I know there are several post on this topic, but none that relate to the issue I've got. I've got the original version the the sway bar. I had the endlinks go bad, so I ordered a new set from bill. They fit in the bar quite nicely, but the end that goes to the control arm is sloppy in the hole. The previous owner must have drilled the holes bigger to use some other end link, but I have no idea what link or what to do at this point. Any help is greatly appreciated.

 

I can't imagine someone would go through the trouble of drilling out the control arm. It already fit's a 3/8" bolt. You could try these http://www.pegasusautoracing.com/productse...sp?Product=3068

Put the tapered end into the control arm, one on each side. That's what I do. I use all 5/16" hardware so it's sloppy in the control arm but fits the sway bar. The sequence for the control arm bolt is as follows: Bolt head, thin regular washer, retaining washer, control arm, retaining washer, retaining washer (for the rod end) rod end, retaining washer, thin regular washer, nylock nut. No problems. If you can't picture it I can mock one up and take a photo of it later today. I have plenty of extra hardware.

 

Well, I happen to have another control arm here and I compared the eyelet to the one on my car. It's definitely been drilled out. I think i'm going to just go to the hardware store and see if I can get a bushing to make up some of the slack.

 

Something like this sounds like it would do the trick: http://www.mcmaster.com/#drill-bushi...liners/=9lo24l.

Having said that, at least on Spec Miatas, lower control arms are considered wear items which deform over time, resulting in a loss of available negative camber. So, you could always replace the lower control arms altogether and justify it to yourself as a performance upgrade.

 

Any decent bolted joint should not rely on the bolt to locate it. Meaning that there's always some clearance between the sides of the bolt and the hole. Whether there's 0.002" clearance or 0.050" clearance, it's the clamp load that prevents the clamped components from moving relative to one another.

Both endlinks on my car have some slop in them, I haven't worried and have seen zero evidence of movement of the swaybar endlink on some very rough surfaces.

However, do check that the 'ball' portion of the endlink doesn't suck into the hole, then there would be reduced travel on the endlink and a spreading load on the hole in the control arm. If that's the case I'd install a thick washer or a rod end spacer (http://www.bsb-mfg.com/jpeg/4020.JPG) if you have it to make sure there's a proper clamp load developed.

 

Wait.... how did you figure this out? what were the symptoms?

 

That's a bit inaccurate. If the bolt is used in a shear application (load perpendicular to the axis of the bolt), then you absolutely want a close fit hole. The conditions when you can get greater hole clearance typically involve tension applications and/or when used with shear and locating pins, like the tranny bell housing bolts.

 

If you need to positively located the parts precisely, then a tight fit on the bolt holes is a good idea. We don't really care about positioning for a front swaybar with adjustable endlinks.

If you needed a tight fit, that would indicate that the endlink could slide relative to the control arm even when clamped up. If that's true the parts will wear quickly from sliding against each other (think about how frequently the load reverses on a sway bar!) and any clamp load will be lost.

Don't get me wrong: if I'm designing something for mass-production I'm going to use a tight fit whenever possible. Especially when it's a single bolt where you don't have to worry about hole spacing tolerances for multiple holes. But it's not the end of the world.

 

Why is a close fit necessary in a shear application? What do you see as the difference between a tension/compression load and a shear load that requires a different clearance?

Assume that the bolt is properly tightened such that the tension on the bolt produces enough friction at the face of the bolt/nut/washer that they do not slide under load.