Knuckle stud torque

[SteelHunterFJ80]

Hello all,
I'm about to dig into the classic knuckle job and got all new fasteners and wheel studs. Going to do a full refresh with part time kit, abs relocation kit, rotors, pads and eventually new calipers.

Moreover, I've searched high and low on the forum and YouTube but can't seem to find consensus on the torque required on the front knuckle studs. Reliable sources put it at 37 ft lbs and 45 ft lbs.

Any updated guidance on this?

 

[smorkington]

1/4 turn before it breaks

 

[LXDOC]

Stud snug in knuckle (max 20 ft/lb).
Nut torque 71-79 ft/lb.

 

[SteelHunterFJ80]

I thought someone quoted @OGBeno at 37 ft lbs in another thread...20 seems way too little

 

[NeverFinis]

IMHO, because the are studs, tighten until snug. The torque specification comes into play when you tighten the nuts onto those studs.

 

[LXDOC]

Yep

 

[Kernal]

IME one method is to first super clean/degrease the knuckle stud holes (threads) and the stud threads themselves, put a drop of blue loctite on the threads in the hole and another on the stud threads. I may use a bore brush repeatedly or a thread cleaning tap (not cutting) with carb cleaner/acetone ie: scrub, spray, scrub, spray to clean the threaded holes.

Once the threads are squeaky clean and after a couple drops of blue loctite then install the studs and tighten all the way down to the unthreaded segment and keep going slowly until you feel a wall (stop). Many people feel more comfortable with a specific torque setting but IME if using a smaller wrench and closely watching/feeling what you're doing it's safe. Haven't had any studs or nuts come loose following that procedure.

If you want to go a bit further, once the studs are installed, then switch to working inside the (cleaned) knuckle, you can first use a Q tip to soak up any loctite that was pushed up in the threaded holes (which open into the knuckle cavity) as it won't harden in air. Then put a dab of sealant/FIPG into the open stud holes to seal them off ie: so oil in the knuckle (bleading from grease or leaking past the axle seal) won't work it's way down past the stud threads. The loctite used on the studs when installing them should prevent that so this is just extra insurance IMHO.

All the above may seem to be a bit OCD but IME/IMHO it helps prevent studs from coming loose and oil from working it's way past the threads.

Edited for clarity here's the method in short form:

80-Series Knuckle Stud Installation (one method that works IME)

1. Chase/wire-brush the threaded holes in the knuckle – clean/degrease completely
2. Blue Loctite 243 (or 242/1364E) on the short threaded section that goes into the knuckle (another drop in the hole if you want)
3. Thread stud in until the unthreaded shoulder contacts the knuckle face
4. Using an E12 Torx (if using star type studs) snug firmly until shoulder is fully seated ( ie: it stops positively)
→ Stop turning once the shoulder bottoms snugly
5. Wipe excess Loctite
6. Install steering arm with new cone washers
7. Torque the four nuts cross-pattern to 97 N·m (71 ft-lb)
8. Optional: seal the threaded holes from the inside of the knuckle cavity


Check RM315E (General Repair Instructions) IIRC discusses tightening of threaded studs. Lots of discussion in the past about how much torque to apply to the knuckle studs, not enough and the studs may loosen up even with the nuts torqued correctly, too much torque and you could deform the threads of the knuckle. The method above results in maybe 1/8 -1/4 turn after the unthreaded shank contacts the upper edge/lip of the threaded hole.

 

[Malleus]

For all unspecified torque values, use this chart and table (from the service manual):

Once you've identified the appropriate fastener from the chart on the left, you need to find the correct torque value for that size from the table on the right.

I use this so often, it's posted on the wall in my garage.

 

[SteelHunterFJ80]

For all unspecified torque values, use this chart and table (from the service manual):
View attachment 4034082

Once you've identified the appropriate fastener from the chart on the left, you need to find the correct torque value for that size from the table on the right.

I use this so often, it's posted on the wall in my garage.

Bingo this is the answer! I will print it out and post it in the garage as well. Thanks @Malleus