Looking for a bolt or reusing an old one.

[LockDots]

Car: 1997 M3

I'm installing adjustable lower control arms and I'd like to use non-eccentric bolts and nuts. There's no real significant or functional reason for going with this over reusing the old hardware other than that I'd like to go with "standard" hardware because it's no longer adjustable there and the new control arm outer forks may be a little thicker than the OE ones possibly requiring longer bolts.

Digging through realoem.com I see that the eccentric bolt (item #10 pn 33326863853) is an M12 x 1.5 x 82mm.

The inner lower control arm bolt is very similar (item #14 pn 33171090824). It is shorter by 2mm but also has a washer on it, effectively making it just a bit shorter (not sure by how much, which is obviously dependant on the thickness of the washer).





A few questions:

1 - Can I use item #14 safely? In other words, will there still be enough threads for the nut to screw on to?

2 - Should I instead go with item #13 (pn 3332109? It's 6mm longer but has a washer reducing it to being about 4mm longer (just a guess).

3 - Source bolts, nuts, and washers locally from a hardware store like Ace Hardware?

A couple of things to keep in mind:

A - The adjustable control arms going in are SPC brand. I'm not positive at the moment since I'm not home to measure them, but I believe the outer fork that gets screwed to the trailing arm assembly (knuckle?) are probably thicker than stock control arms.

B - The OE bolt and nut combo also use a washer, which may throw off measurement estimations.

I apologize for the size of the pictures and any typos, I'm doing this on my phone, as I don't have access to a computer at the moment.

Thanks in advance!

[jclausen]

Don't by any suspension bolts from ace hard ware just order the factory bolts you are making this way to hard.

[mitch500]

I would go with #13, but then again it's hard to judge without you controls arms in hand. Why not wait till you physically have them then take your measurements and decide. But yea don't use cheap hardware from lowes etc!

I just got all my new genuine BMW bolts and nuts for my rear control arms and such.


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[rajicase]

I did the same when installing my SPC arms. I didn't want to retain the eccentric bolt considering that was no longer the method of adjustment.
I reused the upper inner bolt and replaced the eccentric bolt with one of similar length from Lowes.
Nothing wrong with using hardware store hardware lol; just get similar grade/class bolt as OE and youll be just fine.

[LockDots]

I did the same when installing my SPC arms. I didn't want to retain the eccentric bolt considering that was no longer the method of adjustment.
I reused the upper inner bolt and replaced the eccentric bolt with one of similar length from Lowes.
Nothing wrong with using hardware store hardware lol; just get similar grade/class bolt as OE and youll be just fine.

What I'm leaning towards is getting the upper inner bolt and nut (#13 & #12). My father's got a parts car at his shop I may have to rummage through if the rear end is stable enough (crashed car). Otherwise I'll get equivalent hardware from Ace for the time being in the appropriate grade and then switch it out later on if it becomes a problem.

Related question: Should I use Loctite on the threads of the inner/outer arms bolts and nuts? If so, I'm guessing I should go with Blue?

[ScotcH]

I have never used blue locktite ... we always use red, but I also have big guns

The only place we use locktite is on the rear damper lower bolt. The rest, just torque to spec (81 ft-lbs in this case, I believe).

[LockDots]

Ah, yes you're right. I forgot, these are locking nuts. Red on the shock bolt? I've got an Ingersoll Rand air impact gun for heavy stuff, I think that should do fairly well against red, but does this part really warrant needing red?

[rajicase]

Ive never loctited the rear shock bolt...

[LockDots]

Neither have I, that's why I'm curious to hear about it.

[ScotcH]

Neither have I, that's why I'm curious to hear about it.

I've had it loosen up on track ... maybe it was not torqued to spec, but since then, I just Loctite that one bolt.

[Gordo0208]

Personal recommendation

boltdepot.com

15187 x4
7744 x8
15282 x2


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[pbonsalb]

Scotch is a racer. Track cars expose weaknesses and issues way more than street cars. I have just a street car but in 12 years I have lost a rear lower shock bolt once and found one loose once. But I still don't lock tite since I don't track.

[boarder2k7]

I did the same when installing my SPC arms. I didn't want to retain the eccentric bolt considering that was no longer the method of adjustment.
I reused the upper inner bolt and replaced the eccentric bolt with one of similar length from Lowes.
Nothing wrong with using hardware store hardware lol; just get similar grade/class bolt as OE and youll be just fine.

Agreed, though hardware stores often don't have the graded bolts you're looking for.

I'm fortunate that the storefront for www.nutty.com is a couple miles away. Those guys have EVERYTHING (and good shipping prices if you're not close).

[matthugie]

I'm pretty sure when I did it I reused the eccentric bolt but left off number 11, haven't had any issues.

[LockDots]

Figured I'd update the thread for a little closure for future searches.

I ended up using a Metric grade 10.9 (standard grade 8) M12x1.75x100 bolt and nylon locknut. 100mm is just a bit long as it sticks out past the nut about 10-15mm, but I can always cut it down if it ends up being a problem. That being said theres no reason it should ever become a problem.

[GG Allin]

Why didn't the control arms you're using come with new bolts?

Turner's, which I used did.

[LockDots]

I'm not sure. It wasn't tough to source new ones at least.

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