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sefiro
08-14-2015, 06:21 AM
Figured I'd put this in a new thread. Started work on replacing the shifter cables and took some time to look at what other damage might be found from some presumed bottom end wreck.

Found the rear mount for the North/South crossmember had a one partially stripped nut (bolt hole) and one spun nut. It looks like whoever tried the repair must have air hammered the crossmember bolts when reinstalling it.

Any ideas on best repair? The nuts are welded inside a bracket that is welded to the car. I won't be able to use a helicoil on the spun nut. The bracket is thicker sheetmetal but clearly not thick enough to hold a helicoil.

Should I drill the bracket from the side (i.e. remove the exhaust pipe) to get a wrench in there to hold it (or weld a new nut). I'm worried that drilling the bracket might weaken it. I could drill from the interior (I think), That would eliminate the weakened bracket concern.

Anybody have this problem?

METDeath
08-15-2015, 02:01 AM
Rivet nuts are out due to torque being measured in inch pounds. So there went the quick and easy fix idea I had.

Shadowlife25
08-16-2015, 12:45 AM
If you have access to a welder you can have new nuts welded in place. If not, any decent shop with welding capability can do it.

sefiro
08-24-2015, 05:12 AM
Status Update:
I used a 3/8 nutsert on the rear. I am worried about it spinning out - but its holding now. I went with a 3/8 as it was easier to find, and smaller than the 10mm one. Thought is that if it spins out - I'll have to drill it out and the drilling might enlargen the hole thus rendering it useless for 3/8 but usable for 10mm. I'll likely try a 10mm hex nutsert next - as the hex will have better torque holding power. If that doesn't work - then we'll weld one in somehow.

As the nutsert sits proud of the frame body, I drilled out the mounting cushing a little to allow for the nutsert and so the cushiion would press against the frame as designed.

Now (See more below), my big mistake was trying to predrill and tap for a M12 replacement bolt. The drilling popped the weldnut free which led me to the nutsert approach.

I found that the the front mounting bolts were spinning as well. With research, figured out the original owner(s) had bottomed the car and in replacing everything - used some lower grade, too long bolts. One of them had threaded all the way to the solid part of the bolt - where less thread exists and the resulting spin had left a lot of material in the "captured Nut" (vs welded nut). A thread cleanup and a Grade 8/10 bolt of the right length solved this problem.

The other one though was stripped. Not wanting to create the same problem drilling a tapping for M12 - I started looking for a size inbetween. Looking go a \a SAE tpi would match (so there would not be any cross threading) - I found nothing that would work. In the research - I discovered M11 1.5 taps and dies do exist - but no readily available bolts. Wondering why - and with more research - found that Toyota had been using M11x1.5 for head bolts for many years. Unfortunately, the old bolts from 5th gen are M11x1.25 (as tested from my old set after a rebuild). I could have pulled a couple from the junkyard - but bought set from the local supplier. The threads are M11 for about 2 inches - the rest of the bolt has a diameter for M10. I cut the bolt head off to a length needed, and used a M10x1.5 die to the thread the solid bolt section. I could lock a couple of nuts on -- but opted to have a friend weld a nut on the end.

Shadowlife25
08-25-2015, 12:45 AM
That crossmember is basically your "frame". Weld things that are possible to have welded. Nutserts are not rated for that stuff. It may hold for a while, but it is just a stop gap measure, though I am sure you know that. Any bolts that you replace should be rated Grade 8.