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Fuel consumption increase after service and new brakes.

Discussion in 'Gen 2 Prius Fuel Economy' started by quenching, Nov 2, 2013.

  1. quenching

    quenching New Member

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    So, my 2005 Gen II Prius went for a scheduled service on Wednesday, 70k miles, Toyota main dealer. They called and said it needed new front brake pads and disks, I was surprised but gave the go ahead. There would occasionally have been a mild squealing sound from the brakes at very low speed so I accepted the pads might need replacing, I was surprised the disks needed replacing but it hard to argue about brakes, especially as I only have the car a year (I'm the second owner and it has a full Toyota service history). It had a "major" service, new spark plugs, new front brake pads and disks.

    Since collecting it I've noticed that the engine seems to kick in more often and needs higher revs. The fuel consumption seems higher, normally mid 50's MPG (imperial gallon) now 35MPG. However it hasn't been driven many miles since its been serviced so its a low distance for calculating MPG. I've also noticed that the car seems to slow more quickly without applying the brakes, a regularly driven hill that I coast down at 48kph now only gives 35kph. Also, if I drive on a flat road for a mile or 2 and coast to a stop the front brake disks feel VERY hot, way too hot to touch, drivers side more so that passenger side.

    My suspicion is that the front brakes are rubbing, causing all the above issues.

    The service dept of the Toyota dealer doesn't open weekends so it'll be Monday before I can talk to them. Am I right in my assumption or can anyone offer any advice on something I'm missing?
     
  2. xpcman

    xpcman Senior Member

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    I agree they probably botched the job.
    I suggest you drive the car a few miles and then spray some water on the wheels.. If you get a cloud of steam then you have proof that the pads are dragging.
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Check after an extended drive if the wheels feel warm around the centre, hub area. Also, if you can jack up the back: release the parking brake and see if the wheels turn relatively freely. A slight amount of drag/noise is normal. The rears are drums aren't they? They might have adjusted the parking brake cable.
     
  4. bisco

    bisco cookie crumbler

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    unfortunately, we hear this story way too often. i hope it's just the brakes, many have failed to ever figure it out. sometimes, i think you're better off delaying service until absolutely necessary.
     
  5. fuzzy1

    fuzzy1 Senior Member

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    That is normal for disk brakes, according to the dealership that provided some brake repair on one of my previous cars. The increased drag is also normal, according to the same shop.

    They repeated this mantra several times, until one day the drag was so bad I couldn't maintain highway speed without downshifting, and the heat was so bad the brakes started smoking. If it hadn't been closing time Friday afternoon of a three day holiday weekend, I'd have driven it to the dealership and let it burn in the shop bay entrance.

    Tuesday morning, the repairman's boss admitted to a known problem. Unable to find a trustworthy local shop for that brand, I haven't bought that brand again.
     
  6. quenching

    quenching New Member

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    Thanks folks, I'll spray some water on the front disks after a drive tomorrow and see if I get steam. The fact that the car seems much slower coasting downhill in EV mode really makes me think that the brakes are sticking, could be the parking brake too as I'm fairly sure it's adjustment is a standard service check.

    I checked the 12V battery charge level using the MFD and it's 11.9V at no load, I believe this is lower than it should be but can't see how this would change the MPG from before the service last week. I've read that the battery is disconnected when replacing brakes and can take a while to get back up to full charge, but again why should this effect downhill coasting speed?
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    We had an Accord with dragging brakes. I don't think they would have steamed if I sprayed water on them, but they were uncomfortably hot to the touch. Just saying.

    You might check tire pressures too, if you've been running them higher: dealerships tend to bleed pressures down to what's on the door jamb decal.
     
  8. quenching

    quenching New Member

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    After a drive of about 5 miles this morning with next to no braking I checked the front disks, very hot, sprayed water on them which boiled to steam immediately.

    Also checked the oil level, seems about an inch over the high level mark after letting the car rest for 10 minutes. Invoiced for 5 litres, manual states 3.7l with filter change, I'm not surprised its rounded up to 5l but I'll be fairly cross if they actually put 5l in it.

    We'll see what the Toyota service dept have to say in the morning.
     
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  9. Britprius

    Britprius Senior Member

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    I would be demanding that they put everything right, adding a throttle body clean and a maff clean at no cost. Plus a refund on oil not required. This just as a starting point.
    If the oil is one inch over the dipstick level do not be surprised if you do not make it as far as the dealers, and yes this would be all 5 ltrs.

    John (Britprius)
     
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  10. quenching

    quenching New Member

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    I'll be asking for the problems to be fixed alright, should I ask for new brake disks and pads or should they be OK after only 50miles of driving with them rubbing?
     
  11. bisco

    bisco cookie crumbler

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    better to have them show you the disks and pads compared to new ones compared to them and measured against them.
     
  12. Britprius

    Britprius Senior Member

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    This is a difficult one.
    The pads and disc do require bedding in this will have been accomplished by the fact they are binding. However some abnormal ware will have taken place depending on how tight they are, and how hot they got.
    I think in the distance you have driven this should be minimal. If the ware surface of the discs has turned blue I would say have them replaced (both pads and discs). I would also have the problem logged in case of bearing failure in the near furure (doubtful but possible). If they are just bright steel finish they should be fine.

    John (Britprius)
     
  13. quenching

    quenching New Member

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    A little update, Toyota dealer collected the car yesterday morning leaving a loan car until it was all sorted. Prius returned that evening with brakes repaired, oil level corrected (I haven't checked yet but I'm sure its fine, I will check later though!). Also, throttle body and MAF cleaned, catalytic converter checked, and can of injector cleaner in fuel, plus car cleaned inside and out. A short drive yesterday evening returned 55MPG so seems to be back to normal. The dealers service dept were very apologetic and couldn't have been more helpful, even brought the old brake disks to show me the wear. So, while the problems should never have occurred it was handle well and in a very professional manner.

    Thanks to all here for their advice, very much appreciated.
     
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  14. xliderider

    xliderider Senior Member

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    Glad everything is sorted out. Hopefully your front disks didn't get too hot from the pads dragging on them constantly.

    Watch out for signs that the brake rotors have warped from the heat. If they are warped, you might feel vibration or shimmy in the steering wheel when the friction brakes engage the warped rotors.

    Had this problem on our Nissan Quest van which was notorious for warping the front brake rotors.

    SCH-I535
     
  15. Tony D

    Tony D Active Member

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    Glad to hear that the dealer sorted the issue and did that little bit extra to compound the apology...they are not all robbing bast.... then!
     
  16. salman2k960

    salman2k960 Junior Member

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    What was the problem? rubbing pads or what? and what was the actual solution that ur dealer applied?

    Actually, I think im experiencing a similar problem:
    SYMPTOMS:
    1:MPG drop from 47 to 37
    2:when i put the car in D and release the break,without any throttle, the car would accelerate on its own with speed around 6 km/h. Previuosly, it would move at 10 km/h.
    3:the no. of car leaves in mileage graph has increased. previously, i would hardly get 2-3 leaves in my daily commute to office. but now im getting 8-10! and my battery is green when park my car in office parking.

    what i think is that perhaps there is some brake issue, may be rubbing or something. i have noticed it for a week now. no brake repairs in the recent past which i can attribute as cause of this problem.

    hope to listen from u soon.
    have a nice day.
     
  17. quenching

    quenching New Member

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    I believe my problem was down to rubbing brake pads after the disks and pads being replaced, all seems fine now, MPG is very similar to what I was getting this time last year. If you haven't had any brake work done recently to account of what sounds like rubbing pads then I'd suspect a sticking brake caliper.
     
  18. salman2k960

    salman2k960 Junior Member

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    I carried out that steam test on the discs, and found no steam. the wheels are not too hot. currently, i am keeping my 08Prius under observation. MPGs are fluctuating, but i will observe for a full tank. Perhaps, a detailed car wash has loosen the brakes pads/calipers.
    will update soon.

    SSA
     
  19. uart

    uart Senior Member

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    Hi Salman. Has there been any other work done on the car recently? Tires changed? Anything at all where the 12V battery may have been disconnected?

    Also, could this just be attributed to the colder temperatures and more cabin heat required (which means engine running more frequently).
     
  20. Mendel Leisk

    Mendel Leisk Senior Member

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    Seems to me the "steam test" is way too coarse a measurement. If the wheels are even 10~20 degrees above ambient the brakes are likely dragging.