hey guys need some help bought a tranny off of HT and one of the torson bolt holes will not thread. looking all around for a self tapping bolt but no luck, any help would be great. thanks

 

retap it and use the correct bolt
If thats not possible, use a helicoil or timesert

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pdiggitydogg &raquo;</TD></TR><TR><TD CLASS="quote">retap it and use the correct bolt
If thats not possible, use a helicoil or timesert</TD></TR></TABLE>

best advise your going to get!

 

helicoil? timesert? I will do some research thanks for a point in the right direction. I was lost

 

what can you use to retap it besides a tapping bolt? I was using the right bolt

 

Use a 'tap' - a special tool for cutting threads
Find out the thread pitch of the correct bolt and buy a tap that is the same. This will 'chase' the current threads, hopefully making them work.
If you cant do that for whatever reason, you should really just take it to a machine shop and have a helicoil put in.

A helicoil is just threads (wound wire) - you redrill the hole, making it larger, tap it with a supplied tap (special pitch) and then thread the coil into the hole. This coil will match the original thread that was destroyed.
Its not expensive to have a shop do this - less than $20...and you should have someone do this for you, more than likely. Its not hard, but you can screw it up if the hole isnt straight.

Youre sure that the bolt isnt the wrecked piece? Sure would suck to do all that work and then find out the bolt is bad, and not the hole

 

yeah positive. there were 2 hols for the same mount using the same bolt. the top one would thread but the bottom woulnt. end up that the top bolt hole broke in half so I have to use the bottom one. so asking for a self tapping screw is wrong?thanks for the insight

 

You don't want to use a regular tap to rethread the holes.

Normal taps cut material away. If the threads are messed up, as they seem to be, then you'll lose the threads that are messed up, and the threads in the hole will fail.

There's a device called a cleaning tap or a rethreading tap that is designed to re-form the threads without removing any material. They're harder to find (ask a local machine shop where they buy their stuff) but are the only way to re-thread a messed up threaded hole, especially in aluminum.

Guess how I learned the difference.

 

Ive never heard of these special taps...but that doesnt mean anything
Ive always just used the regular ones and have never had any issues

Ive also never seen/heard of a self-tapping bolt either. Screw, yes, but not a bolt. If there was a bolt, youd have to be sure it was the right grade/class and it would probably be fairly expensive.

Just get the hole retapped or helicoiled

 

thanks for all the advice. would you by chance know the size and thread count of the bottom torsen bolt for an ls tranny?

 

Helicoil or Timesert is a better option overall. Cleaning/rethreading taps are hard to find, since thread replacement (the above 2 options) is so incredibly reliable. They're especially hard to find in odd sizes (like the 12x1mm one I need for a crankshaft someone tried to bolt a flywheel to with 12x1.5mm bolts). Check with a local machine shop..they should be able to timesert the hole for $50 or so.