While installing rigid sub-frame collars, I have encountered a stubborn bolt. This is the left front 19mm bolt.

I did use the impact gun to loosen it and all the other bolts -- this is the only one that is causing me grief. It's taking too much torque to continue loosening it, and probably too much to tighten it all the way back up flush. I'm not sure how to proceed. My assumption is that it IS cross-threaded, so I don't want to make it worse. What should I do?

All these bolts were out/backed off a few years ago when I did the clutch, so I really doubt it is seized in there. Maybe it is, and I just need to keep backing it out slowly (socket wrench, not impact driver).

 

Lower the subframe a tiny bit

blast the exposed bolt with wd-40, where its exposed above the supframe. then tighten back up all the way.

This will get oil into the captive frame nut. A few back and forth and it will come out.

Impact is best, and recommend.

 

Thank you! This did the trick.

Lowered the subframe to expose the top hole really well (stuck bolt still in place obviously) and blasted wd40 up there past the bolt as best as I could. Brown liquid ran out.
Then raise subframe and run bolt up. Then repeat a couple times.

The bolt is fine, no crossed threads . But it was clearly rusted and seized a bit in the centre of the bolt without threads.

I don't totally trust this one now so I'll get a new one. Collars are all in place now, though. So all the hard work is done.

Thanks again. I really appreciate it. I was panicking.

 

Marine white grease will avoid future pobs as is water proof

 

I put a bit of copper anti-seize on the non-threaded section of the bolts. I had it handy since it was what I used on the collars.

I don't get how this bolt got rusty. The car sees so little water. Maybe from washes? Shrug.

 

The threaded part of the two front subframe bolts, above the captive frame nuts, are exposed to the elements, rain, salt.

Coat them completely with a thin layer of grease.

The two middle and the two rear bolts are not exposed to the elements.

 

I followed Billman's advice last year and pre-prepared my subframe bolts for eventual removal. I removed the bolts one at a time, using his method to stop when difficult, lubricate, go back up and then back out. Being a California car, the bolts were pretty clean and did not put up much of a fight. I also used copper anti-seize after cleaning and torqued to spec. I then moved on the next one till I was finished.

 

That's what my stubborn bolt looked like. Probably a bit worse. Rust and even some slightly dinged up threads across that middle section. It's probably not worth trying to clean up.

It's back in now, but I'll order a new one anyway since the car is in the air.

These collars better be awesome!