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Rear Control Arm Bolt - Size and Source?


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This weekend I had a bit of scare, while braking down from highways speed onto a turnoff, my 77 280Z violently lurched to the left and then wandered back and forth while under braking. I pulled over at the next opportunity and after a few minutes of poking around, found the left drop link was only held to the chassis by only 1 of the 2 bolts, with the second bolt partly backed out. Thinking I had located the issue, I limped the car to a friend of a friend's garage in a neaby town, grabbed some replacement 10x1.25 bolts from a local hardware store (though I was bracing to have to drill and tap the chassis to a larger thread as the remaining bolt was completely stripped). Just when I thought I could carry on my coastal cruise, I found the main issue was that the inner front bushing of the right rear control arm was missing, along with the large bolt that retains it. This meant that the front control arm pivot is free to bounce around in it's pocket, allowing the wheel to move back and forth almost an inch. Under normal driving/accel, the wheel would have been pushed forward into toe-in position, but the moment the car begins to deccel/brake, the wheel would instantly pull back and toe out, veering the car to the left.

 

Anyways, I'm now trying to source the missing parts ASAP as I have autocross this coming Saturday. It seems I can probably get a replacement bushing set quickly either through Energy Suspension or a Whiteline kit through Whitehead performance. The bolt however looks harder to find. I measured the thread pitch at 1.5, but I'm not sure on the diameter and lenght, but I'd estimate it at 20mm diameter, 25mm length. Could anyone confirm the bolt size, and can anyone point me towards a source for a replacement, or would anyone have a spare then could send me? I looked on Mcmaster and Carr's website, but it seems all their 20mm diameter bolts are 2.5mm pitch, though M&C doesn't make private sales to Canada anyways. 

 

The offending bolt/bushing is circled in the attached image.

 

Thanks in advance! 

post-1936-0-08818600-1401718871_thumb.jpg

Edited by m1ghtymaxXx
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That would have freaked me out. Glad nothing nasty happened.

 

I have spares of both that old-ball bolt and its lock washer, and the poly bushings (new) too, not exactly close but I can send it Priority post of something quick to get it to you.

 

Check if the gang at WhiteHead have any spares laying around too.

 

Contact me at z240@shaw.ca for logistics

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I managed to gather up all the parts I need in a day despite living on an island with 3-4 other running S30s. For whatever it's worth, that bolt is a m22x1.5, 30mm length, but it doesn't matter as it seems pretty much impossible you'll find one unless it's off another car.  

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Yes M22x1.5 is what I have found is the thread pitch.

 

It is actually a common drain plug thread, granted I don't think any drain plug will be quite long enough. The toyota motors have a banjo fitting with the same thread, doubt that could be used though. They did sell a plug I think 15mm long with the thread pitch at my local parts store from dorman if memory seves. Violates the 1.5 x thread width to length rule, but I imagine might be better then nothing in a pinch.

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Considering all that bolt seems to do is retain the bushing, I don't imagine the thrust load is remotely enough to stress a bolt that size, I would think the 1.5x or even 1x thread rule isn't necessary in this situation. You're drain plug suggestion may have merit.  

 

Anyways I managed to 'borrow' a bolt from a rusty 240Z stored a few blocks away. Big thanks to Whitehead performance for sending me a replacement, and to z240 who offered one up as well. 

Edited by m1ghtymaxXx
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