the back yet. But I'm not getting any indication anything is wrong with them yet, either. I'm sure they're not in as good a shape as the front pads and rotors and I'm keeping my fingers crossed about it as I want to square away the fronts before I think about tackling the rears if they need attention.
     
  11. Mendel Leisk

    Mendel Leisk Sand Pounder

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    So the "rusty 1/3 of inside face of rotor" is front brakes?
     
  12. vvillovv

    vvillovv Senior Member

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    Front it is. Rhymes with fronk like in my ole 65 VW (1200 cc / extractor chrome exhaust, rear flared fenders and chrome reverse wheels) baja bug. Yea, I saw that 58 manual excerpt too and it brought me way back in time...
    Not rusty yet.
    Can definitively see inner pad is not making full contact on rotors inside / engine side face, both near the center /wheel hub (small circle of non contact area) and on the outer circumference (larger circle of non contact area) of the rotor. I already buffed it out with 80 grit, but I'm sure it's still noticeable although fainter than before. When I pull it again to do the cylinders I'll try to at least get some decent pics of both sides. I'm always rushing to get tools and trash (away after dark) and sometimes in the rain.
     
    #12 vvillovv, Oct 5, 2021
    Last edited: Oct 5, 2021
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  13. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Yeah on REAR brakes, if the aforementioned piston X pattern is misoriented, say like + , then the spoke of the cross is bearing on the back-of-pad pin (instead of two of the spokes straddling the pin), which messes everything up, causes constant drag and uneven contact. You get beveled pad wear and a zone of the rotor having near-nil pad contact, and accordingly getting rusty.

    your issue is front brake, but symptoms are similar, so maybe somehow cause is similar? Something causing uneven pressure.
     
  14. vvillovv

    vvillovv Senior Member

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    This will be my first cylinder rebuild, since I'd just get new aftermarket calipers when needed in the past. Nothing special about the cars I've previously owned except that first Vdub.
    Given the condition of the rotors and pads I had to replace last year, plus the gunk I found on the slide pins, I'm not surprised if the caliper pistons are a bit dirty too. Shouldn't the part be called a caliper piston rebuild kit?
     
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  15. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Never opened up pistons, beyond my pay scale lol.
     
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  16. ChapmanF

    ChapmanF Senior Member

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    There's a caliper rebuild kit, includes all the rubbery bits, and odds and ends like the banjo bolt gasket, for doing both sides' calipers (one kit does both fronts, one kit does both rears). Includes a little packet of the proper lithium soap based glycol grease.

    Does not include pistons themselves. If a piston is actually trashed, it can be bought a la carte.
     
  17. vvillovv

    vvillovv Senior Member

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    Thanks Chap I'll be inspecting the calipers a lot closer before I commit. I was more focused on replacing the broken wheel lug bolt and the rotor was a side chore since I had it off. I'll take notes when I get the other side apart.
     
  18. vvillovv

    vvillovv Senior Member

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    I only got at the Drivers side the other afternoon and made some progress in that side and got some pics of the Pass side also. Three things are starting to get my attention. 1 The Mag is a tight fit on the hub, easy to mount the wheel off center. I'm starting to snug the lugs all the way down by hand and wiggle the wheel as it gets near bottoming out. I've already broken one hub bolt mounting a wheel. 2 The slide pins were too tight to pull them by hand. Although I thought I used the right amount of grease last year, I'm thinking I put too much on. After wiping them both they moved much easier than they did last year during reassembly. And I think there is still plenty of clean grease in the pin holes. 3 I'm still not sure why the Drivers side Inner pad is wearing faster and not making full contact with the rotor, more so than the outer pad. Could it be too much grease on the pins making them way to tight

    driver side
    10cot2021-wheelDriSide1010069.jpg 10cot2021-Dri-Bot-SlidePin1010084.jpg 10cot2021-Dri-Top-SlidePin1010088.jpg 10cot2021-Dri-Brak-Asembly1010073.jpg 10cot2021-Dri-caliber1010079.jpg 10cot2021-Dri-hub1010078.jpg 10cot2021-Dri-pads1010080.jpg 10cot2021-Dri-rotor1010090.jpg
     
  19. vvillovv

    vvillovv Senior Member

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    passenger side I didn't have time to get to
    10cot2021-wheelPas1010092.jpg 10cot2021-Pas-2rotor1010093.jpg 10cot2021-Pas-1rotor1010094.jpg 10cot2021-Pas-rotor1010095.jpg
     
  20. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Seems like something's hiding-in-plain-sight.You've got uneven pressure on the rotor. Pins look pretty dry, what was the grease you used?
     
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