Alright, due to the soft aluminum material and the slightly triangular bolt shape, the bottom mount of the rear suspension commonly strips on R56's. Now, I'm about to ship my car cross country and want to toss on the stock suspension rather than leave my extremely lowered airride suspension in the hands of the truck driver. I don't feel comfortable handing that sort of responsibility over to someone I don't know. Anyways, I just have this gut feeling that when I go to swap in the stock suspension, this is gonna be the one time it strips. I've had my suspension in and out multiple times and it always seems like it's pulling out little shreds of aluminum. It would be just my luck that I would strip it right before the big move. Swapping in the stock suspension is easy for me, but I'm just worried about those two bolts. I know you can easily fix it with a helicoil if it does happen, but I'd like to avoid that added stress and work if at all possible. Does anyone have any recommendations or tricks to help avoid stripping that pesky bolt? Is there anything special I should know about loosening and tightening that bolt? I'd really really appreciate any help, MA Thanks
Don't overtorque it? Other than that, I don't know what you can do except maybe use some lubricant on it as you remove it..... Isn't there also room on the back for a nut if you need to? Just drill it thru and buy a longer bolt and nylock nut, maybe? I think I remember reading that those bolts were supposed to be one-use....maybe buy some new ones just in case?
The trailing arm itself is technically designed as a one-use and it's understood that it will strip when removed multiple times. This is due to the triangular shaped bolt that is used to deform the threads and add additional bite. This works great for BMW who doesn't plan to ever remove the bolt, but for those of us who work on our cars it can cause headaches.
Well then, I'd go with the long bolt/nylock nut idea if it will fit, then you can replace it as many times as needed with no problems....and no helicoil to fit.
Yeah, sounds like you need to replace the bolt and use a nylock nut or blue loctite. Just figure out the thread pitch, diameter, length, and head shape and find a bolt in something like a McMaster Carr catalog. Who knows, maybe Home Depot or Napa would have the right bolt so you can buy singles. Or maybe BMW uses a round bolt on the E36 or R53.
Not the R56 trailing arm, but I had a similar issue on a previous car (MINI or Subaru, can't remember), but the fix was to put a not on the far end. The more I think about it, it was the MINI as I had retapped it several times (which was possible with steel inserts).
So that is a possible solution? Buy a longer bolt and just toss a nut on the long end? I wasn't sure if that could stand up to the use. I really just need a temporary fix as a backup plan just in case it does strip. I may get lucky and have no issues threading it, but I've learned that if something can go wrong it probably will go wrong at the worst time.
You could always just drill it and bolt it ahead of time. That's always stronger than a bolt that threads in, too.
the thing that gives tension to the bolt doesn't really matter. the load is in the opposite direction. the main issue is finding a suitable replacement for strength and corrosion resistance. its been awhile so I can visualize what the setup looks like. I think Nathan and I had chatted at length about this when I had issues...let me see if I still have chat logs.
found it. here's the pic we were discussing. you should be able to drill out the arm and put a nut on the end. That's what I ended up doing....the bolt is plenty long enough. either 12x1.5 or 14x1.5, can't remember. my Subaru Legacy GT had a single lower bolt like this on the strut...you had to line up the trailing arm just right and pound the bolt through and put a nut on the other side. The MINI has the same arrangement but the steel trailing arms have a tacked nut on the back side and the R56 is threaded (not sure if there's a nut...)
The R56 arms do not have the nut. When they went to cast arm Aluminium arm they also went with the self tapping bolt. The R53 steel arms could easily have the bolt tacked on for ease of manufacture, the Al ones aren't as easy to tack a bolt too. So while the bolt on the R56 arm costs a little more it actually cost MINI less over time as there is one less part to have to deal with in the manufacturing process.
but, the good news is that you can ream out the arm if it gets cheesed and put a nut on the back side. Wait....that doesn't sound right :lol:
Thanks for the input PGT. Appreciate it Guess I'm just gonna give it a go, hope it doesn't strip, and then use this as the backup plan if it does.
FYI, the bolt is 14x1.5 Did this on a friends r53, and it has worked perfectly since day one. On his, it wasnt 100% needed, but it certainly added a nice bit of piece-o-mind. The threads were just in poor shape in general b/c of all the swapping.
Why don't you convert it to the old R53 suspension with the steel control arms? The only two cars we've seen with these coming loose are lowered to the extreme. And at worse with the steel arms you could cut the threaded part off and weld on a new nut, or just add another nut.
Yah I plan to down the road. I should clarify that I have no issue with it coming loose or stripping. Right now all the parts are still in perfect working order. This thread was simply just me planning for the worst since I've read so many horror stories of them stripping, even on stock cars at the dealer. I just like to be prepared for potential hurdles when I take on projects, you know? I don't have the same issue as the other bagged MINI that you're thinking of because I'm using some different mounting methods to avoid the problem. In the end, I just left it lowered and we loaded it on the car hauler slowly.