I replaced the front hub on my kids XJ 99 today..manual says 275lbs. torque on the front hub nut...Has anybody done this..my 1/2 in Torque wrench only goes up to 150lbs. I cranked it on with a breaker bar and a piece of 5 foot pipe.Do they even make a torque wrench that goes that high..?

 

Check that torque spec, I say 175 ft lb torque on the front axle nut to retain in the bearing hub. Do them lots. Yes there is a torque wrench that big. Use a 4ft Matco torque wrench at work for this applciation. 275 is Too High!

 

Book said 275...I thought that was crazy...I think I almost pulled my shoulder out freeing it up.Took me a couple of hours...I only replaced the passenger side but I think I should do the other one too.How long do they usually last?

 

you got it mixed up with NM.

MODEL 30 AXLE
DESCRIPTION....................................... .........TORQUE
Fill Hole Plug ...........................34 Nm (25 ft. lbs.)
Diff. Cover Bolt ........................41 Nm (30 ft. lbs.)
Bearing Cap Bolt .....................61 Nm (45 ft. lbs.)
Ring Gear Bolt .............95-122 Nm (70-90 ft. lbs.)
Shift Motor Bolt .........................11 Nm (8 ft. lbs.)
Axle Nut .................................237 Nm (175 ft. lbs.)
Wheel Brg. Bolt ......................102 Nm (75 ft. lbs.)
Lower Ball Stud.....................108 Nm (80 ft. lbs.)
Upper Ball Stud .....................101 Nm (75 ft. lbs.)
ABS Sensor Bolt ......................11 Nm (96 in. lbs.)

 

x2 on what defiance says. i just did it a couple days ago so it still fresh in my head the axle nut should be 175 ft lbs

 

175 foot pounds of torque for that axle nut although I been in countless garages repair shops in my town and have never ever saw they first mechanic torque one of those axle nuts wirh torque wrench they just gun em down with an impact wrench and send em down the road.

 

I run mine at 150 so when if i pop a shaft I can get it undone on the trail 275 is way too tight

 

not long at 275.
i buy the skf bearings and usually last a few years with my heavy rims/tires.
but it's only my trail rig and doesn't get much street use. and only summer driven.

 

X2 with Caged on buying the SKF brand part. Buy the good wheel hub. I've seen the junk fail within a week on various brand applications, not just jeep. Sure the parts warrantied but not the labour costs.
I'm runnin 180000km on my hubs across one set of 235's and one set of 31's, just starting to get a strange feel on one, will plan to replace in couple weeks with warmer weather, but come on you can't get that kind of mileage on parts delivered within a container full of junk. Pay a little more for the premium hub. It will deliver satisfaction.

 

Wha?

The hub bearing retainer screws get torque to 75 pound-feet, and the stub shaft nut gets 185 pound-feet, per most year FSMs.

You can "extend" the capability of your torque wrench through the use of various lubricants - for instance, if you use never-seez on the threads, you can reduce the installation torque by half to achieve the same preload as the "clean, dry" manual spec. I know this works - it's how I do it (my 1/2" drive torque wrench tops out at 150 pound-feet as well.)

 

Using lubricants only help to get more accurate torque readings. Using anti-seize may make a few pounds difference but not enough to lower the torque setting. I always tighten axle nuts with an impact gun. I've never had any failures and I can guarantee that I've installed a few hundred hub assemblys and wheel bearings over the last few years.

 

no

 

Oh yeah! We just had one sent out and re-calibrated for a customer that goes 90-600 Ft/Lbs.

 

Yes; per manufacturer literature, fastener industrial documentation, and experimentation.

Recall that the purpose of "torquing" a screw isn't putting a specific torque (turning force) load on it, it's to put a specific tensile (stretching) load on it. Measurement of the force needed to turn the screw is an indirect mean of measuring that tensile loading.

There's a very good reason that performance aftermarket connecting rod bolts and nuts don't come with a torque specification - they come with a stretch specification. And you can get a "rod bolt stretch gage" - it's set to zero with a resting bolt, you put a box wrench on the hex, and you turn the nut until you get that specified stretch value.

Direct measurement of bolt stretch is the most reliable means of establishing and measuring tensile preload, since yo're measuring it directly.

The torque (turning force) required to attain a certain tensile load will decresae as the threads are lubricated relative to the "clean, dry" specification given in the manual. The amount that the applied turning force is to be reduced is determined by the lubricity of the applied compound - starting with threadlocker compounds at "0% adjustment" (they're not lubricants, and they're formulated to not change the Cf between the thread surfaces.)

Yes, cleaning and lubricating the threads will also allow for more consistent application of tensile preload, but that is not the only effect.

Conversely, if you do not clean the screw threads or the holes, you'll end up applying less tensile preload to the screw/bolt shank for the same "clean, dry" torque value - because the friction between the thread surfaces is greater. There's no set definition for how much of what will reduce the tensile loading by how far, but it's not a situation where the values would need to be known anyhow (use a wire wheel to clean your screws if you have to, and making a set of thread chasers in the shop is a simple process with a Dremel or other thin cut-off wheel, a high-speed spindle, and a set of hardened screws. Cut three or four flutes longwise across the threads of the screw, and back it out to clean the flutes out every 2-3 turns to remove accumulated crud. You use screws so you can't cut new threads and screw up the hole, but you can purchase purpose-built thread chasers. But why? They're cheap and easy to make in the shop.)

Rumour has it that newer never-seez compounds are formulated to prevent seizure and to not lubricate the threads in so doing, but I will believe that when I can turn up information from the manufacturers. The last manufacturer information I have is to reduce "clean, dry" torque by half - this from two or three different reliable manfuacturers (one is Permatex/LocTite, the other two were sold to me by MRO houses.)

As far as "high-load" torque wrenches, I think the highest I'd seen was a 1' drive job that went up to 500 pound-feet...

 

I read it is 14 ft pounds ...dude...275 will crush the wheel bearing