• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Lowering my amazon (balljoint flip)

Status
Not open for further replies.
Dirty Rick said:
I think any bolt breaking in this situation would be due the the suspension bottoming out.
I think it would be more likely for the bolts to pull through the control arm with the ball joint mounted on top.
I don't see how this is any less safe than using a long shank ball joint.
Look up in your engineering book how strong a 5/16 bolt is and multiply by 4.

I understand the engineering school taught you to avoid this type of fastening, but the sky is not falling.
These models have been around for friggin ever and if this was an issue Ralph Nader (or his Swedish equiv.) would have had a fit.
Click to expand...

That's how this kind of scenario can fool you. The outer two bolts take all the load initially when you put the ball joint on the top side. That is where the risk is multiplied exponentially. There is a reason, plain and simple why it was mounted on the bottom of the control arm. Also, ball joints are designed to minimize stress concentrations. The fasteners that come with those ball joints aren't because they were never intended to carry the load the way mounting the ball joint on the top side requires them to. Fastener design varies based on its intended purpose. That's why moving this ball joint to the top side requires some engineering expertise, not simply moving it and bolting it in place. I won't be driving this car. It just concerns me that people doing this mod may not understand how it changes the stresses on the parts dramatically and could result in a catastrophic failure. I consider a front suspension assembly coming loose so the chassis drops to the ground and there is no steering on one side catastrophic. Dodge Dakotas were doing this due to a ball joint design shortcoming when almost new. Many crashes resulted.
 
OK I'll do it for you

5/16 coarse #8 bolt tensile strength is 7850# x2 is 15,700# not including the other two bolts!

How high are you going to jump this lowered vehicle?

I am not fooled at all, I understand your concern as fastening in this fashion violates engineering PRINCIPALS ON PAPER.

Please don't compare this to somoeones efforts to make a permanently lubricated ball joint with plastic parts.

If you use SAE bolts the tensile strength goes up to a staggering 17,400 for just 2 bolts out of the 4.

I would suggest that at half that amount of load, the wheel would likely no longer be attached to the vehicle (or at least the 4 wheels would no longer be pointing in the same direction) and the bolts would still be holding.
 
On paper it makes a lot of sense. Especially if you spend a couple years studying fracture and fatigue. Even steel has a lifecycle. There is a reason a competent, educated engineer would never make a design like that. You’re looking at that from purely a statics perspective. This is a dynamic situation. Fasteners fail nowhere near their ultimate tensile strength all the time due to fatigue. What do you think happens when you’re driving that car 70 miles an hour and hit even a 1 inch bump in the road? That is the type of thing some FEA computer time would wring out.
 
5/16 UNC minor diameter is .2764 or just over 1/4" with a handy dandy stress riser provided by the threading so I'm calling :bs: on dirty rick's numbers..
 
It gets you off the bump stop in many cases, unless the springs have been cut too much.

I'd guess 1.5" maybe a little less but at least an inch.
 
2manyturbos said:
They are in shear as well as in tension.
Click to expand...

The shear loads don't change.

What changes is the all of the tension loads are placed on the fasteners. This would be a serious situation if it was a solid assembly. But it is not, you have a rubber tire and a spring dampening the load, this reduces the impact load dramatically and this is why (with the bolts properly tightened) the factory mounting doesn't fail.

This is what freaks out engineers, yes it is not a smart practice. It is taught that you should never have bolts holding things up, and there are valid arguments to support that. You should always have bolts holding things together with the actual structure holding things up. But this is violated daily by zillions of cars, every car with leaf springs under the axle has bolts in tension holding the car up!!!

My point is that the load levels needed to cause the bolts to fail are way more than any of the other components will sustain. You will pull the bolts through the control arm before they break.

The loads must not be very high as the designers did not bother to mount the joint in double shear. The control arm is not even boxed, it is not heat treated or even particularly strong material.

To satisfy the engineering books you could bolt a strap across the outer 2 bolts and bend the ends down and weld it to the control arm. This would create a double shear joint. that way you could take out all 4 bolts and the car would not fall. Which would be stronger than the factory mounting (that doesn't fail). Do not test this at home or attempt this without a welding certification and a metallurgical analysis of the strap material!!!! Scratch that idea as the welds would be in tension which is a violation. The ends of the strap would have to be brought around the bottom of the arm and be joined together. You would also have to shim the strap on the front and rear edge of the arm so the strengthening rib would not be deformed by the strap pinching it if the bolts came loose. :-P

The Ironic part of this discussion is that the factory joint mounting will not hold the car up if the bolts are removed!!!! So we do in fact have a Swedish Dodge Dakota! 122's around the world should all be falling to the ground loosing steering and slamming into loaded school buses! Where is Ralph Nader when you need him?
 
Last edited:
Dirty Rick said:
The Ironic part of this discussion is that the factory joint mounting will not hold the car up if the bolts are removed!!!! So we do in fact have a Swedish Dodge Dakota! 122's around the world should all be falling to the ground loosing steering and slamming into loaded school buses! Where is Ralph Nader when you need him?
Click to expand...


When you remove the bolts to change the bottom ball joint you have to lever it out, it does not just drop out on its own
 
mocambique-amazone said:
Yes, in France and in Norway.
No pics

This model is really stupid

Regards, Kay
Click to expand...

How do you know of these failures without pictures.. or proof? Again, without proof, I call alot of these posts just to up your post counter..

I take everyone's posts into consideration, I see the posts have now went off track of my original post.

To anyone wanting to do this modification, just beware the risks, etc.
Make sure there is enforcement, and other safety measures.

I will be doing this, and hey, If it fails, I will be the first person ever to post pics, since no one can show me evidence of failures.
Thanks
 
Tagurit said:
How do you know of these failures without pictures.. or proof? Again, without proof, I call alot of these posts just to up your post counter..
I will be doing this, and hey, If it fails, I will be the first person ever to post pics, since no one can show me evidence of failures.
Thanks
Click to expand...

You are new here. Many of the people posting have decades of experience with racing, fixing, and building Volvo cars, and are known around here for giving sound advice gleaned from experience. A few of them also are on the motherland Volvo forums, where the uber experts are, in sweden and norway. Some are actual practicing engineers. Many of them were lowering these cars before the internet existed. Back then, if your Polaroid wasn't handy, there was no pic. Don`t forget with photofukit pulling there stuff, a huge number of the pictures of things posted in the last 20 years have disappeared.
Do what you have to do, and build your car your way, but calling out the old schoolers on this site is not the way to get helpful advice moving into the future.

This Forum is special in that most of the BS on car forums does not exist here because we dont stand for it.

The fact is, If you are modifying anything from factory, make it stronger and better as a rule. To modify something and have it be the same or weaker is not smart.
Flip your balls, Replace the bolts with stronger and reinforce mount points.
 
Status
Not open for further replies.
Back
Top