91banditt2

iTrader: (1)

My question is if I welded a grade 10.9 12mm nut to the lower caliper bracket mounting hole for more thread engagement will that interfere with other brake or suspension parts?
When I tapped this hole approximately 1/8" to 1/4" of the threads are not square with the hole. Once I realized what was happening I started over by tapping the hole from the other side so 85 - 75 % of the hole has good threads. Though I'm pretty confident that this wont be an issue with sufficient thread engagement I would be more confident if there were more thread engagement by welding a nut to the spindle.
The hole in question is the lower carrier bracket bolt hole. I am going to be running the LS1 brakes. I have the holes tapped to a 12 mm x 1.75 and to add the nut I would grind the back surface down enough to where a nut would sit flush with the lower spindle bolt hole then running a long 12 mm bolt and snugging it down then snugging a 12 mm nut down onto the 12 mm bolt then do weld the nut in place, a full weld not tasted in place. This way nuts the threads should match up to the threaded hole in the spindle. Every assembly picture I see on here shows the lower caliper carrier bracket bolt either flush with the back of the spindle or just past flush with the spindle. So I was hoping that someone can confirm that this nut welded into place won't interfere with other components.


Any insight would be welcome.

novaderrik

i'd just run it as is, but you could also get a helicoil kit and redo the hole with good threads the whole way thru.

or drill it out for the next bigger size bolt.

91banditt2

iTrader: (1)

I've thought about using a heli coil and I just checked with our machinist and we do have some 12 mm x 1.75 heli coils here at our shop but I just don't know if I trust them in a high stress area like the brakes. I'll have to research it.

turd_gen

If I were you I'd drill them out and tap for M14 x 2.0 just to be safe. The extra work is definitely worth the piece of mind, especially for something critical like brakes.

scooter

iTrader: (11)

at 14mm, there probably won't be enough meat around the hole that is flat, there is hardly any plateau around the boss as it is on the front side

BBU.COM

I concur, I have installed another vendors C6 bracket to a 3rd gen spindle that uses a 14x2.0 fastener and if its not the right spindle... that size hole leaves zero surface area for the bracket to sit flat.

91banditt2

iTrader: (1)

That was my thinking about going to a larger size bolt.

I'm confident there is enough good threads but unless someone tells me I can't I'm just going to weld a nut on for adictional confidence.

sofakingdom

iTrader: (1)

I've never done that to that specific thing; but I can't see where it would be a problem, if properly done. I.e. in such a way that it didn't weaken the metal around the nut. Not sure what heat-treatment those got during mfr and whether that would be affected.

I'd also have no problem w a Heli-Coil, as long as drilling out for it doesn't make the metal around it too thin. They're MUCH stronger than most bulk metal.

You could also always just grind the back side down flat, use a longer bolt that sticks well through, and just run a nut up onto it. (as long as it doesn't hit anything back there which I don't think it would)