Breaks inspection: my observations and surprises.

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Former Member 68813, Nov 30, 2014.

  1. Former Member 68813

    Former Member 68813 Senior Member

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    My car has 44,000 miles (at least 30,000 of them city driving) and 50 months.

    I've heard a lot here how Prius is easy on breaks and requires no brakes in at least of 100,000 miles.
    On the other hand, I heard some people run into brake problems (usually rear ones) at low miles. I also had brake problems (grinding noise) in my RAV4 at low milage of 50,000. There was uneven pad wear and stuck or near stuck slide pins with what appeared insufficient amount of slider grease from the factory.

    So, decided to crack open the brakes in prius at the time of wheel rotation after the usual precautions (disconnected 12V battery and car resting overnight).

    Here are my observations and surprises:

    0. Wheel lugnuts were very tight 5,000 miles after a dealership installed new tires (no exactly surprise here).
    1. There was uneven pad wear at each wheel with more wear in outside pads. Front: 7mm/9mm. Rear: 6mm/9mm.
    2. Rear pads had abnormal wear pattern with the wear surface not parallel to the backing plate.
    3. 3 of the 4 front slider pins were hard to move and only had grease at the deeper end, and quite dry on the rubber seal end.
    4. The factory slider pin grease is yellowish, heavy and clearly different from the rubber/glycol grease Toyota specifies in the factory manual (pink and soft).
    5. The front lower pins had no rubber bushing in the grove (omission?), unlike other toyota cars.
    6. The rear pins had different construction with black coating (moly?) . Smallish amounts of grease, but not stuck.
    7. One needs the brake caliper tool to put the rear caliper back even without replacing pads.
    8. The front OEM pads were made by Advics and the back ones by Akebano. Both had low-metalic composition (either organic or ceramic, hard to tell).
    8. I didn't pump brakes with 12V disconnected. I simply connected the 12V and let the electric pump pressurize the system when door opened (it took longer that usual). No codes. Normal brake function.

    Uneven rear pads (I know, the picture sucks):
    IMG_20141130_115423.jpg

    Front pins. Right: upper one cleaned and covered with rubber grease. Left: lower one with factory grease.
    IMG_20141130_110414.jpg

    Brake tool. $5.99 at HF (was $4.99 just a week ago):
    IMG_20141130_110744.jpg

    Official Toyota grease for slide pin:
    IMG_20141130_110432.jpg

    Front pads in situ (hard to see a difference):
    IMG_20141130_110515.jpg

    One of the rear pins:
    IMG_20141130_114728.jpg
     
    #1 Former Member 68813, Nov 30, 2014
    Last edited: Nov 30, 2014
  2. bisco

    bisco cookie crumbler

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    thanks! how were the rotors?
     
  3. Former Member 68813

    Former Member 68813 Senior Member

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    Looked smooth with no significant groves. I didn't measure them.
     
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Thanks for that. Did you rotate the rear wheels afterwards, while the back end still up? I'm just curious: with mine there's some drag, even after careful alignment of the back pad pin and the piston cross-pattern. I'm thinking it's the self-adjusting mechanism, always keeps it on the cusp of dragging, but would like to compare.

    (I almost wish the rears were drums, less hassle, more reliable.)
     
  5. Former Member 68813

    Former Member 68813 Senior Member

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    I did rotate them. No drag noticed, but there was some slight noise from pads touching the rotors. That was before brake repressurization. I did touch the wheels after test driving and noticed no abnormal heat.
     
  6. Den49

    Den49 Member

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    Thanks to friendly_jacek. His findings are consistent with others showing that G3 Prius brakes need periodic maintenance. The first brake service should be performed between 24,000 and 30,000 miles or two years and then every 24,000 to 30,000 or two years thereafter if you want the longest possible brake life and best performance. It is a failing of Toyota to include only inspection and not a full preventive brake service in the 2010 Prius maintenance schedule. Grease is cheaper than steel, and brake pads.

    Brake fluid should be flushed at the above intervals if you want to avoid even costlier repairs and maintain the best braking performance.

    I have been and will continue to do the above preventive maintenance. I fully expect I will not have to replace my brake pads, rotors or other more expensive brake system components during the ten years and 150,000 to 200,000 miles I plan to own my 2010 Prius.
     
    #6 Den49, Dec 1, 2014
    Last edited: Dec 1, 2014
  7. Former Member 68813

    Former Member 68813 Senior Member

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    Reflecting on this some more, I'm thinking Toyota dropped the ball on brakes recently.

    I had 2003 corolla made in 2002 that had no brake problems whatsoever till 93,000 miles and 11 years later when it was totaled. It was on a second set of front pads wearing nicely, slowly, and evenly. The rear drums were never even opened or serviced.

    My 2007 Yaris made in 2006 had slightly uneven front pad wear at 70,000 miles, but 50% pad life left and slide pins nicely greased from the factory. Again, the rear drums were never even opened or serviced.

    My 2006 RAV4 had brakes serviced at 50,000 miles due to grinding noises. The front pads had very uneven wear (3/5 mm) and some sliding pins were partially stuck with too little factory grease. The rear disk brakes are fine with even wear of pads (~50%).

    The 2010 Prius referenced here had no audible brake problems at 44,000 miles, but some front pins were stuck due to insufficient grease from the factory, only applied to the pin ends. The rear disk brakes have no obvious problems with slide pins, yet they have uneven and abnormal wear probably from that weird parking brake construction. I use parking brake regularly.

    I'm thinking about writing Toyota to look into it.
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah, I'd be curious how they're turning, after being settled in, driven, parking brake applied a few times. As in: they're completely free-spinning, they're dragging a bit, or they're hard to turn. I'd put mine in the middle category.

    I believe the first few parking brake applications in particular do a tightening up. There's a spring wrapped around a threaded shaft inside the caliper piston. When the parking brake is applied the shaft rotates, screwing itself out and causing the piston to lengthen slightly to take up the parking brake slack. But the spring wrapped around the shaft will not allow the shaft to rotate the other direction, to shorten. In the latter case the spring cinches up on the shaft, locking it and preventing rotation.

    FYI, my rear wheels don't feel particularly warm after a drive, a bit, about same as fronts.
     
  9. Former Member 68813

    Former Member 68813 Senior Member

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    I'll do it for fun this weekend. I don't think there is a problem whatsoever. This AM, I felt very brave and touched the rotors a couple of minutes after some easy driving. Not even warm, all 4 wheels. Trying this on a regular car would result in a burn (I've been there).

    Also, the MPG went back to the normal 46 (this is normal for my wife, BTW, high speed hwy driving) after servicing the brakes. It dipped to 41 couple of weeks before and I thought it was the weather, but probably it was the brakes dragging.

    Edit: I lifted the rear and the wheels spin freely. There is some minimal sound from pads contact with the rotor, but I would not call it dragging.
     
    #9 Former Member 68813, Dec 5, 2014
    Last edited: Dec 7, 2014
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