Tool for installing Xbrace nut inserts

[Bernman]

So I finally got around to installing the Xbrace in my 94 325is. Ron Stygar has already done a wonderful job with <a href="http://www.unofficialbmw.com/~dalus/bmw/e36/suspension/e36_rons_xbrace_install.html">instructions on how to install it</a>, but there seems to be concern among people that installing the inserts in their car that came without them will be difficult. It really isn't hard.

On my car (as on all E36's from what I read) the holes are there, but do not have the insert. Additionally, the holes seem to be slightly small to accept the insert from BMW. You will need to make the hole the right size, and need a tool to "cinch" the nut insert so that it stays in the hole, and doesn't turn. To drill the hole (which is *almost* the right size) you can use either an 11mm drill bit, or a more common size for the US, a 7/16" drill bit. Any hardware store will have this. Buy one with a reduced shank if all you have is a 3/8" chuck on your drill motor. On my car, the four holes for the inserts were already recessed, so I didn't need to countersink them like Ron talks about in his article. You might also be lucky, and find that the holes are already the correct size, but if they aren't, don't worry, they are easy to drill.



To make the tool you will need:

1 M8 x 30 Socket head bolt, or high strength steel (HHS) Hex bolt
2 8mm, or 3/8" *hardened* flat washers
1 M8 Hex nut

You need to use a high strength steel bolt for this since a regular steel bolt will break. The most common one you will find will be a socket head bolt. *Usually* the ones you find at the store are HSS, so you will be ok with that. You also want to get hardened washers, because regular steel will gall under the pressures that they will be subjected to.

To use the tool, apply lubricant to the hex nut threads, and in-between the washers. Use the lube sparingly, and try not to get it on the insert. If you do get any on the insert, just use some brake cleaner to clean them when you are done with all the inserts. I used some teflon spray lube, and it seemed to work fine. Insert the assembled tool into the hole that you prepared, and while holding the bolt still with a long-handled 6mm hex key, tighten the hex nut. If everything is working right, this will cause the insert to compress, filling up the hole. Keep tightening until you feel that it won't compress any more. Back off the nut a little, and then unscrew the bolt. Be careful when you first start tightening the nut. If the insert is turning with the hex nut, instead of staying still, it will back off the bolt instead of compressing. This is another reason why you want to avoid getting lube on the insert threads.

I used each "tool" twice, then changed to new hardware for the last two inserts, since the bolt was starting to look beat up. The hardware was packed with multiples of each, enough to make three tools. The hardware was less than $5 at Orchard Supply Hardware here in California. The 7/16" drill bit was $7.

While us non-M E36'ers don't have it quite as easy as the M3 guys, installing the inserts should not deter you from putting an Xbrace on your BMW.

Good luck, and have fun!
Bernman
94 325is with <a href="http://bimmerforums.com/forum/showthread.php?s=&threadid=3476" target="new">M suspension (almost)</a>, new brakes, and an Xbrace

[pikachu]

hey! thanks for write up and picture! i wish i had an x-brace!

[AceHazardX]

A tool that doesn't cost $48
Thanks for the write up I'm going to get on this right now!

[bimmer95]

I found a trick to keep the nutsert from backing off the allen bolt when you tighten the nut. Put a drop of high-stength Lock-Tite on the bolt before you thread it in to the nutsert. Works great!

[Bernman]

Originally posted by bimmer95
I found a trick to keep the nutsert from backing off the allen bolt when you tighten the nut. Put a drop of high-stength Lock-Tite on the bolt before you thread it in to the nutsert. Works great!

That will do it, though you might want to use the medium strength stuff since all you need it to get it to hold while you start to turn the nut. Once the insert starts to engage with the crossbrace, the insert won't turn any more.

Additionally, you probably won't need to open up the holes. I am pretty sure that they are already the correct size. I think I was fooled by some "goop" in the holes. Clean the crossbrace up real good, and the inserts should slip right in.

Good luck, and have fun!
Bernman

[AceHazardX]

All right I just bought my "tool"
now how do I know how much to torque it for the rivet nut to collapse but not shred?

Also once the rivet nut has collapsed I just take out the tool and put in the m8 that I bought from BMW correct?

In order it would look like this???

M8 - Washer - Xbrace - Rivet and nothing on the other side right? since the rivet collapsed it will hold the other side.

All right well I'm gonna give it a shot tomorrow I tested 2 of the holes and they don't have to be enlarged but I'll see about the other 2 and the "goop" factor.


Fabian

[Hank]

Seems so much simplier and worked perfect for me. I bought a $2 4"x4" "L" bracket has holes (don't need no drilling) ruffed up both the top of the nutsert and where it met the surface of the bracket (on a parking stop smooth piece of cement). Thread the bolt into the nutsert with the bracket in-between, insert the nutsert into the frame while holding the leg of the bracket, tighten to expand the nutsert remove the bolt and bracket, do the same for the next three, then mount the x-brace. In theory its reversing the coefficient of friction of the grease method. Really I can't understand why no one seems to get this?

As they say...works for me!

Hank

P.S. You could probably even return the L-bracket if you're into that sort of thing!

[Bernman]

Originally posted by AceHazardX
All right I just bought my "tool"
now how do I know how much to torque it for the rivet nut to collapse but not shred?

If you use a hex key, and a regular open end wrench on the nut, you shouldn't be able to over torque it.

Also once the rivet nut has collapsed I just take out the tool and put in the m8 that I bought from BMW correct?

In order it would look like this???

M8 - Washer - Xbrace - Rivet and nothing on the other side right? since the rivet collapsed it will hold the other side.

Yes, this is correct.

Hank, your method will usually work just fine, the only problem is there is more of a tendency for the insert to spin when you turn the screw to expand it. The "L" bracket in place of the bottom washer in my tool would completely eliminate any chance of the insert spinning. As with any engineering problem, there are usually plenty of ways to achieve the goal.

[AceHazardX]

ALL RIGHT GUYS
Thanks for the help
tomorrow I should have a new mod on my list!!
I'm gonna try it with the "build your tool" method and collapse the rivets that way.

[cek2]

good technical post. thanks.

[AceHazardX]

After installing those pain in the butt rivet nuts I think I'm gonna get a custom license plate that reads RVTHATR those things took me so long to put in correctly, I tried the lock tite but I used way too much and my bolt was stuck for a good while until I busted that bolt loose.
All in all I think the x-brace was worth it, I feel my front end tighter, but maybe it could be because I just mounted new tires.

Anyway, thanks for the write up!

[Bernman]

Heh, with loctite, "a little dab will do ya". Congrats on getting the brace installed

[KIRASIR]

I installed X-brace 3 days ago using the "tool" above. It was VERY easy.

Thanks for the idea.

SL

[Uber328]

This is an old thread, but one that was very informative and just what I needed!!!

X-brace is going on this weekend!!

[Rahul325]

Be careful when u get the bolt, u need to get grade 8 or higher hardened steel, i got grade 5 and the bolt broke in one of the holes.

[Wayne@PelicanParts]

In working on the new 101 Projects book, I made this useful photo array, which shows how the nutsert is installed with a view of the rear. I thought it might be a useful addition to this thread...

-Wayne

A- Here’s a close-up shot of the nutsert. The outer end of the nutsert contains threads. These threads will be used to install the nutsert, and will also be the mating threads for the mounting hardware for the cross brace. The lip on the other end butts up against the sheet metal in the front axle support bar.

B- Place some red Loctite in two places on the nutsert: on the inside threads (yellow arrow) and also along the bottom lip (green arrow). This will keep the bolt secure in the nutsert, and the Loctite on the lip will help keep the nutsert itself from turning in its hole.

C- With the Loctite still wet, place a nut and two washers onto the hex bolt and then insert the assembly into the nutsert, making sure that at least some of the threads protrude out the end (see Frame E). Lubricate the washers with some WD-40 or other penetrant lubricant prior to installing them on the nutsert. Be sure not to get any oil on the area where you put the Loctite. Let the entire assembly sit for a few minutes as the Loctite hardens.

D- Insert the nutsert into the hole in the front axle support bar. For the purpose of demonstration, I installed this particular nutsert into a spare hole on some shelving in my garage. Use an Allen wrench to keep the bolt from turning, and use a wrench to turn the nut clockwise. I prefer the GearWrench ratcheting wrenches with the reversible switch, because they have a lip that secures the nut while you are tightening it (blue arrow). When you first start turning the wrench, it will require a lot of force as it begins to deform. After a short while though, it will get easier. When you can’t tighten anymore, simply back off the nut, and then unscrew the hex bolt. The nutsert should be installed tight.

E- Here’s a shot of what you can’t normally see when installing the nutsert. The nutsert will deform (red arrow) as you pull the outer threads closer to the lip. This will create a small sandwich of metal material, and the nutsert will eventually be very tightly compressed around the sheet metal hole.

F- Shown here is the backside of the nutsert. You normally cannot see this because it is hidden in the recesses of the front axle support bar. The metal has been deformed so that there is now a lip on both sides, effectively sandwiching the nutsert between the sheet metal.

[318power]

Wayne,
When's the book coming out?
Jason

[bimmer95]

Two things to note Wayne, use anti-seize between the washers and put the Lock-Tite on the outside of the nutsert after the inside Lock-Tite has setup, right before you insert it in to the crossmember. I did this write up a couple years ago, http://www.understeer.com/xbrace.shtml

[Wayne@PelicanParts]

Got it - thanks for the suggestions. Why antiseize? The stuff has never been my favorite material for lubrication, as it's not good for your skin, and it seems to get everwhere. I used WD-40, and it seemed to work pretty well.

As for the book due date, I'm trying to get it printed and published in time for Christmas, but it may miss that by a month or two.

-Wayne

[bimmer95]

Why antiseize?

It does a little better job of allowing the nut to rotate without galling. The washers and nut are under quite a bit of pressure, which is also why I always recommending using a hardened allen bolt and grade 8 hardware. Lower grades tend to strip threads when you're cranking down on them.

[CirrusSR22]

I used bimmer95's instructions and it worked great. No problems at all.

I guess the only hard part is figuring out how much to tighten them.

[Bernman]

Strictly speaking, a nice moly grease should work better to prevent galling than anti-sieze, but really any form of lubrication between the washers should work sufficiently. Since the nuts and bolts are inexpensive, I would recommend using each bolt only twice. I would also *highly* recommend specifying that high strength steel bolts be used. The garden variety fasteners that you will find at the hardware store are usually zinc coated low carbon steel and can fail (twist off the head, break in the middle) under the stress it takes to compress the insert. Fortunately most of the socket head bolts like you show in the picture *are* higher strength and will hold up to a few insert compressions. The parts are so cheap though, using one bolt per insert is not out of the question.

Nice write up Wayne. Thanks as always for the contributions to the community

Bernman

[Wayne@PelicanParts]

Nice write up Wayne. Thanks as always for the contributions to the community

Bernman

Thanks - those are good suggestions, I will add them to the text!

Looks like the book will be coming late 2005 or very early 2006. We'll have to see how quickly the boat from Asia gets here...

-Wayne

[SpeedTheory]

Bump because it's by far the best DIY for the subject, and took me a good while to find.

[taimaishuu916]

My x-brace is sitting in my room for about a month now..im too lazy to drill the holes on my 328i. Plus i dont have the drill bit.