Front axle - bearing preload

[idiocrates]

I think I've found another exercise in patience......setting the kingpin bearing preload on the steering knuckles of the front axle. Now I have a quick question........I have a Jeep Universal Manual as well as an 8014 Maintenance Manual. The Universal Manual says the preload is correct when a pull of 12 to 16 pounds on the steering arm starts the flange moving. The 8014 manual says the preload is correct when a pull of 6 to 9 pounds starts the flange moving. So which is correct? I was able to achieve the 6 to 9 but I doubt I can remove enough shims to get to 12 to 16......and man, that would be one tight flange it seems to me. Also....once the number of shims is determined.....do I need to remove the two kingpin bearings and pack them with grease before the final installation? Any and all suggestions will be greatly appreciated. Thanks.

Jim

[davem201m38]

Hi, yeap I was surpised by the figures in tm 9-1804b page 138. The 6-9 pounds figure didn't mean much to me till I set it on the force meter because it works out at about 30-40 Newtons of force to get the knuckle to turn which did seem a lot.

Still, that's what the book says and it's never been amended so after 60 years it must be OK.

That higher figure you've got (sorry don't have th Universal jeep manual) seems really high, around 48-64 Newtons! guess it helps keep it in a straight line with a mid mounted Massey Harris finger bar mower !!

If it's an unadulterated M38 I'd stick with the books for that jeep and ignor books for a jeep you don't have.

[skyjeep50]

I packed the king pin bearings before assembly and pre-load testing. It does seem to be a lot of resistance but that's what prevents front end shimmy and the steering system has a lot of mechanical advantage when the wheel is turned. I set my pre-load at 12 lbs in my M38 and CJ2A/M38 and called it good.
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1951 M38

[idiocrates]

Thanks for the replies. I went ahead and went with the 6 to 9 like the TM9-8014 Mainteneance manual calls for......and I'm glad I did. After putting on the three piece rubber oil seals its almost impossible to turn the knuckle by hand. I can't even imagine being able to move the flange had I used the higher preload numbers from the Universal Jeep Manual. I packed my bearings after setting the preload but I found no difference when I checked it afterwards. The only other problem I had was getting the three piece seals on after installing the kingpin caps. One of my brake line guards has four holes in it and it interferes with the installation of the top two bolts on the oil seal. It was necessary to back off the outside two bolts on the cap and remove the inside two bolts so that the guard could be tipped up out of the way. Once the top two bolts were started in the seal I reinstalled the kingpin cap and guard.

One last quick question.........which side of the vehicle gets the hub with the left-hand threaded lug bolts?

Okay....nevermind.....I found the answer.....left hand thread on the left side. When I did a search of my pdf manual I just assumed they would use terms like left-hand and right-hand.......never occurred to me to look for clockwise and counter-clockwise. Got it now.

Thanks,
Jim