M38 Steering Knuckle Flange

RonD2 · Post by **RonD2** » Mon Oct 07, 2019 8:31 pm

Servicing my steering knuckle flanges and on the left side the flange has one of the six 3/8-24NF threaded holes (where the brake backing plate and spindle bolt up) that has questionably light threads --- even after clean-up and chasing them. Five of the bolts are original and their hole threads are good (no helicoils), but this one has a modern grade 8 bolt in it from the previous owner(s). When I took it apart I didn't notice that it was any different than the other five (didn't feel stripped out anyway). They just look light and wore out.

I haven't quite decided whether I want to find out if it won't torque up on assembly --- or just beat it to the punch and put a helicoil in it now. I know this is a critical installation point. Bad things can happen. So I thought I'd ask:

My question: (after searching the forums and threads........) would it be ok to use a helicoil in this instance? I'd rather not buy a new flange if I don't need it.

Thanks!

jnissen · Post by **jnissen** » Mon Oct 07, 2019 10:03 pm

In redoing ours I got over the reluctance to helicoil threaded connections fairly quickly! Not sure if your chasing a trailer queen or a drivers vehicle? If your looking at every bolt or nut as OEM or not then my suggestions likely can be taken with a grain of salt. We reused bolts or nuts rarely. Modern grade 8 stuff is readily available and will easily be a better solution long term. Anytime we ran into a thread that seemed to smear or shear off while getting to final torque values were promptly removed and drilled with s helicolil. On brake backing plates your talking safety critical so I would not hesitate. We did use thread sealer liberally any place threads met coolant or fluid of any type. Looking back I have no regrets. I know it was a solid fix and significantly better than when I took it apart!

RonD2 · Post by **RonD2** » Tue Oct 08, 2019 7:55 am

Thanks on the ok to helicoil the flange! I was pretty sure it's ok, but this is my 1st jeep and I'm still learning. Friendly second opinions and this forum are essential to keeping me straight.

There's no trailer queen in my future. I'm after a safe, reliable driver. I'll re-use hardware when it's serviceable (not pitted, cracked, bent, broken), which isn't very often. I also replace with grade 8 when need be. Plenty of thread sealer or anti-seize as need be. Have had to be patient and hunt for special lengths or unusual heads on occasion. I'm not reluctant to use inserts when need be, just not experienced enough to be confident.

The bank for this project is already way over budget so I try to be practical as much as possible --- without compromising safety or reliability. A helicoil kit and drill bit is about $35 (not cheap), but cheaper than a new flange! All I know for certain is that (1) I can't ignore it, and (2) I'm not going to Bubba it.

jnissen · Post by **jnissen** » Tue Oct 08, 2019 9:41 am

If you have a Tractor Supply nearby... the hardware they have is plated and grade 8. Not all that expensive. My son started buying it in bags by the pound and it was the way to go for us.

RonD2 · Post by **RonD2** » Tue Oct 08, 2019 9:14 pm

10-4. Thanks Jim.