stripped subframe bolt

[5spdJunkie]

I did new control arms this weekend and I guess I crossthreaded a subframe bolt during reassembly. I tried to chase it and use a new bolt. no help. now it it just spins in the hole. I'm afraid to drive it anywhere but a shop.

I did searching and everyone says the procedure is to drill it out and retap with a 14mm bolt. not something I really want to do myself. the shop I use says they no longer have the taps needed to do the work. I've called a few other shops and they won't even ballpark it without seeing the car.

how hard is this to do, and could me or a good shop do it without removing the subframe? If I have to DIY where would I even get a suitable bolt?

[mpsmith]

Craftsman makes a great bolt off set it costs about $25, works for round heads and hex. ^ is why I bought it. Drilling out is just stupid

[5spdJunkie]

Craftsman makes a great bolt off set it costs about $25, works for round heads and hex. ^ is why I bought it. Drilling out is just stupid

what does that mean? there's a cap nut inside the frame. it is stripped out, the threads are toast. there's nothing to do but drill it out and retap the cap but.

[evo_ski]

Lol I didn't read thoroughly, sorry.

LOL. That makes twice.

[ADCS]

With a long enough drill bit and tap you theoretically could do it without removing the subframe but it will be very challenging to keep the tap straight. The last thing you want is a broken tap in the partially threaded hole. You will need to completely remove the subframe in order to do it correctly.

Grab new bolts from the dealer. They are torque to yield bolts so they need to be the exact same type and material that was removed. They are also one time use so you should have replaced any of the others that you loosened or removed when you replaced the control arms.

[5spdJunkie]

With a long enough drill bit and tap you theoretically could do it without removing the subframe but it will be very challenging to keep the tap straight. The last thing you want is a broken tap in the partially threaded hole. You will need to completely remove the subframe in order to do it correctly.

Grab new bolts from the dealer. They are torque to yield bolts so they need to be the exact same type and material that was removed. They are also one time use so you should have replaced any of the others that you loosened or removed when you replaced the control arms.

from what I'm reading the New bolt should be 14mm, the dealer will have one of those?

[Willënskraft]

Front or rear? I believe the dimensions for the fronts are different from the rears. I recently ordered the rear subframe bolts as ACDS said it's torque to yield/ one time use. Clicky

P/N: N90981302
Specs: 12X1,5X130X100

[A4SoftWalker]

Apart from giving you props for HE-MAN strength - do you have a picture of the frame and control arm that you "stripped"? I'm guessing lower rear ctrl arm in the front?
If it is the location I think it is...
My guess is the stripped threaded frame nut wont matter much because that bolt has a nut that goes on the end of it. Just use blue loctite on the nut.

Post up a pic so we can see.

[5spdJunkie]

It is not the control arm bolt. That would be easy, just get a new bolt. Its the main bolt that bolts the subframe TO the frame of the car. The nut is stripped and can't be accessed because it's welded inside the frame of the car. A new 12 mm bolt is useless. The nut must be drilled out to a bigger size and retapped.

[Spike00513]

Why did you touch the subframe, to change control arms...

It depends on how easy it is to turn, and whether you ruined the bolt or the car body. The bolts are meant to be weaker than the car body.
The torque spec is something like 86 ft lbs + 1/4 turn. Not something you can easily strip.

[5spdJunkie]

Because you can't remove the bolts holding the lower rear control arms without lowering the subframe. After searching it's clear I'm,not the first to ruin those threads by cross threading that bolt

[walky_talky20]

Yeah. You gotta be careful not to cross thread those kinda things due to the serious amount of work to fix it if you do.

I think you will want to have somebody fix it who has some experience with tapping and such. You don't want to make a bad situation any worse.

As for the one shop bailing because they "don't have the taps", that's kinda silly. You only need one tap for this job and should cost about 30 dollars. Not much compared to the potential labor costs here.

[ADCS]

Because you can't remove the bolts holding the lower rear control arms without lowering the subframe.

Ditto.

[Let it snow]

Because you can't remove the bolts holding the lower rear control arms without lowering the subframe. After searching it's clear I'm,not the first to ruin those threads by cross threading that bolt

There is a way. Back that bolt half way out cut bolt with cutting disk, saw etc. remove remaining bolt. Insert new bolt from opposite side. No messing with subframe. Might save someone a future headache. Sorry for your situation. Good luck.

[Seerlah]

Junk yard subframe. Swap out. Labor intensive, but might be most cost efficient route.

[5spdJunkie]

What would I need with an extra subframe?

[Corrado_Guy]

What would I need with an extra subframe?

I think people are confused because perhaps they have not replaced their own control arms and do not know the procedure. He is talking about the bolts that go vertically through the sub-frame to hold it to the unitized frame of the car. There is no problem with the sub-frame, the problem is in the body of the car where the plate the sub-frame bolt goes into is stripped. Your options are pretty limited here and you are either cutting away the sheet metal above the stripped plate and putting a bolt on top of a longer 12mm bolt which is pretty ghetto or you are drilling and re-tapping.

[ADCS]

Junk yard subframe. Swap out. Labor intensive, but might be most cost efficient route.

junkyard chassis .

I think you need to pull the subframe in order to get a better feel for what you are dealing with. Then you can determine if it can be re-tapped or if something more drastic is required.... like welding a stud to the chassis.

[ADCS]

and I am sure this is a given but obviously don't drive the car around with one of the subframe bolts missing....

[5spdJunkie]

Yeah I won't. The bolt is in there. But it's not very tight. Just spins. I'm pretty much only comfortable driving it it to the shop.

Still not sure what to do. My father in law thinks we can tackle it. Given the seriousness I'd rather have a pro do it. But I can't seem to get a shop to even talk to me on the phone. I want someone that's familiar with the problem and can at least tell me best/worst case before I hand my car to them.

[RichardCVan]

Im actually driving with one of my subframe bolts taken out. I also stripped this when tightening the crossmember after installing my transmission mount. No problems so far. Its been a couple of months now, and I drive on the highway for >60 miles per day for work.

[Seerlah]

Wasn't thinking right when I posted. I have done a fair amount on my car, including dropping the subframe before. Simple goof!

[Spike00513]

[QUOTE=5spdJunkie;10673732]Yeah I won't. The bolt is in there. But it's not very tight. Just spins. I'm pretty much only comfortable driving it it to the shop.

I've heard the solution is Timesert or HeliCoil

[5spdJunkie]

It takes some effort to turn but not much. Its clearly trashed. And its not the rear subframe, its the rear bolt on the front subframe.

[5spdJunkie]

Well Tim's German Auto in Fort Worth finally called me back and gave me a ballpark that doesn't sound too bad. But he said the recommended repair is not to drill it out, but to cut a hole in the frame and weld in a new nut. I can see pros and cons for both methods.

[deyrag]

Well Tim's German Auto in Fort Worth finally called me back and gave me a ballpark that doesn't sound too bad. But he said the recommended repair is not to drill it out, but to cut a hole in the frame and weld in a new nut. I can see pros and cons for both methods.

This is very common with older Saab 9-3's and cut an access hole and weld in a new nut is the general accepted "correct" repair. On the Saab's it is accessible through the floor pan but no idea where to cut on our B6's.

Good luck and post some pics if possible.

[s4silver1]

Lots of bad advice in here. I can't say for sure what size that bolt is on a B6(I have a B5), but all you have to do is get a Timesert kit and rethread that hole. You can do it with the subframe still in there, but it's much easier to remove it. On a B5, the bolt is M12x1.5. Here's a link so you can get an idea what I'm talking about:
http://www.audizine.com/forum/showth...subframe-mount
You can get Timeserts on Amazon and several other places. They were about $100 per kit last I bought one but I bet that's less than a shop will charge to open up the floor and fix that captive nut.

[00passat]

As said above , i would suggest remove or lowering the subframe and installing a timesert.