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Front and Rear Brake Pad and Disk Replacement

Discussion in 'Gen 2 Prius Technical Discussion' started by culp, Apr 20, 2009.

  1. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Front caliper bolts: 81 ft.-lb
    Bolts that screw into slide pins: 25 ft.-lb
    Front axle hub nut: 159 ft.-lb

    Are you replacing a front axle hub as part of the brake job?
     
  2. OldEars

    OldEars Junior Member

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    Thanks. Not planning on replacing axle hub, just brakes and rotors (rotor rusted - not just surface rust but really rusted). The thread above said you had to remove the axle hub nut to change the rotor (maybe I'd better look again - it sounded fishy). At least it's only 159 ft/-lb, unlike the axle nuts on my other car: 339 ft.-lbs!!
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    No, it should not be necessary to remove the axle hub nut to remove the rotor, after you have removed and suspended the caliper above the rotor. There is just one little bolt that holds the rotor in place on the hub, hopefully that will come out without a major fight.

    I strongly suggest that you disconnect the 12V battery negative terminal where the cable connects to the body, before you commence your brake work.
     
  4. excelsior

    excelsior New Member

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    Has anyone else had the problem of all the wear on the front rotors? I've owned my 2006 Prius since new and it's never had the rotors or pads changed. Now the rotors are so worn (19.5 mm) they need to be replaced. The guys at the brake shop will not believe the pads are original as they only look half worn as the cars done 102,000km. The Toyota dealer also tells me they must have been changed to, but they haven't been unless a good fairies done one night unbeknown to anyone. So the dealer doesn't seem at all interested even though I', not interested in making a claim out of anyone since they've given me a good run. Just perplexed. Could the original pads have been too hard and the steel of the rotors too soft? Anyway replaced everything now. Got soft pads so I won't have to fork out $500 for what should have been just $100 to fix the problem. Has anyone else experienced this excessive disc rotor wear?
     
  5. OldEars

    OldEars Junior Member

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    Problem fixed. My son and did both drove the Prius very un-Prius-like for a couple of days, braking VERY HARD (the care has great breaks, if you ever use them which we apparently didn't). Rust is much improved, and no adverse sounds or feeling now that we've scraped off the rotors with the still beefy brake pads. But thanks for your advice (Patrick).
     
  6. Simtronic

    Simtronic Active Member

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    I still have original disks and pads all around at 120,000 miles I have never owned any car so cheap to run, other than tyres and wiper blades I have had to replace a number plate lamp and the 12v battery. Sounds like you have an expensive to know dealer:D
     
  7. Data Daedalus

    Data Daedalus Senior Member

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    I've just had my 2008 Prius Gen II put through its MOT on Saturday. There were no problems - apart from the front Brake Discs and also the pads which were down to less than 2mm or similar.

    The truth is, when braking, I could hear a rather ominous grinding sound coming from the brake discs - especially once my speed dropped below 7mph. Crawling in traffic produced very embarrassing grinding noise too, and a distinct "gronk" whenever I came to a full stop. Despite these unsavoury noises, amplified by the natural silence of the Prius Spaceship in deceleration mode, the brakes were very sharp indeed.

    I was billed £240 for two front brake disc rotors, the front brake pads and the labour. This might sound pricey to some (is it?) and goodness knows I'm not wealthy by any stretch of the imagination, BUT the difference was definitely tangible once I'd got the car back.

    Y'see, I could always hear the faint rubbing sound of front brake disc against pads when setting off in the morning. After braking a few times, the noise would disappear when gliding, but there was the grinding sound as you came to a halt.
    And now?

    Well, it was worth every penny, methinks. All that noise has disappeared! Further more, the car is suddenly much more responsive in natural EV mode! It went up a rather steep incline without the ICE kicking in - I had to press deeper to bring the ICE online. Gliding: The Prius suddenly wants to glide effortlessly for much longer and more freely - it's like it IS more willing!! So, it would appear that tearing down and reassembling the complete front brake components including fitting the new parts and greasing it up in the right places with copper grease has actually made a massive difference.

    I suppose I won't have to worry about the front brakes again during the lifetime of the car.

    Regarding disc deterioration from rust, methinks this comes from the cars spending a lot of time standing outside in damp, damper.....or even close to the seaside locations - or my personal favourite - super foggy zones where mist clings to the ground most of the cold season. As pointed out by all who know, these cars rarely get driven "like we stole it" and having the bonus of regenerative deceleration means those discs and pads rarely get a true workout from most Prii Pilots.

    I'll bear that in mind. My London dealership "Jemca Toyota" were very nice by the way. I was very pleased with the way they exuded good manners, warmth, and transparency while talking to their customers about their cars issues. I waited for my car and had the pleasure of free coffee or tea, used free wifi on my iPad (was on Prius Chat mostly). And my car was cleaned before I got it back. Oh, and they were kind enough not to change my seats settings without my asking! I was impressed. Definitely not a "stealership"!

    And I'll definitely be back :)


    iPad ? HD
     
  8. Simtronic

    Simtronic Active Member

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    It's reassuring to hear there are some good dealerships out there I have heard good things about the one in Guildford too so they handled my steering and HV pump recall very proffessionly giving me the car back cleaned and no bill!
     
  9. Britprius

    Britprius Senior Member

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    [quote="Data Daedalus, post

    I was billed £240 for two front brake disc rotors, the front brake pads and the labour. This might sound pricey to some (is it?) and goodness knows I'm not wealthy by any stretch of the imagination, BUT the difference was definitely tangible once I'd got the car back.

    That's a good price from a dealer. I replaced my own due to rust at around 80,000 miles. Managed to do front and rear discs with front pads included for £70 . Rear pads were refitted after surfacing them as there was about 70% life left in them.

    John (Britprius)
     
  10. baumgrenze

    baumgrenze Junior Member

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    I just reviewed the most recent service document on our '04 Prius. The tech reported 7.5 mm on the front pads and 3.0 mm on the rear drum brake shoes.

    Is this large difference normal?

    thanks,

    baumgrenze
     
  11. OldEars

    OldEars Junior Member

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    Apples to oranges. The fronts are PADS, pressing in on disks between calipers (pinching the disk). The rears are curved shoes, pressing outwards agains the inside of rotating drum. Usually much less material on drum (rear) brake shoes than on disk (front on the Prius) brake pads. I don't know what the limits are, but both of these sound fine to me. Remember, most of the braking occurs from the front of the car--and most of Prius braking doesn't use the brake pads/shoes anyway - just the regenerative braking system (puts power back into the batteries with the generator).
     
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    New front brake pad thickness starts at 11 mm and the minimum is 1 mm.
    New rear brake shoe thickness starts at 4 mm and the minimum is 1 mm.

    I agree that most brake wear will occur on the front wheels since vehicle weight shifts to the front axle under braking.
     
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  13. Andyprius1

    Andyprius1 Senior Member

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    All this brake pad wear in the UK must certainly be weather related. We just don't have anything like that here in California. NOT bragging but simply noting what an influence weather and high humidity can make. Even our severe weather Prii don't seem to have much brake work required. When I sold my 2005 at 105,000 the brakes still looked good, actually like new.
     
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  14. Britprius

    Britprius Senior Member

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    In the UK come winter we have lots of salt and grit spread on the roads. Add to this our somewhat damp summers, accelerating rusting of the discs that the Prius is prone to. Regular forced use of the hydraulic brakes can all but eliminate the problem, but comes with the downside of extra pad ware. The front pads with reasonable use should still last 100,000 miles +, the rears 150,000 to 200,000 miles. The emergency (parking) brake shoes should easily last the life of the car.

    John (Britprius)
     
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  15. Data Daedalus

    Data Daedalus Senior Member

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    I will second what Britprius said by mentioning what the weather outside has been like for the past two days;

    It's been so damp that when I walked out to the car yesterday morning, it was completely soaked in water. There was (and still is today) a very thick "pea-souper" fog in the air. The moisture content in the air is so thick, you'd almost expect those fictitious creatures from the movie "Sharknado" to come swooping by. To make matters worse, even though my iPad insists that the London temperature is just 5c, my Prius MFD accurately displays 2c - and that explains the frost on the roof.

    Today it's just as unbelievably DAMP....!!! Thick fog again and everything from the roads to the vegetation and of course literally every external surface of the car - covered in dripping, dribbling water condensate. In these kind of conditions, it is not surprising that rust gets the better of the Brake Disc Rotors on the Gen II Prius or indeed any other car. On my old Mazda MX-3 "Flying Saucer", I'd come out in the morning and you could see fresh rust on Brake Disc's that were all shiny from the night before!

    Essentially, the UK is the anti-thesis to those places around the world where Prii thrive in super dry climatic conditions. That's why we have premature Brake Disc replacements.


    iPad ? HD
     
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  16. J Conner

    J Conner New Member

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    How do you get 81ft/lb of force on the upper caliper bolt?
    I can only reach it with a short wrench, not a torque wrench.
     
  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Whack the end of the wrench with a hammer, to tighten the bolt? I recognize that you can't measure the torque via that method, but that would be better than nothing.
     
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