E85 Cross Threaded Front Lower Control Arm Frame Holes

[casadefadi]

Hi Everyone and HELP!!!!

I was replacing the oil pan gasket on my 2004 E85 and had to drop the subframe along with the lower control arm.
All was good until I was getting ready to put everything back together when I cross threaded the lower control arm chassis hole.

I have gone to Autozone and gotten the tap clearing kit and it didn't work out. I have also purchased a tap M10X1.5 thinking that I would be able to chase it and it will eventually catch on the correct thread; however, but ended up rethreading a portion of the hole (cringe).

Does anyone have any feedback or have experienced this problem?
I feel like my only option at this point is a Helicoil, but is there even enough material for me to drill out the hole and tap it to take the Helicoil? Also considering this is a suspension member that is also being torqued, is a Helicoil the way to go? Am I writing my death sentence?

thanks for your time,
FG

 

[Z4M-2006]

Hmm,thats a proper mess and a rubbish situation

I dare say a helicoil isnt going to hold in what material you have available.

Could you oversize the tap slightly and get new bolts to secure the mount?


After that your into some major surgery to get a correct fixing,as that is a high stress point mounting.

 

[lucasxdiniz]

Hmm,thats a proper mess and a rubbish situation

I dare say a helicoil isnt going to hold in what material you have available.

Could you oversize the tap slightly and get new bolts to secure the mount?


After that your into some major surgery to get a correct fixing,as that is a high stress point mounting.

TIS suggests helicoil as a solution to this exact problem.

 

[AveZ4coop]

I would recommend a helicoil as long as there is enough metal left after you have enlarged the hole and tapped it to accept the helicoil? Where I work we use helicoils to repair high pressure machinery (2,000 psi) as part of the manufacturers instruction, so they can certainly cope with the torque settings required. You can buy the complete helicoil set from RS components for reasonable money.

 

[Mike6]

What about a nut and bolt provided you can access the other side of that striped thread.

 

[casadefadi]

TIS suggests helicoil as a solution to this exact problem.

what is TIS? Is there a published resource you may know of I can reference?

I would recommend a helicoil as long as there is enough metal left after you have enlarged the hole and tapped it to accept the helicoil? Where I work we use helicoils to repair high pressure machinery (2,000 psi) as part of the manufacturers instruction, so they can certainly cope with the torque settings required. You can buy the complete helicoil set from RS components for reasonable money.

That's actually comforting. Good to know. Thank you!

What about a nut and bolt provided you can access the other side of that striped thread.

Unfortunately, the hole goes into the chassis/frame which seems like a square tube. Trying to put a bolt on the other end means cutting into the square tube and putting a bolt. And then probably rewelding the plate on to prevent any foreign material from getting inside.

 

[Chris_D]

What about a nut and bolt provided you can access the other side of that striped thread.

Not an unreasonable suggestion, but I would suggest that would take you (potentially dangerously) out of the original design spec for the fastening method; different loading forces/patterns etc.

 

[Jakg]

Does anyone have any feedback or have experienced this problem?
I feel like my only option at this point is a Helicoil, but is there even enough material for me to drill out the hole and tap it to take the Helicoil? Also considering this is a suspension member that is also being torqued, is a Helicoil the way to go? Am I writing my death sentence?

Yes I had this problem - helicoiled and been fine since.

I actually helicoiled both upper and lower bolts (got the damaged one mixed up :headbang - been fine ever since, inc a trackday and an autosolo.



More info - https://www.pistonheads.com/gassing/topic.asp?h=0&f=47&t=1755842&i=46

What about a nut and bolt provided you can access the other side of that striped thread.

I don't think you can access it from inside. But you could probably drill it out and replace it with a blind rivnut if you wanted to go down that route, although I don't know if it's up to the task.

I dare say a helicoil isnt going to hold in what material you have available.

TIS suggests helicoil as a solution to this exact problem.

This - https://www.newtis.info/tisv2/a/en/e85-z4-3.0i-roa/repair-manuals/31-front-axle-front-suspension/31-12-wishbones-struts-including-rubber-mounts/GPCo77S

(this link might not work due to the NewTIS situation)

Always a good sign when the instructions talk about how the job could go sideways...

 

[casadefadi]

Yes I had this problem - helicoiled and been fine since.
I actually helicoiled both upper and lower bolts (got the damaged one mixed up ) - been fine ever since, inc a trackday and an autosolo.

Wow, I really thought I was on my own on this one. Beautiful write up on your link!
I just went out to buy a recoil threaded repair kit for the M10X1.5 bolt so I will be trying that in a few hours and report back.
P/N for those who are reading this in the future: 35108

Another question @Jakg, how many helicoils did you use per bolt hole? It sounds reasonable to stack two in there if possible.

 

[Jakg]

Another question @Jakg, how many helicoils did you use per bolt hole? It sounds reasonable to stack two in there if possible.

Just the one.

Bit late but Time-serts are meant to be better than helicoils, but more expensive.
Unfortunately both are very expensive if you need to use just one of them! I was luckily I could borrow one.

I would also suggest checking the threads on the bolt are ok, just in case you end up with another problem...

 

[casadefadi]

What a day!
Thanks to everyone for pitching (pun intended) in to help and provide feedback!

In the end, I used a recoil thread repair kit for M10X1.5 P/N 35108 (see image below).

Using the provided drill within the kit, I drilled out the effed up cross-threaded holes and tapped them with the provided tap (Keep in mind, this kit does not come with a tapping handle). Finally, using the kit, I placed in one of the inserts with the provided tool and then broke off the helicoil extrude that helps torque it in. I did notice that it was really difficult to unscrew the insert back out, so if you're doing this, be extra careful!

I would also suggest checking the threads on the bolt are ok, just in case you end up with another problem...

I actually ended up purchasing new bolts from BMW. My dealership was selling them for $4.50. FCP Euro sells the same bolts for $3.59
https://www.fcpeuro.com/products/bmw-hex-bolt-with-washer-33306760652 "BMW Hex Bolt With Washer - Genuine BMW 33306760652"

cheers,
FG

 

[Z4M-2006]

Lovely job,well done

Happy there was enough metal for for the thread repair kit to get a good hold..

Onward and Upward.

 

[enuff_zed]

Phew, I bet a few beers were consumed after that was sorted.
Well done. What a relief!

 

[rdgreen]

I did notice that it was really difficult to unscrew the insert back out, so if you're doing this, be extra careful!

Well done. If you do manage to stuff up the install of an insert just grab the end of it with a pair of pliers and pull it out (they are designed NOT to be easily removed intact once in). It will unwind and come out easily as a curly bit of wire. Once fixed it's probably stronger than before...and definitely won't strip again.