Take the bolt to HD and fully out its size and thread count. Alternatively, buy a new bolt at the dealer and take it to HD. Then buy a tap to clean up the threads. Also, remove the wheel from the offending side to clean up the threads. Use oil to lube as you're cleaning the threads. Clean the threads and try the bolt.


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Hi Markus,
The bolt looks good; the hole is stripped except for a small 1/8" or so before the bolt emerges from the other end. Trouble is that when the bolt comes out the other side, it runs closely parallel to the hub arm, so putting a nut on that end looks questionable because of lack of room to the side of the bolt.

Murf

 

i'm assuming you're taking about the rear. if i were you, i'd get a new hub. i feel like it would probably be less work than inserting a coil to repair the threads.

if you're talking about the front, people have used the through bolt like in the e90 cars and it works

 

Hi Peyton,
Yes, rear lower shock mount hole in the hub.

Murf

 

That's the trailing arm, I'd try to fix the thread first with helicoil, timesert.

Somebody overtightened that real good. Those threads are strong.

 

Your options are,

Make the hole bigger and retap it, and use a new bolt to fit the new hole.
Replace the hub so you have a new hole that is the right size.

 

Good!

Is retapping/helicoil/timesert a big job, or something my dumb mechanic can do I hope?

"Somebody overtightened that real good. Those threads are strong."
Don't all mechanics use air tools, now (sigh)? :facepalm:

Thanks,
Murf

 

"just replace the hub"

New trailing arm + bushings + wheel bearing = ~ $1000 in parts. + alignment

Why don't you do the helicoil, it's really easy?

Just thought of something else, it would be pretty easy to weld a stud in there too.

 

"just replace the hub"



New trailing arm + bushings + wheel bearing = ~ $1000 in parts. + alignment



Why don't you do the helicoil, it's really easy?



Just thought of something else, it would be pretty easy to weld a stud in there too.

A used trailing arm off a salvage car with usable bushings and a wheel bearing already in place shouldn't be any more than $50. Plus alignment.

I've never personally worked with helicoil or time cert but don't like the idea unless it's a last resort


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^ +1

In my opinion
Time sert is good if your threading the bolt in and out a lot.
Helicoil is very strong and will serve purpose also and is less expensive.

Either way. You could put either in and then thread a stud into either one.

Or.....they make studs with different size ends. Drill and tap....put the large end in the hub and the shock sits on the other end matching correct size.

How easy is this? If you have a drill....then You buy a helicoil that comes with a matching tap. Drill the hole and thread the tapper in there making larger threads for helicoil outside diameter. Then thread helicoil in there...then put in shock. ........look at you tube videos. It's easy. The hardest part is keeping the hole straight for the helicoil. No need to replace hub in this case because it's easy to get a drill in there and it will fix the problem just fine. It's not a rigged fix

Or like he said. Weld a stud on there......I like this idea. Use the original threads to keep the stud straight and weld it in.

Also......I wonder if he can just thread a stud in the original threads with red lock tight and it hold. 40 foot pounds is more than enough for this. The stud stays put and doesn't move. Honestly, I would go this route first because it's not completely stripped. This is what I would do........

 

They work well. I've put timeserts in aluminum blocks

And helicoils..l...even though it sounds backyard. It works well. I like to do quality work and really don't go cheap on anything. I would do any of the above fixes before buying a hub.

I think threading a stud in there would be the best bet. A stud doesn't act like a bolt. Once it's in it never moves and can hold as much as a bolt or more. It wouldn't even have to be in at 75 lbs

 

Thanks Folks!

I like the welded-in stud idea, even better than a through-bolt. I'll run it by my mechanic.

Murf :woot:

 

So the original bolt comes up as: M12 X 1,5 X 60

I think "60" is the length, so putting 10 or 15 whatevers (CM?) to that should give me a long enough stud. Correct?
Any one think Home Depot (cash only pls!) has such?

Murf

 

Re-tapping would the cost effective approach. Sounds like that's all you need. Try that first.

 

Can someone decipher what these numbers mean for this bolt, pls?

M12 X 1,5 X 60

Murf :woot:

 

M12 X 1,5 X 60 means that the diameter of the bolt is 12mm the thread pitch is 1.5mm (i.e. the distance between each thread) and the length is 60mm. Realize also that there are grade/strength standards to worry about as well. Even if Home Depot has the correct size bolt, it may not be as strong as the original. I would assume you would want at least a 10.9 bolt in this location. Others should chime in on this as well though...

Luke

 

Thanks Luke,

Hmmm, HD only has 8.8 bolts only.

Murf

 

Fastenol.....or something similar. They will have what you want.

 

The rear shock mounting bolt has an unthreaded shoulder where it passes through the shock body. Going with a fully threaded stud may introduce binding of the shock when the control arm flexes. As others have said, I'd probably vote for some sort of thread insert. Retapping to a larger size bolt will be problematic for the through hole on the shock body.

-Brent

 

The rear shock mounting bolt has an unthreaded shoulder where it passes through the shock body. Going with a fully threaded stud may introduce binding of the shock when the control arm flexes. As others have said, I'd probably vote for some sort of thread insert. Retapping to a larger size bolt will be problematic for the through hole on the shock body. -Brent

I tell ya, finding the correct stud is harder than I thought. I found a fully threaded one that's 10.9 & long enough, or what is probably the best from "Demon Tweaks" in Britain, at ~ $35.!
Most of the strong studs are too short, being for wheel conversions.

Murf

 

Helicoil, it's super easy and works great.

 

Go with the helicoil if your having problems finding a stud. Or.........make a stud from a long bolt
Helicoil Comes in a kit with the right tap and coil.

If you have a drill bit set. Start with the one that slides easily into the bolt hole. .........As in by putting it in there by hand....
Then put the next size up on a drill and drill it......
Then the next size
And on and on until you have the correct size. It will help keep the hole straight if you build up slowly. The hole will guide the drill bit

If you still want a stud in there.
Find a bolt exactly like the shock bolt but longer.....with a shoulder......grade 8
Cut the bolt head off
Grind it down and place into the hole
Weld it
Use the original threads for the shock nut

Or

Get a bolt longer than the original.......you get a really long one and it will have the smooth shaft (shoulder)
Cut the head off
Using a tap and die set......from lowes or wherever.
Re thread where you cut the head off with whatever you choose and buy a matching nut and lock washer
Thread the original threaded end into the control arm for straightness and accuracy
Weld it in there. Since you can get 40pounds on it. A spot weld will do

 

I had the same problem and came up with a repair that cost me nothing and seems super solid.

My e46 came when I bought it last week with the left rear shock hanging from it's upper mount. I took the bolt off the other side to get the specs on it, M12 60mm 10.9 hardness 1.5 thread pitch, and put it in the side that was without a lower bolt. It threaded in fine, then as I tightened it let go. The threads in the spindle/hub/trailing arm were present but not deep enough to hold the bolt, thus the reason the old one fell out.

Here is what I did, I had a leftover M12 90mm 10.9 1.5 bolt from a rear control arm repair on my e60. The head of the bolt wouldn't settle against the arm as has been stated, there are buttresses that stiffen the support that result in there not being a flat surface for a bolt to cinch down on. I took a stack of copper drain plug washers that I had and put them on the bolt, that spaced it away from the arm, as well they are a bit soft so they settled up very nicely against the arm. The 90mm M12 bolt was a good length, and the threads caught on the arm so there is no play, the nut holds it all in place, and a little loctite gave me a sense of security. It torqued down perfectly. Hooray!