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Jacking up the rear

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Jonny Zero, Feb 16, 2013.

  1. Jonny Zero

    Jonny Zero Giggidy

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    So I finally decided to throw a set of wheel locks onto my Prius, because I have to park in some not too desirable areas where even stock wheels are known to be stolen. Got them at the dealer (made by McGard), for $41, which is not bad. Online sources want $39 + shipping.

    I decided to take the wheels off to take a look at the brake components while I am at it, and use the scissor jack in the trunk, to familiarize myself with it, in case of a roadside tire swap. I did this in my garage, flat, level concrete floor, and using the designated jack points for the scissor jack, with parking brakes on.

    The front went up and down as expected. The rear started to move to the rear as it went up, twisting the jack some. I lowered it again to check and jacked it up again, same twist. I repeated this on the other side as well.

    I think this might have to do with the torsion beam rear suspension. Since I did this in a controlled environment, this was not too scary. However, in a roadside emergency situation, you don't always have the luxury to park on perfectly flat, level, and hard surface when you jack up the car, and could be dangerous.

    The movement left two indentations on the jack points on the frame, because the rearward movement, it shifted most of the weight to the front part of the jack points.

    LT.jpg RT.jpg

    Have you observed this issue when jacking up the rear of the Prius?

    Should I worry about the dents the the jack left on the jack points?
     
  2. peterjmc

    peterjmc Ping pong in Ding Dang...

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    Dents are not a problem. Its just something that happens with scissor jacks on uneven surfaces. To mitigate it in the future, you should chock the wheels to ensure the wheels don't roll.
     
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  3. DadofHedgehog

    DadofHedgehog Active Member

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    FYI - for shop or garage floor work, the PiP has a jack-up "mushroom" in the center of the car's axis in the rear, by the rear axle. This is great when using a floor hydraulic jack to, for example, install a rear anti-sway bar. Of course, this won't work on the side of the road in an emergency...
     
  4. frodoz737

    frodoz737 Top Wrench

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    Get a small floor jack from Harbor Freight or somewhere else and leave it in the back tray. I jacked mine up once using the factory included because I left mine in the garage after some other work...that was scary...never more. And as mentioned, get some wheel chocks as well.
     
  5. Jonny Zero

    Jonny Zero Giggidy

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    Thanks for all the comments.
    [​IMG]
    Do you agree this has to do with the torsion beam setup on the back, where the the wheel moves to the front some, as it is lowered? I feel that it will drag the car backwards some, until the wheel loses traction, as long as the parking brakes are applied. I feel the best way to mitigate the effect, is to chock the front wheels, and leave the parking brakes off, when jacking up the rear, what do you think?

    I did not chock the wheels when I did this because I was on flat garage floor and did not see this coming. This is the first torsion beam suspension car I have ever owned. I revisited the Toyota manual on jacking up the car with the scissor jack, it calls for the front of the front tire, on the opposite side to be chocked, and parking brakes applied. From what I experienced, the suspension tends to pull the car back when lowered, chocking it per the manual is NOT going to help. Although jacking up a corner with a flat would mean that it breaks traction sooner than a fully inflated tire.

    Still, it is a bit disappointing that using Toyota's jack at its designated spot, following its procedures, left me some dents on the frame, even I have been told that they are not a problem, and not even cosmetic (unless someone is admiring my car with his head under it :) )
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Per Peter up the page: chock the front wheels. There's a pic in the Owners Manual: Prius Wheel Chock.JPG
    That said, I think the rocker panel jacking points are not strong enough, and too much of a knife edge. They should have another layer of heavier gauge plate, locally at the jacking point, with a bent lower edge to give it a bit of width. I'll use safety stands on the rear rocker panel jack points, but not on the front. There I prefer to put my safety stands inboard under the main underbody rail.

    It's worthwhile to pick up a light weight pair of wheel chocks, for tire changes. I've got heavier, solid rubber chocks for use in our garage, but also keep a lightweight pair in the hatch tray. They're under $10 for a pair, pretty light.
     
  7. css28

    css28 Senior Member

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    I changed a right rear flat in my employer's parking lot back in September using the supplied scissors jack.
    I (as usual) had the parking brake applied, and put a crude chock (rock) behind the opposite front wheel.
    I don't recall anything scary or problematic happening.

    P.S. - You do realize that most will be right rear flats (for folks who drive on the right) don't you?
     
  8. Jonny Zero

    Jonny Zero Giggidy

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    I can see chocking the rear of the front tire would mitigate this issue. But the Toyota manual calls for the front to be chocked, which does nothing for the pull back.

    With the lesson learned, I am throwing a pair of wheel chocks in the back. I will be chocking front and back, of the opposite wheel, if I have to do a roadside tire swap.

    SAMSUNG-SGH-I747 ? 2
     
  9. The Critic

    The Critic Resident Critic

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    I don't think that is the correct spot to lift the rear.

    There's a rectangular "box" looking thing that is slightly off to the right. It's mounted to the frame, and is what I have been using to lift up the rear of the car.
     
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    ^ That's for lifting the whole rear, and the only thing I ever use, but for emergency roadside tire change, the jacking points shown in the manual are on the rocker panel. It starts on page 524, goes into detail as to which tire to chock, and so on.

    Another useful addition (that I've never had to use :ROFLMAO: ) is a small piece of plywood, in case the ground happens to be loose gravel or mud, just to give a wider base for the scissor jack.
     
  11. css28

    css28 Senior Member

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    If you're jacking the entire rear with a floor jack, I agree. You'll find that jack point on page 435 of the owner's manual.
    The scissor jack fits over the rocker panel pinch flange, as shown on page 541. I think that's where the OP did it.
     
  12. Jonny Zero

    Jonny Zero Giggidy

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    You are talking about the rear jackpoint for a floor jack to pick up the whole back end. What I used were the spots on the sides between the slots on the pinch, intended for the scissor jack in the trunk. I have a floor jack but I used the scissor jack to familiarize myself with it.:(

    SAMSUNG-SGH-I747 ? 2
     
  13. Jonny Zero

    Jonny Zero Giggidy

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    This is what you are talking about:
    FLOOR.jpg
    This is what I used:
    SCISSOR.jpg
    Lesson learned: I will carry a pair of chocks in the car with my emergency kit.

    To those who had lifted the car with the scissor jack, can you check if you have any dents on the raised bump area on the frame rail shown in the original post?

    Maybe I am just to anal about things being perfectly executed. :confused:
     
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  14. Den49

    Den49 Member

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    The reason your car rolled/pitched to the rear when you jacked up the rear of your car in your garage may be because your garage floor is sloped in that direction. The garage floor is usually sloped towards the exterior garage door so water can flow out of the garage. Whether inside a garage or on the road, when using a scissor jack, it is better that the slope of the floor/ground be away from the wheel being jacked up and a chock be placed like shown in post#6 above. If the slope of the floor/ground is toward the wheel being jacked up, put the chock on the inside (and outside if possible) of the diagonal wheel, but realize you are more at risk of the car slipping off the jack in this situation. Better course is to use the scissor jack only if you cannot use a floor jack and jack stands, ramps or car lift. All of the latter are safer than a scisssor jack.
     
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah, the Toyota illustration I posted looks to have a single chock. Much better to put a chock on both faces of the tire, diagonally across from the corner being raised. Push/kick them in firmly. Do a trial with the car on the ground and parking brake off, to see how effective they are, that they aren't slipping. Though the car is in park the transmission still has a bit of play, enough to test the chocks.
     
  16. Maroon

    Maroon Member

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    As a long time VW owner, you should see the stock jack that comes with my Passat. It's not even a scissor style. It's called "The Widowmaker" for a reason!