M38 Steering Wobble

[timber21]

Any comments/suggestions on the following issues are Greatly Appreciated, my apology if the issues have already been addressed, but I was unable to locate them; I searched the Forum and did not find the answers I am looking for, so, I am posting them here. I have a M38 that was rescued from being further civilianized years ago; and have been restoring it back to its origin gradually over the years and as funds become available.

The steering wobble is the latest that I am trying to fix. I had some play in the bellcrank and the adjusting screw on the steering gear box had bottomed out. I ordered kits for the 15/16 sector shaft gear box, bellcrank and the drag link.

1- My Ross steering gear box is marked TA122885, the 15/16" sector shaft that I received does not work because the pins are too far apart. I measured the distance between the pins on the old shaft and it is almost the same as the distance between the pins on M38 7/8" shaft. Apparently the kit I received is for M38A1, however, the brass bushings, seal and bearings seem to work, but the cover gasket does not. The M38A1 cover gasket is too large and the M38 cover gasket is too small for my cover. One of the vendors suggested that I heat up the pins on my old sector shaft and rotate them to use the surfaces that have not been used before. Pros, Cons? short of making the gasket, any supplier that may have that?

2- The bell crank kit came with a new bolt/shaft, nut, cross bolt, bearings, bushing and top and bottom seals. My old bell crank shaft/bolt has a dust seal on top of the bell crank that did not come with the new kit, so I used the old one. However, after replacing all the worn parts, there is still some lateral movement in the bell crank, and the main bolt/shaft can still be rotated with some efforts and a 1/2" ratchet. The movement is between the bearings and the new sleeve. One vendor suggested that I add a washer under the main nut, but that is going to put more pressure on the cross bolt and the shaft's shoulder. Any suggestions?

Sincerely

[OKCM38CDN]

Are, you having steering wobble or front shimmy? I ask to be sure... Of shimmy, check your wheel bearings to be sure they are tight. I had that problem, tighten them up then turn the wheels and re-tighten... Also check all components in the steering chain, tie rod ends, bell crank, drag link and steering box. It all adds up and causes problems...

Tie rod ends are not too expensive and when ordering be sure to measure for the proper diameter tie rod pipes (That is what I call them).

Take your time it will pay off

Hope this helps

[wesk]

When discussing front end problems they are usually sorted out to three types:

1 - Death Wobble, Happens whenever you hit a serious bump or railroad
tracks. Causes a terrible left / right oscillation of the front wheels which
can only be stopped by applying the brakes hard. Usually this is a wheel
bearing or king pin (pivot Brg) problem.

2 - Front wheel shimmy, this is a rapid left / right shake of the front wheels.
Usually this is tie rod, bellcrank or drag link problem. Occasionally a loose
steering sector or strg gear box can cause it. And in rare instances worn
or incorrectly pre-loaded king pin (Pivot) Brgs can contribute to it.

3 - Steering wheel play. This is usually the strg gear box and occasionally
the drag link or bellcrank. With wheels on the ground and straight ahead
the strg. wheel should not move left / right more than a 1/2" measured
at the rim of the wheel.

[timber21]

Thanks for the responses, it is the death wobble, it has been the issue since the unit was acquired, wheel bearings were replaced last winter; tie rods are fine. It starts acting up when going over a bump, and shakes the vehicle violently until bringing it to complete stop at which time it still shakes to wind down the momentum. Alternatively, a sudden acceleration would also tame it down till next bump.

Has anyone had luck locating this oddball sector shaft or the gasket for its cover? Or has any experience with rotating the pins? What about taking up the movement in the bell crank shaft?

[wesk]

I think you will find your King pin (Pivot) bearings worn since you have already taken care of the wheel bearings. Jack the axle and see how much top/bottom slack you have. Also check steering resistance of the knuckle (not the steering linkage) using a spring scale with the tie rod disconnected from the arm on the knuckle.

You should probably try to positively ID which steering box you have then try to sort out part numbers.

Take a look at this page in my photo album: http://www.willysmjeeps.com/v2/modules. ... php&page=3

[timber21]

Thanks for the response, king pin bearings are tight, with bell crank disconnected, no movement when the wheels are moved in and out vertically and/or horizontally, most of the slop has been in the bell crank and the steering gear box. Also unlike other numbers that are part of the castings, this number TA13084NG is engraved on the sector shaft's housing where the bearing surfaces fit. I am attaching a few photos to aid in ID. Sincerely

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[wesk]

Photos did not show up.

Thanks for the response, king pin bearings are tight, with bell crank disconnected, no movement when the wheels are moved in and out vertically and/or horizontally,

And what tension is on the knuckle steering arm?

[timber21]

Thanks again, will check the preload as soon as I find a fish scale. Do the photos have to be loaded from a photo gallery album or I could load them directly without having an album? I do not have one.

Sincerely

[wesk]

Yes this older format Phourum program does not allow loading files directly from your computer.

We can solve your photo hosting issue right now:

Here's your album:
http://www.willysmjeeps.com/v2/modules. ... _album.php

Here's the rules:
http://www.willysmjeeps.com/v2/modules. ... opic&t=498

Here's the tutorial for loading your album:
http://www.willysmjeeps.com/v2/modules. ... _album.php

Here's the tutorial for posting your photos:
http://www.willysmjeeps.com/v2/modules. ... pic&t=8670

[timber21]

Thanks again, here are the photos, sorry, they are slightly over the size limit, will try to reduce them soon.

[wesk]

Your steering gear is the late M38 gear box used on MC31337 and up. It's part numbers are: ORD# 7412447, WO# 804384, RG# TA13084. It is well illustrated in the M38 Parts Manual ORD 9 SNL G-740 page 259 and you will find it's actual listing with part numbers on page 265. Also the assy number is on your 3rd photo.

(ORD is Ordnance, WO is Willys Overland, & RG is Ross Gear)

The correct sector shaft for your box is PN WO# 804534

The correct cover gasket is ORD# 7375346, WO# 644537 & RG# TA129000

The two above parts are different on the M38A1 box and have different part No's

[wesk]

Those last 2 photos are your thumb nails which make up the index page of your photo album. Left Clicking on them once would have yielded the small sized photo like the two I posted. Those sized photos (#1 & #2 above are only in the 50K file range which is a 100K smaller then required.

[timber21]

Thanks again, photos were corrected, will have to find the correct shaft and gasket to put it back together; and deal with the bell crank movement.

[wesk]

Google this: "M38 sterring Bellcrank willysmjeeps"

You will get a lot of mjeeps posts on this exact issue.

[dpcd67]

I had to remove all the shims in order to get the correct king pin preload. And that is with new bearings and cups.
Check that, and your toe in because the wobble is related to those things.