Took this off the car today. It's the front brace part of the m7 USS (Under Strut System). I swear this was straight when I installed it... I've scoured the surface of that bent member from corner to corner and I swear there isn't a mark on it. Even stranger, when I first noticed the bend about a year ago it was definitely less bent than when I removed it today.
The cross sectional shape of that bar is not the best for resisting bending. However, I'm guessing it was chosen for clearance issues.
Is that bent up or down? If bent up then I might guess it was hit. If down, then I wonder if the drivetrain torque made the exhaust system bend it. ?? I don't see how so much bend could happen just due to chassis flex. Hmmm?
I saw it as one of the short sided diagonals and based on the recessed mounting bolt hole, I would say "bent up". Steve said there were no scratches..... Hmmmmm
True, plus it's aluminum and though I haven't disassembled it to take a better look I'd say it's not a heavy grade. You guys have commented pretty much every thought I had. For clarity, it's one of the short members (driver side) that connects the sill to the subframe, and the bend is upward. Also, no one else has worked on my car since before the USS, not even for just an oil change. I'm stumped. I've looked at it again and there isn't a dent, scratch, nick or even a smudge in the black anodized finish along that member. There's no sign of anything having pushed up on it much less banged into it. Looks to me the same as it did fresh out of the box other than being less shiny. There are plenty of marks elsewhere but, surprisingly, not on that particular member. Like I said, the real puzzler is I'm certain the bend got worse over time. I'd say the deflection is about double what it was when I found it about a year ago. How could it have been impacted/bent twice in the same place, both times without leaving a trace? Without any evidence of external force being exerted it seems like it might be all down to a bit of chassis flex, maybe under hard cornering? Ignoring discussion of the likely strength of that rectangular aluminum tube, it would take only a very small longitudinal compression along that member (now 425mm) to cause that much lateral deflection (11mm).
Hmmmmm..... I see you live in Maryland.... It snows in Maryland.... Any chance you connected with a chunk of ice that tried to lift the weight of the entire MINI during one of your motoring excursions? That's a possible way it got bent "up" without leaving a mark.....:sosp:
Ice, eh? I suppose that could do it though I would still expect a dent in such soft material. N/A in this case though because I haven't driven it in those conditions. That's what the Honda Element is for...mostly.
Getting older? Speak for yourself... :lol: It's worse, roughly double. First time I saw it wasn't straight I decided the deflection was noticeably less than half the thickness of the member, now it's well past half. Oh well, it's heading for the scrap bin, with something a bit sturdier (hopefully) standing by and about to take its place.
Ok, backing up a bit. I shouldn't have said I hope the replacement brace will be sturdier as in all honesty I don't really know this one was weak. Time to apply a little critical thinking.....I know, to some people "critical thinking" translates directly as "over thinking" but it's what I do. It's obvious I've been implying this thing bent under longitudinal stress because it's not strong enough. There's no way I could possibly know that, I just can't find any physical evidence that something exerted a lateral force to bend it so longitudinal force seems like the logical alternative. As to the increase in bend/lateral displacement over time, I've only gotten under the car to check it twice. I know it bent further between when I first noticed it and when I removed it but I haven't been checking periodically for gradual change over time so I have no evidence it's been bending gradually rather than that it may have simply been bent twice. Also, I imagine it would take far more longitudinal force to bend a tube like this initially than it would to bend further a tube already bent. In other words, it should be less surprising that a tube would bend further once initially deformed than it is that it would bend initially under longitudinal stress alone. So, it could be the only mystery here is that something bent it once without leaving any physical evidence behind. That's much less of a mystery than bending twice, both times by hitting something in exactly the same spot, and both times without leaving a mark. The point is, I only have a couple data points and the rest is supposition. I don't really know how it happened, I just know it bent so I decided to replace it. FWIW, here's the replacement I got from MINI Madness. It looks and feels sturdier and I like where it mounts and what it ties together. It's no cross brace but I think it's worth a try anyway. That pic obviously doesn't say a thousand words and I don't know whether I'll be able to get any good pics of it mounted since my car is only up on jack stands, so here's a link to MM's page with better pics and a video.
I took off the old brace and the car will remain up on the stands and ramps until I finish some other things and install the new brace. I won't have an opportunity to try it without.
I like that it's of a one piece welded construction, eliminating the previous individual sub members that bolted together. You're starting out tighter.... The chrome moly tube will also have a higher resistance to flexing/bending than the old design.