confuZion3
confuZion3 HalfDork
8/5/08 10:28 a.m.

My Miata has been making a funny knocking sound since I had it at Summit Point a while back. It does it under heavy braking (sometimes), when I turn the wheel (sometimes), and when I straighten the wheel back out (sometimes). The sway bar mounts are not broken.

I got under the car yesterday and investigated the camber and caster bolts after someone here recommended that I look at them. Well, they were loose. Now my camber is definitely out of whack because I moved them while I was trying to tighten the nut.

A couple questions . . . What was the knocking sound coming from - was the bolt likely spinning in place (causing my camber to go nuts)? Or did I just screw that up yesterday when I spun it? How do I fix this? I am going to take the car to a race shop (or someone who can do precision, custom alignments). What should I tell them so that this doesn't happen during the car's first HPDE like it did last time?

Thanks!!

amaff
amaff Reader
8/5/08 10:32 a.m.

1: get a set of these, at a minimum 4 (for the front end), ideally 8: http://www.finishlineperformance.com/store/product.php?productid=16621&cat=328&page=1

2: The knocking was likely due to the control arm having a little play in the subframe from not being tightened down.

confuZion3
confuZion3 HalfDork
8/5/08 11:04 a.m.

You get right to the point! Thank you.

Stargazer
Stargazer HalfDork
8/5/08 11:56 a.m.

Was the noise you heard one loud "crack/clunk" or more of a constant rattling? I wonder if I have the same problem...

Keith
Keith GRM+ Memberand SuperDork
8/5/08 12:43 p.m.

Big clunk is characteristic of a Miata camber bolt torqued down to the factory specifications. The correct specification is Thor tight. And I'm not talking about Per's brother.

You can also get a clunk out of a loose upper ball joint.

amaff
amaff Reader
8/5/08 1:06 p.m.

Yeah, they need to be BT: berkelying tight

I recommend changing all of them because on over half of mine, the "D" hole in the washer side was more "O" than "D". To fix the clunk, all you need is to tighten them. But chances are the alignment's out from having it loose.

John Brown
John Brown GRM+ Memberand SuperDork
8/5/08 1:09 p.m.

The car is totalled, deliver it to Mason Michigan and pick up a Merkur body and a Dodge Shelby TODAY!

DO IT!

Josh
Josh Reader
8/5/08 2:51 p.m.

And for the Grassroots solution: http://partsgroup.com/store.aspx?category=Miata-Suspension&Page=0 Bottom row, second from left.

confuZion3
confuZion3 HalfDork
8/5/08 4:15 p.m.
John Brown wrote: The car is totalled, deliver it to Mason Michigan and pick up a Merkur body and a Dodge Shelby TODAY! DO IT!

AAH!! EVIL MONKEY!! OK OK!! I SUBMIT!

Kendall_Jones
Kendall_Jones New Reader
8/5/08 8:15 p.m.

Early bolts are coarse threaded, later bolts are fine thread. Fine thread is better, get 'em. Torque "the hell" out of them, 'specially if you run track events. I make my engine builder (Mr Torque Wrench) leave the room when I do alignments.

Kendall

wreckerboy
wreckerboy SuperDork
8/6/08 6:56 a.m.

Plus whatever on the torque spec. The later ones are the key (they are the only ones Mazda has sold for years) and the torque spec is officially referred to as "uuuuuGGGHHHHH plus a half turn."

I literally put the car as high in the air as possible on the jackstands, put a jack under the wheel to simulate a load, and use a breaker bar with a jack handle on it to reach spec. I also replaced mine this winter after four seasons of use.

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