MacPherson strut suspension geometry troubleshooting

[soccerballtux]

My lower control arm ball joint has play in it. Its been replaced and is no better...if you turn the wheel all the way to the side you can rock the wheel and the ball joint will pivot about 15 degrees or so. The car was in a wreck and this is the one thing I haven't been able to troubleshoot or get working again. When I go over bumps I get a popping noise from the ball joint rocking back and forth...the wheel isn't full stable. Most of the time, on the highway etc its fine. But I'd really like to get this sorted if possible.

Can anyone visualize the geometries of this and tell me where I need to install some washers and why?

 

[phucheneh]

Do NOT attempt to modify that for a 'fix.'

Try getting a video of what it's doing. There is no reason a new part should have any play in it or be making a popping noise. And that part does not look new. At all. It looks just as aged as all the parts around it.

If the play is in the spherical joint itself, it is bad and needs to be replaced. If the play is in the stud (you can see the stud and nut moving), the nut is either not tight, or hole is the steering knuckle is wallowed out.

The stud is tapered, as is the hole, and tightening the nut creates a mild interference (press) fit. I highly suspect that the nut is not properly tightened...looks like the boot should appear a bit more compressed.

 

[soccerballtux]

This picture is 2 years after it was installed. The noise was improved but still there. I should have fussed at the place I took it too they said original part was bad. Original was the same this was, just rocking. No play in the joint itself ie in or out just angles.

I'll try tightening it further but I believe that's as far as it will go. The stud and nut rock like your shoulder remains in socket but has range of motion. That's what the joint does.

 

[phucheneh]

If you can lay your hand across the steering knuckle (the big cast part with the eyelet at the bottom) and the stud/nut of the bolt joint coming up through it, and you feel movement between the two, it's not tight. A bad balljoint develops play in the socket, i.e. that part below the boot.

This is not 'bad geometry.'

 

[boomerang]

Evidently there was a picture in this post at some point but if the nut cannot be tightened any further, the knuckle is bad. The accident deformed the tapered hole in the knuckle.

 

[DominionSeraph]

Evidently there was a picture in this post at some point

Internet detective, away! (Google cache shows link to https://www.dropbox.com/s/cyfsi8lp2voufra/1401237384841.jpg)

 

[soccerballtux]

If you can lay your hand across the steering knuckle (the big cast part with the eyelet at the bottom) and the stud/nut of the bolt joint coming up through it, and you feel movement between the two, it's not tight. A bad balljoint develops play in the socket, i.e. that part below the boot.

This is not 'bad geometry.'

No play in the socket.

I jacked the car up and used a 2x4 lever to push the wheel into the well but am unable to elicit the noise I hear or make the joint do anything but ride with the a frame control arm angle changing.

 

[soccerballtux]

Evidently there was a picture in this post at some point but if the nut cannot be tightened any further, the knuckle is bad. The accident deformed the tapered hole in the knuckle.

Its been replaced since the accident and even after replacement made the same noise going over bumps as before just not quite as loud. Nut cannot be tightened any further. The spindle is right up against the flange on the ball joint.

 

[phucheneh]

I still have no idea what the hell you're trying to convey. Sorry.

'...make the joint do anything but ride with the a frame control arm angle changing'?

What?

You're overcomplicating. The joint is bad, or was improperly installed. That's it. Put the protractor away.

 

[boomerang]

If the steering knuckle has been replaced and the ball joint has been replaced, take it somewhere and show them what you're seeing. If as you say in your first post, you can turn the wheel to full lock, rock the tire/wheel assembly by grabbing the tire at the top and bottom and have looseness in the ball joint, you have a bad ball joint or a bad steering knuckle or both. There is nothing else it can be.

BTW, you have contradicted yourself in post 7 from what you said in post 1. In post 1 you say that there is movement in the joint and in post 7 you say there isn't.

 

[soccerballtux]

I still have no idea what the hell you're trying to convey. Sorry.

'...make the joint do anything but ride with the a frame control arm angle changing'?

What?

You're overcomplicating. The joint is bad, or was improperly installed. That's it. Put the protractor away.

The control arm is an a frame shape that pivots up and down with the wheel, attached by the ball joint, depending on the pressure on the shock. As it does this the camber of the wheel changes. Make sense? It takes an understanding of suspensions to follow.

Joint isn't wiggling or anything just swiveling and the spindle is fully backed into the ball joint's flange.

 

[soccerballtux]

If the steering knuckle has been replaced and the ball joint has been replaced, take it somewhere and show them what you're seeing. If as you say in your first post, you can turn the wheel to full lock, rock the tire/wheel assembly by grabbing the tire at the top and bottom and have looseness in the ball joint, you have a bad ball joint or a bad steering knuckle or both. There is nothing else it can be.

BTW, you have contradicted yourself in post 7 from what you said in post 1. In post 1 you say that there is movement in the joint and in post 7 you say there isn't.

The places I take it to point at the aftermarket suspension and say "oh it's because of that". No you idiots, then the passenger wheel would do it too.

For one it can be the strut mount bearing.

 

[phucheneh]

The control arm is an a frame shape that pivots up and down with the wheel, attached by the ball joint, depending on the pressure on the shock. As it does this the camber of the wheel changes. Make sense? It takes an understanding of suspensions to follow.

Go ask your engineering professors about your ball joint problem, we's just dumb greasemonkeys here, hur dur.

Most non-mechanically-inclined females can explain their issue more easily than you. You not only have no idea what your problem is; you seem to be entirely unsure of your own complaint.

But hey, continue to be a condescending jackass.