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Mustache bar mount bolts not parallel, one quite so


BTF/PTM

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Hi everyone,

I'm in process of doing urethane bushings and coil-overs, and have noticed something fishy. As the title indicates, the mustache bar bolts aren't parallel, and the passenger-side one is kicked forward a solid 15 degrees or so. Both bolts are mounted to the rear of the holes from which they protrude, are straight and are very solidly attached. There are zero signs of frame distress except for immediately at the bolt, it simply looks like the entire bolt was rocked forward. Can these bolts be pulled straight? They disappear into the frame, so I'm leary about trying anything for fear of breaking an internal weld or something equally catastrophic.

As a related question, can this affect wheel alignment? My car has always had a ton of toe at the rear wheels (significantly more at the driver side, for what it's worth), and after reading all of our posts I've figured it's a combination of old metal and old bushings, but could a misaligned diff at the rear pull on the diff front crossmember and thus affect control arm position?

The last two bits of relevant information are that the car has an R200 in it (installed by PO), and sadly it has suffered a passenger-side, rear-end impact that damaged the rear bumper mount and rearmost framework. I have been told by the repair crew that the frame is now straight.

Thanks, everyone.

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This situation requires more investigation. As blue suggests, go ahead and straighten the bolt if you can. Then remove it. It has a 24mm head and its accessible from inside the hatch. Its located between the strut tower and brace that runs from the strut tower down to the floor. Both are under the vinyl trim. Peel it back slowly to release the glue. I've gotten them out with a short 1/2" 24mm socket and a short extension with a long handled L-bar. Its tight. Impact with a u-joint works too.

Since the car was in a passenger side rear impact, this is no doubt what pushed the moustache bar and bent that bolt.

What bothers me is a possible stress fracture of that bolt. Its a hardened bolt and not meant to take a bend of that magnitude. That's why you have to remove it and have it carefully inspected. The act of bending it straight again will make it worse. You can get one from Nissan, if not, I have spares.

I'de want the wheel alignment checked and see reasonable proof of the frame straightening results. The fact that they missed the bent bolt implies they likely didn't take apart or really didn't check things very carefully. Beware.

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The differential is essentially completely independent of the rear suspension and the body. It floats in and on a bunch of rubber. If you crawl under the car and lift on the mustache bar you'll probably find that it's free and not levering anything.

But whatever bent the bolt could have bent something else. Metal can flex quite a ways before yielding, bending other things along the way. The upper half of the control arm mounts are part of the body so if there's a misalignment with the diff mount control arm divots you should be able to see it.

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Hi guys,

We got the bolt out (lots of penetrating oil and a big breaker bar), there is a very, very small warp in it, I will take you up on a spare pair of those bolts if theyre available. That said, we were able to coax the metal back into shape using standard old-school body work techniques (hammers and drifts), as mentioned there was only a small warp right around the pilot nut for that bolt, and now it sits very near vertical (about where the other side sits, close enough that it's not worth fighting for the last tiny bit) and threads in/out far more smoothly.

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