Shimmy/steering issue

[Scott in NM]

Ye olde jeep was beginning to shimmy on its own accord doing 40-45 mph. Disassembled right front axle and readjusted the flange caps per the manual. Reassembed same. Shimmy now gone, but can only turn left two spokes of the steering wheel vs four for a right turn. Didn't do nuthin' else, I promise! So what did I do wrong?

Also, I was originally planning on disassembling both sides of front axle, but shimmy is now gone and I sure don't want to fix somthing that isn't broken. Should I just hold off tearing apart the front drivers side axle to see if the shimmy returns, or assume that the problem was on the passenger side? Anyone have a recommendation to pull the left side apart just because I have nothing better to do for three hours? Any and all inputs greatly appreciated, thanks!

Scott

[cjv-35]

Just wondering.Did you mess with the tie rod end on that side?

[Cuz]

Flange cap adjustment concerns adding or removing shims under the cap for proper support of the drive axle and should have nothing to do with wheel shimmy or steering shimmy. Let us know what items you actually adjusted.

[Ben Dover]

We may have a terminology difference here.
Question, did you remove the knuckles and inspect the bearings and their races? If you did not and just removed the steering knuckle bearing cap and removed a shim or two to tighten it up may be the problem. If the races are grooved(this does happen after many years of use the bearings pound little vertical grooves, a condition called "brinelling", which mar be what is causing your difficult steering.
Most Shimmy in Jeeps is caused by worn steering knuckle bearings with a bit of wear in other front end components mixed in.

[Scott in NM]

1. Didn't touch tie rod end other than to disengage it from the flange arm.
2. Jeep steering was smooth and symmetrical before I “fixed” it.
3. I did not inspect the steering knuckle bearings. Not a formally trained mechanic, I looked at the diagrams and failed to notice these in the exploded diagram.

OK, looks like I need to go back in and inspect the bearings (I assume the bearing cones, 705381? Dang, I hate gobs of grease!) If I need the bearings, are they a stock item at NAPA or somewhere, or do I need to go somewhere special?

Still makes me wonder why the steering is now so different. I shall look at this during reassembly after the bearings inspection.

Looking for any and all tips, suggestions, recommendations, hints, and clues. Don't want to go back in after this next time!

Scott

[Ben Dover]

I had a suspicion that this is what was done. You need to remove the Wiper Seals, the Bearing Caps and remove the steering knuckles. The Races are Timken/BCA 11520, Cones are 11590. If you are lucky, you may be able to reassemble it with new bearings and use the original shim packs provided you can tell which side you previously removed them from. To do the Job properly, you should buy some NOS Shim packs to have on hand so that you may be able to select the correct thicknesses to arrive at the proper preload. This is a precision job and must be done according to spec. It will be good for another 20+ years when done correctly. The chances are that your races are grooved and pitted and the bearings will show water damage and pitting. The job is much easier if you have a 0-1" Micrometer so as to be able to determine the difference between the shim thickness as the shims range from 0.030", .010", .005" and -0003". Having the micrometer will allow you t precisely select a thickness to fine tune the preload or drag. It is important to start off with the thickness of shims recommended in the TM9-8015-2 ORDNANCE MAINTENANCE, Power Train, Body and Frame, M-38A1. It is a good investment. If you do not have this manual, you should as it will explain the proper procedures.

[Ben Dover]

[quote="Cuz"]Flange cap adjustment concerns adding or removing shims under the cap for proper support of the drive axle and should have nothing to do with wheel shimmy or steering shimmy. Let us know what items you actually adjusted.

[img]http://willysmjeeps.com/v2/modules/gallery/albums/album90/207_G.sized.jpg[/img]

[img]http://willysmjeeps.com/v2/modules/gallery/albums/album90/210_G.jpg[/img][/quote]
______________________________________________________________________________________________________________
And Cuz, thanks for the excellent Graphics.

Just a reminder, tho, the "Steering Knuckles with Arms" do have a proper NOMENCLATURE, they are listed in TM's and SNL's as FLANGE, Steering, left, w/integral arm (knuckle and arm) and FLANGE, Steering, right, w/integral arm, (knuckle and arm), the upper and lower caps for same have correct terminology (Nomenclature) CAP, steering knuckle king pin, welded assy.
Correct M-38A1 Terminolgy goes a long way to putting everybody on the same page and makes repair tips a lot easier...

[Cuz]

Joel said: Just a reminder, tho, the "Steering Knuckles with Arms" do have a proper NOMENCLATURE, they are listed in TM's and SNL's as FLANGE, Steering, left, w/integral arm (knuckle and arm) and FLANGE, Steering, right, w/integral arm, (knuckle and arm), the upper and lower caps for same have correct terminology (Nomenclature) CAP, steering knuckle king pin, welded assy.
Correct M-38A1 Terminolgy goes a long way to putting everybody on the same page and makes repair tips a lot easier...

Are you saying I did not properly identify something? I made no mention of these parts you are listing as improperly described. Have you confused me with another post somewhere?

[Ben Dover]

Well, Cuz, It does appear you were confused, as you have prominently displayed the instructions and diagrams for installing the shims under the Front Axle Drive Flange. Your statement "adding or removing shims under the cap for proper support of the drive axle and should not have any thing to do with wheel shimmy" certainly indicates that you were confused.
You will note that Scott removed some shims on the steering knuckle caps, not the drive flanges.

[Scott in NM]

Gotta' love a good discussion!

Fortunately, I have a micrometer good to 0.0001", so shim thickness is no problem. I shall follow the advice of y'all and start the rebuild when I get a little more time. Meanwhile, I did some troubleshooting on the steering issue. I disconnected the tie rod (after jacking up the vehicle), and still had the problem. Issue now NOT in steering, but in the axle. Took axle assembly apart one more time, noting if steering changed with each part removal. Got down to removing the brake drum assembly, and lo and behold, one of the six bolts was about 1/4" longer than the others. Apparently I put them back in a different constellation that when removed so now the long one was hitting up against something inside preventing a full left turn. Replaced bolt with one of proper length, issue resolved. Put everything back together and steering back to its sweet little self.

Apparently bolts are like bullets - It's the one you don't see that gets you.

And to clarify the nomenclature, mine is an M38, not an M38A1. Turns 60 in a few days. Who would have thought that something this old can function as well as it did when new (shimmy is a minor tweaking, wouldn't even attempt it on the Toyota hybrid Highlander)? Don't build them like that anymore!

Scott

[Ben Dover]

You are saying that a backing plate bolt was too long?

[Cuz]

Scott,

Sorry for the drifting conversation but this guy always plays this game.

In Scott's opening post he said:

readjusted the flange caps

In my post I asked if he was adjusting shims under the axle driving flange cap which by the way is exactly what the manual illustrations calls it "DRIVE FLANGE CAP and was what Scott's post sounded like to me.

The act of shimming for those two locations is "Under the drive flange cap" for the axle shaft and "Under the pivot bearing cap" for the pivot bearings. None of the manuals use the term flange when referring to the shimming of the pivot bearings.

My post asked for clarification of the terminology and offered a quick manual view of the only "Flange cap" that gets shims on the outboard ends of the front axle.

Scott then replied and clarified it was the King Pin /Pivot bearing Cap shims he had adjusted. Which by the way is exactly what the ORD 9 SNL G-740 calls those shims "Shim, king pin bearing" on page 222 and also the M38 TM 9-1804B Power Train, body & frame manual calls them just Steering Knuckles. This TM also overlooked the axle shaft shimming which was published in a 1951 issue of the PS magazine.

I clearly understand and am thoroughly familiar with both shimming procedures.

Scott,

Again I apologize for the drift from your post's topic but I get very tired of folks that try so hard to find things wrong with a post they often end up inventing the error themselves.