I was installing my LS1 tubular k-member last night and the last bolt i was torquing (to 130 ft-lbs as per BMR instructions) and the bolt snapped in half.

So, thinking there was just a nut on the other side (inside the frame), I cut out a little window in the frame to see what was going on and how I could fix it.

But, as you can see in the pictures, it is not just a nut I can swap out. What can I possibly do???????

This is the rear-most bolt on the passenger side (all the other bolts were torqued to 130 ft-lbs with no issues). I torqued gradually from side to side. I was also using the factory bolt (as per BMR instructions)

 

Drill out the bolt with a left handed drill bit. You should have done that to begin with instead of cutting up the K-member!

 

Thanks for the input!

I cut into the frame hoping to be able to replace what I thought would be a nut. Don't worry, I would never think of cutting into the new BMR K-member!

After I drill out the bolt, do I then have to tap new threads? Or can I just drill out the middle of the bolt and clean the threads out of what is left? Thanks again

 

there is a nut there in the cage. looks like you can get onto the tapered tip with vice grips now.

 

So what would I do if I can get some vice grips on there? If there is definitely a nut in there, I'm thinking I could cut all of that crap out and put a new nut and now that I have the window, I can use it to keep a wrench on the new nut. What do you guys think?

Would the original threads even be good anymore? Thanks again!

 

There is a couple ways to extract the bolt. If there is much showing or if its flush on the head side you could weld on a nut. sorry just looked closer if you make the opening a little larger you could get vice grips on the bolt tip and maybe start to turn it. Its hard telling if the threads in the cage nut are pulled. or like jim85iroc said put a punch mark on the center of the head and start too drill it out.

 

I'm thinking that drilling it out might not work. It felt like it was almost at 130 ft-lbs when it snapped. I don't think a drill will have enough power to un-torque it. Also, the end of the bolt is not protruding from that sheath looking thing. I think I'll run to the store and get some lefty drill bits and at least try that first. Thanks again guys. This is so disappointing!

 

sorry, I thought the tapered piece in the picture was part of the bolt tip. another choice would be to chisel the spot welds on the cage nut retainer and go back with a washer and lock nut.

 

Fortunately, when youre tightening a bolt down and it snaps, they are much easier to remove than if youre trying to remove it and it snaps.

 

this is very true. I would at least drill it out. you can make your first few attempts with a normal high quality drill bit taking as much time as possible making sure your centered and strait. no need to go all the way through the bolt just past the plate.

Ive often had bolts the refused to come out this way because they were rusted solid . so I kept going up in bit sizes until I was almost to the threaded size. this is when they would come out 99% of the time .
other times I knew the material of the bolt itself was now thin enough I could take a punch and hammed and knock it through.

 

Can you get a pair of needle nose vise grips on the top of the bolt and try and turn it out? The hole you cut may allow you to put them on the top where there are no threads and turn it out. Is it broken off flush on the bottom? If it is once you thread it out some you could use an stud extractor or a tool that is used to remove stripped bolts to get it out.

 

If you do that, it might mar the threads when you do get it released, requiring even more work.

 

What I have done in the past is to heat it up with a torch and let it cool down and then drill with left handed drill bit.

 

Get a small cold chisel and a hammer. Use these to create a slot in the broken end of the bolt, then use a flat screw driver to unscrew the bolt.

 

UPDATE: Ok, yesterday I got the bolt out by drilling a pilot hole and using a bolt extractor. Then I ran a threading tool through ALL the K-member threads and made sure that the bolts went all the way in using just my fingers.

Today, I installed it again. The SAME F******* thing happened!!! I even used grade 8 bolts for the rear 2 K-member bolts (even though BMR says to use the factory ones back here). When I noticed it started doing the same thing I kept backing off the torque until I was all the way down to 75 ft-lbs (hoping to make it at least that tight).

Does this mean there is something wrong with the threads???

Thanks for all the help guys, I am just getting VERY frustrated with all of this. I am doing everything right. I don't know if I have the patience to even attempt this again!

EDIT: here are some pics of what is going on...


above is the gap that shows up after the bolt snaps and comes out. It seems like maybe BMR should have provided spacers for these rear bolts as well. I'm starting to think the bolt is breaking because it is trying to compensate for the gap


above is what the k-member looks like in the car. I wish I could move on from here!!!


Here's the SECOND bolt that broke


above are the two broken bolts

 

What size bolt is that? You need a big bolt for a 150ft/lb torque spec.

 

it's a M12 x 1.75. That is what is used from the factory and what BMR recommends using for the back bolts. I can't upgrade to a bigger bolt because the nut is inside the frame. But this time the bolt broke when trying to torque to only 75 ft-lbs

 

Looks like there is space for a Grade 8 washer in there. My take would be to find something to fill the space, no matter WHAT BMR provided.

 

I'm starting to agree with you. I don't think that would have an effect on anything. I will call BMR tomorrow and see what they think.

My ultimate goal at the time is to just get the wheels on and get the vehicle to a body shop. Do you guys think it would be ok to go ahead and finish putting on the front suspension as it is now (with the gap). The motor is not going in until the car gets back from the body shop.

Thanks again guys for all the help! If it weren't y'all I would have drilled deep into the frame without having tried the bolt extractor (which got the bolt out with ease).

 

Have you considered that maybe your frame isnt straight?

Its possible that the tightening of the bolt is "straightening" the frame, but it cant hold the forces needed to keep the frame straight.

 

If everything looks okay I would just throw some loctite and torque it to 100 ft lbs or something.

Just what I would do. Just depends on whether it felt like it was threading and tightening down. If it "felt" okay as I got it snug, I would just give it a good heave and leave it be.

Although I dont think the frame being "off" would make this happen, I'd think it far more likely that the plate on the k-member you're tightening against isnt perfectly lined up. ie, the jig was off. tolerance stack, etc. So that only one side of the bolt head is seeing any clamping force. But the picture of the k-member around that bolt hole is a bit fuzzy. See if it's really digging hard in one side and not the other.

 

Have you tried another torque wrench? When was the last time the calibration was checked on yours? With higher torque settings, sometimes they can be off a good bit. I was using a cheaper harbor freight 1/2" for a while and it was off by 20 ft-lbs compared to the snap on that I borrowed. Currently shopping for a nicer one of my own before I do my motor assembly.

As long as its threading in clean, and not getting chewed up on the way through, torque down is torque down. I dont think a tweaked chassis is his issue. Unless the hole is so far off, which it doesnt look like it is. I guess the gap could cause some issues, but its not THAT severe. I dont see how that would cause the bolts to snap like that. Lookin at the break, it def looks like its twisted apart vs. pulling or snapping due to stress.

I checked some tables here at work, and for 75% of proof load the torque for an M12 in grade 8.8 is like 65 ft-lbs dry. Assuming you are using a plain medium carbon steel bolt. The k-member doesnt have THAT much going on in the way of forces. Shear shouldnt be an issue because of the locating dowels keeping it from moving much. Tensile...you're really just holding two things together. K-member to the chassis. Yes the motor torques around and bumps on the road can cause a lot of force. But bolts are stronger than most people think, especially in tensile strength and clamp load. That number (130) just seems way high.

Then again Ive never torqued my k-member bolts. Just made them as tight as I could with my air gun, and then gave them a snug with my 1/2" ratchet. Be nice if they, and other suppliers, supplied new bolts. At least then when this happens you could call them and say hey...your bolts, your tq specs...what gives.

 

This is a possibility, but everything seems to be flush when holding the k-member up to the frame before putting the bolts in. But I am doin so using an engine hoist from the front and the k-member has to kind of be swung back because the crane isn't long enough. Next time I go out there, I will have a friend to help me just hold the k-member to the frame to see if everything is truly flush (or maybe come in with the engine hoist from the side). The car has never been in an accident and the engine was never modded so the frame should be pretty solid.

"heaving" is exactly what I did the second time, but I at least wanted to get to a decent torque. The second bolt broke at only 75 ft-lbs.

If the problem is the k-member being a little off, I'm hoping that just sliding a washer in will fix the problem and that it causes no alignment issues or anything.

My 1/2 torque wrench is brand new and matched the 3/8 torque wrench pretty well when I was doing my second stage of torquing. Makibng it "snug" is exactly what I tried to do but my conscience insisted that I at least try to get some kind of actual torque spec on it (again, it broke when using the 1/2 torque wrench set at 75 ft-lbs).

Thanks again for all the help guys. I sent BMR an email last night with a link to this thread. I'll keep y'all updated!

 

Iirc you dont install with the 1/4" washers they sent with it. Iirc they send 4, and you really would need 6 to make it work.

The story;
Same thing happened to me, I have the BMR factory steering, non-coil over. Snapped factory bolts. I went to the Snap-on truck, had my wrench tested, my brand new $100 Craftsman torque was 20% over tourquing. Went to Sears, I was a week out of warranty, they told me to beat feet. Back to the Snap On truck, $700 later, I have a top of the line angle wrench that tested dead on. I then went to Home Depot and got thier $30-$40 deluxe bolt extractor kit and a few bolts that were not automotive grade. Went home and the bolt pulled right out, I literally almost cried out of joy. Went to install Home Depot bolt, it snaps. But I notice that no matter what order I install the bolts, the last one seems to be going in sideways and pulling everthing into alingment. I then try the k-member without the 1/4" washers that BMR sent with it. After all this the thing bolts right into place, no issues. The only thing I could think of was maybe the washers are for the coil-over application?

 

The washers are for when you are not using the bolt in upper coil seat used with factory coils.

 

My story precisely. I was the happiest person ever when the first snapped bolt came out. Only to feel completely broken again after the second bolt snapped.

Yes the washers are for the coilover kit, which I have. What I don't get is how the k-member is supposed to be flush at all 4 bolt points without the washers (for the non coilover application) and STILL supposed to be flush at all 6 points after sandwiching thick washers between just the front 4 bolt points.

I got in touch with BMR and the guy is pretty certain it is not a problem with the k-member.

 

Wait.....flush at 6 points with 4 washers that are added with a coilover kit?

You are starting all the bolts before tightening them?

 

i have the tubular coil-over BMR k member in my '85 LS3 iroc... it uses the 4 supplied spaces in front two positions on each side... the back bolt position will sit flush against the frame

- the bolts are supposed to be torqued to 105 Nm (78 ft-lbs)

- do yourself a favor if you haven't already done so and make sure the corresponding frame nut has good threads by chasing a die through it

- use good automotive grade 10.9 bolts... plated bolts above utility grade 5 are junk and asking for trouble due to the potential for hydrogen introduction, etc, etc... you can get good bolts through your dealer or places like mcmaster-carr

 

I have coil overs. Used the 4 spacers from BMR. Have washers under the other 2 mounts. I think one on one side, and two on the other.

 

not sure if it is flush before bolting it on because I am using an engine hoist to support it before I start the bolts. I need to remove it and have someone help just hold it up against the frame to see if it is flush. And yes, I'm starting the bolts by hand.

Ok, thanks. After this first bolt broke, I chased all the threads and made sure that every bolt screwed all the way in using just my hands. The threads are in perfect condition.

I guess this is what I can expect to have to do.

 

but the coilover application doesn't involve anything between the frame and k-member on the 2 rear bolt locations

 

going by the GM SERVICE MANUAL for the Camaro
The Max TQ for the K Member bolts are 118 ft lbs Max!
thats GM's info. (side note..they have installed a few of them over the years)

clear cut case of wrong torque, AND over torque..


running them down like you would a wheel.

unless you have the $20.000 dollar tool head, that dose all the bolts at the same time..

run them down to 100ft lbs and move on to the nexed step.

 

As alan91z28 mentioned you might want to procure 10.9 grade bolts for all six. I have four different year Helms manuals so I did some quick reading. In my '86 and '87 manuals the torque for the front four bolts is 75 Nm (55 ft-lbs) and the two rear get 102 Nm (75 ft-lbs.) In my '89 and '92 manuals the torque for all six is 160 Nm (118 ft-lbs.) So it seems somewhere between '87 and '89 the recommended torque was changed for some reason. Seeing as the torque requirement for the front four more than doubled it's possible the bolt grade used was also different.

M

 

Great detective work mwfrels that has to be the problem iroc-v is having.

 

Maybe and maybe not. I just used an inspection mirror and a flashlight to see what grade bolts are holding my '86 crossmember in place. Car is currently parked tightly in garage so I could only inspect the back bolts. My '86 has 10.9 grade bolts in the rear positions. Kinda takes the energy out of my previous post. I know all six of 'em are strong. About 15-20 years ago I dropped the crossmember for some other reason I don't remember but I do remember that I tightened all six bolts once the car was back on the ground and level. I did not like what I thought was wimpy torque recommendations so I used a two foot cheater on my eighteen inch breaker and went way beyond the Helms torque. Nothing broke...

M

 

Wonder whats going on?

 

On all my cars those bolts are 10.9, I've had all the bolts on these cars go through my hands multiple times. I replaced the rear ones with 12.9 allen heads on my TA w/ the BMR K member

 

Back in the day, when these cars were current, I remember the mags talking about how the later cars had a bunch of glue (really) because the body dies were wearing out.
This is pure speculation, but MAYBE they upped the torque spec because the cars were working around more, and 70 odd ft lbs was no longer enough to keep things put.

 

Thanks for all the help guys. I did not get a chance to work on the car this weekend. I will unbolt the k-member and hold it up to the frame to see how flush everything is (probably should have done in the first place, but was by myself). Depending on how things look, I may or may not contact BMR again.

I will definitely be upgrading the bolts and using what appears to be the appropriate torque (75-100). Will keep y'all updated. Thanks again guys

 

iroc-v, I just had the same thing happen. Did you get it sorted out, and what did you do? I don't want to have it happen again!

My torque wrench is not the issue, it's a pretty new Snap-On.

 

You're over-torquing them, plain and simple. Heres a chart from a bolt supplier showing max torques per common bolt sizes/grades. Suspension bolts are all grade 10.9 for Fbodys. Fbodys use unplated fasteners so you shoulnt go above 90lb/ft

http://www.imperialsupplies.com/pdf/...rqueCharts.pdf

Do a google search on bolt torque specs and compare if you want to split hairs. Personally, I dont bother torquing common fasteners to a specific rating. Snug it down with the wrench, then a quick yank of the 18" breaker bar is plenty

 

I understand that certain bolts have certain torque specs... however, the problem is that there is still a gap in between the frame and the k-member even before the bolt breaks. the k-member is not perfect (I contacted BMR and they could not care less)

 

RE- the space:Maybe it is the difference between coil overs and factory style springs or maybe it is the variance in our cars down in this area. We both have space between our BMR Ks where they mount. QwkTrip has no gaps.
I just filled the space with washers. Good and solid with about 80 or so ft lbs torque.