what's wrong with this car
August 27, 2018 8:32 AM   Subscribe

my niece has a car of questionable origin. it lived much of it's life in places with dirt/rutted roads. now it's retired in florida. i noticed something odd and need help identifying the issue.

i'm modestly mechanical and DIYish....

It's a 2006 Chevy HHR. she got a flat and so we plugged it and when we put the tire back on i wanted her to roll forward off the plug so we could double check it with soapy water for a leak, so i happened to be focused exactly on the tire when she put it in gear. when she did, before the car moved, the front left tire...lurched forward. so the car hasn't started rolling yet, foot is on brake. she puts it into gear and front axle seems to quickly roll forward maybe a few inches. i have never seen a car do this before. is this a tie rod end? CV joint? something else? i already crawled down underneath it and tierod boots and CV boot all look ok-ish. i will jack it up when she returns with the keys, but what am i looking for? what kinds of tests can help us identify what this is?
posted by chasles to Travel & Transportation (4 answers total)
You should put the car on jacks to unweight the wheels & fully inspect the suspension. Since its likely high-mileage, look at all the bushings for cracks & play & I'd especially inspect hte control arms.
posted by TDIpod at 8:50 AM on August 27, 2018

If there's no weirdness in the steering (lots of dead-center space when turning the wheel, wheel is cranked over to go straight), it's probably not a tie rod. More likely is the lower control arm.
The lower control arm generally mounts to the frame in two places, and pivots on bolts that run at right angles to one another (fore-aft, up-down; occasionally port-starboard). The pivot points are steel sleeves with rubber bushings. If one of these bushings wears out or tears, the whole arm will pivot about the other mounting point.

The lower control arm mounts to the spindle (brake rotor, wheel bearing, lower mounting point of shock) at a ball joint. Ball joints can be easy, and they can be a motherfucker.

Most lower control arms can be done with jack/jackstands/handtools on the side of the road. Some cannot. If you're asking the question, you probably oughtn't try it.

If you want to confirm the lower control arm, jack the car up, put it on a jack stand, and take the wheel off. Place the jack under the outboard point on the control arm, and lift just an inch or so. You will probably see the arm move (pivot about one mounting point) as the ball joint moves fore-aft.
posted by notsnot at 10:56 AM on August 27, 2018

Yeah, that sounds like a suspension bushing issue to me, if you mean it moved within the heel arch - as in, the wheel went forward but the car didn't. Jacking the car up, putting it on a jack stand (do NOT do this on the jack) and swinging on the wheel in the same direction (back and forth) as the movement you saw should isolate it. If not, lying NEXT (not under) to the car with it on the floor and use a decent flash light and watch various suspension pieces while she replicates the issue should do it. You can use paint pen marks to show relative movement if it is not immediately apparent.

If the wheel rotated but didn't move relative to the wheel arch (ie the centre of the wheel stayed where it is) then it could be a different issue. Clutch, diff, axle or something similar.
posted by Brockles at 5:13 PM on August 27, 2018 [1 favorite]

In itself, this is a 'no big deal' problem, common to high mileage cars. The best way is to jack it up just so the wheel is just off the ground (using a jack stand or something else under the car so there is no possibility of the car falling on anyone). Use a long handled shovel, crowbar or similar, and a block of wood as a fulcrum, and lever the bottom of the tyre so as to put pressure on the suspension bushes. Watch to see which one(s) show movement. They might be rubber bushes enclosed in tubing, or balljoints. If no bushes/balljoints have ever been done, they might ALL need doing, so don't be surprised to see A LOT of movement in there in different places. If I was doing this, if one bushing required replacement, I would do them all, on both sides. If one balljoint failed, I would replace it and the matching one on the other side.

The car is obviously driveable, because it has got you/her this far, so a careful drive to a dealer, workshop, or to your/her home should not be a big problem. This is a DIY job, but on the higher end of the scale of complexity/difficulty. Do some homework before attempting it, including what tools would be required.
posted by GeeEmm at 2:31 AM on August 28, 2018

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