Just for those who are wondering what the hell the rest of us are talking about...here is a picture showing the sway bar end (at the bottom) set on the stiffest setting...the soft setting would be at the end of the bar. The green looking thing is the uplink arm (metal in my car - 97 2.8QM), but apparently now plastic (and larger) in the 98 and 98.5 cars. The other thing in the picture is the half shaft (axle) that goes from the differential to the wheel...as you can see it is quite far away from my uplink arm. This is one reason why I do not have any damage. Again, some aftermarket sway bar owners are finding that the uplink arm has been damaged by rubbing against the half shaft/axle...and in one case it actually broke on one car. The other part of the damage is seen as stress cracks in the subframe itself. Jim Simone is unfortunately the one with the most damage that I have seen in this subframe area.<p>So, in conclusion, people with aftermarket sway bars should look to see if they have any damage in either the uplink arms or the subframe where the sway bar bushings attach to the subframe. Hopefully, you will be like me...no apparent damage.<p>Steve S.<br>97 2.8QM
10-12-1998, 03:54 AM
10-12-1998, 09:26 AM
Steve,<p>I have the plastic link, so the picture is really instructive. First, that whole assembly travels upward in compression. It does seem like the link or the end of the bar could easily hit the halfshaft in full bump.<p>The variable here might be using this bar on a stock or soft spring!!!!! If the bar transfers with soft springs it could move enough to hit. If you have stiff spings, the assembly really doesn't move much.
10-12-1998, 10:06 AM
10-12-1998, 04:33 PM
and sustained major damage to both my plastic uplinks and my subframe.<p>In my case, it seems like the stiffer suspension made it worse. We'll see what Neuspeed has to say after they receive my broken subframe for analysis later this week.<p>Jim<p>PS: I'll be developing my pictures in the next day or so and will post a couple after scanning them.
10-13-1998, 06:46 AM
Jim,<p>I look forward to seeing the pics. Do you have the HD or the sport Bilsteins? Can you look at your bump stops and see if they are cracked or show signs of compression? Did your halfshaft get the paint scratched?<p>The action of the bar is to transfer weight to the other side's spring. If the compressing spring is stiff, then the bar can only move slightly, regardless of the link and mount. Since both springs are stiff, the compressing side only moves a little, and the other side will only have a small movement.<p>Under a really hard bump/hole on one side then a large twisting force is put on the whole assembly, which can tear out the mounts. This is different from cornering because the transfer is very abrupt (fast). If both sides hit a bump, the bar just rotates and has no force on the links, UNLESS the center bar mounts are sticking/not rotating (then there is an abrupt transfer again).
10-13-1998, 06:59 AM
I saw Jim's car on the rack at Carlsen...the half shafts hat been hitting the plastic uplink arms and the plastic arms were definitely worn down by hitting the half shafts. I can't believe his commute did this....he does live in the Mountains near Santa Cruz, but the damage done looks beyond just regular driving stresses and strains. He didn't even go in any autox or driving school events yet.<p>Steve S.<br>97 2.8QM<br>
10-13-1998, 07:21 AM
It looks like it could be a very light scratch from the uplinks. But then again it looks like dirt also. Any ideas? Also I have a early 98 (April production if I recall) and I have metal uplinks. It doesn't appear that all 98 and 98.5 have plastic uplinks.<p>Drew<br>
10-13-1998, 09:05 AM
10-14-1998, 10:01 AM
Sorry that I haven't gotten to those pics yet. I still have 10 pictures left on the roll and wanted to take some "after" shots as well. Unfortunately, they haven't finished up with my car at Carlsen yet but should be done today. I'll try to get them up by the end of the week.<p>I do have the HD Bilsteins on the front (#B36-2079) and Sports (#BE3-2669) on the rear. We didn't notice that the bump stops were showing any signs of compression although we did try to measure the clearance between the half-shaft and the uplink with my standing in the trunk. Steve estimated that there was only a 2-3 mm space and attributed it to the lowering of the rear suspension. Both links were gouged out about 5-6 mm but it's hard to determine how much of the damage occurred before the mounts cracked.<p>Contrary to what Steve Sherwood speculates, I think that the roadways I drive on my daily commute play a significant roll in the damage to the subframe. I checked the movement of the bar before I removed it and found that it rotated freely with the endlinks unbolted. I think your suggestion that a large bump on one side could put sufficient twisting force on the mounts to crack them is well-founded. I encounter quite a few of those negotiating my way up Page Mill Rd. to Skyline Blvd. I just never thought that it could be that damaging to the car.<p>It's also interesting to note that some of the folks with just the Neuspeed bars on a stock or sport suspension have experienced broken uplinks. It's still not clear whether the "stiffer" setting of the bar also plays a significant role, although I'm guessing that it does since there was no obvious damage to the mounts in my car until I re-adjusted it.<p>The subframe should be to APS/Neuspeed by the end of the week. So, we'll hopefully hear what their analysis is soon thereafter.<p>Jim
10-14-1998, 01:29 PM
Jim,<p>That was some great information! As beat as the subframe damage is, I think it was better than having the halfshafts bouncing around, IMHO. <p>My guess is that Audi will have to cover the breakage because they changed the link spec to plastic. But the halfshaft damage is strictly Neuspeed for making the arms too long for the lowered suspension.<p>I suspected bushing binding, but your testing disproves that. I really don't think that the increased bar thickness makes a difference. The mount is too weak. <p>So, if you cut the end of the bar off (at the stiffer hole), and switch to the plastic links you should be fine.<p>Actually, I am really suprised about the link issue. If you have the Bil. sports and stiffer springs the bar should not really come into play except on a severe single-side bump. On my SCCA AWD car I had to take off the rear bar when I went to stiffer struts and spring because I got snap oversteer on rough roads. The bar really just helps in transitions.
10-14-1998, 11:33 PM
Well, I now have my car back (Thanks, Steve Shupe.) with both a new rear subframe and new connecting links (plastic).<p>I drove my usual route home and found that the factory sport stabilizer bars did pretty well with the stiffer suspension. So, until they re-pave the roads, I'll not be re-installing the Neuspeed bars. Plus, until they come up with a support bracket, I'll be feeling a little uneasy about using that larger rear bar again.<p>Fortunately, there was no apparent damage to the half-shafts, but Audi didn't volunteer to pay for anything since they attribute all the problems to the Neuspeed equipment.<p>Bushing binding could have explained it but since it rotated freely, I'm still leaning towards the thicker (read: stiffer)bar. Unless the bushing is not designed properly, it's hard to imagine that all three of us (Steve, Sharon and I) could have somehow overtightened the brackets.<p>"So, if you cut the end of the bar off (at the stiffer hole), and switch to the plastic links you should be fine." I assume you mean "...switch to the *metal* links." But, both Steve and Sharon _have_ the metal links, so that's not the only factor here.<p>Thanks for all the input,<br>Jim<p>
10-15-1998, 07:45 AM
Jim,<p>I remember now that you had the plastic uplinks. I actually would NOT reccomend the metal ones because they work so much better. How was your link damaged, was it twisted along the long axis?<p>I think that the difference in stiffness on the short arm of the bar between the factory and the Nuespeed bar is irrelevant. Why? Because the FACTORY short arm section is essentially unbendable. The sway bar works by torsional stiffness on the center of the long portion of the bar.<p>If the subframe mounts are really weak, then they will twist diagonally with a stiff bar.<p>So if the bar was too stiff (which I don't think it is), and the mounts worked properly (which I think they did), then the force would be concentrated on the opposite link. <p>If the bar was designed properly (to rotate evenly with the movement of the lower control arm) and the links had full rotation then the force is concentrated on the single shear attachment of the link. This would impart a twist on the link end, probably cracking or at least discoloring the END of the link. This would be most obvious on side of the car that hit the bump/hole.<p>If the bar had not been well designed then the whole link would twist, damaging the CENTER of the plastic link, on side of the car that hit the bump/hole.<p>These are the remaining failure modes. With a metal link the force would be moved to the mount, because the link couldn't absorb any force (confusing the entire issue).
10-15-1998, 12:05 PM
In truth, the only obvious damage to the plastic connecting links are the grooves that resulted from rubbing against the half-shafts. I had them replaced to avoid any future problems.<p>You're right in saying that the stiffness of the short arm of the stabilizer bar is probably irrelevant; I was thinking that it might factor into clearance issue with the half-shafts, i.e., referring to its length not its stiffness.<p>I follow your reasoning regarding the forces on the bar, but isn't there still some downward force imparted to the subframe mounts even when it is working properly (no binding within the bushings)? What if the half-shafts were preventing the connecting links from their full range of motion?<p>I guess that it's going to take an extensive engineering analysis of the suspension mechanics to figure this one out!<p>Thanks again for your ideas. We'll figure this out yet!<p>Jim