Front End Shimmy

[BigErn]

The past few weeks (when it has not been raining) my pretty new to me '28 developed a front end shimmy problem. I jacked it up and could not see any looseness in any front end parts when I wiggled the front wheels, but I could barely feel a slight "tick" on both wheels when I wiggled the wheel from top to bottom. I tried tightening the bearings and it seem to help for about 200 yds then the shimmy came back. If I hit a small pothole or bump (which is unavoidable in this area) at maybe 10 or 15 mph or higher it will start to shimmy and not stop until I slow to almost a stop. I have not had a chance to actually look at the bearings but I am suspecting that they may be the culprits. The wheels to spin okay without grinding noises or roughness. If it did not do it before, so it seems like caster would not be the problem (unless someting changed) . Any thoughts before I start tearing things apart? By the way, this is my first experience with a front end problem.

[FL&WVMIKE]

BigErn ........................
Naturally, there are several things that can cause this.
I had the exact same symptoms in my 1934 Ford. I tightened each tie-rod end, one half turn, and my problem went away. I was lucky.
MIKE

[kp]

In the old Days ,when front end shimmy occurred ,which happened frequently,we would jerk the steering wheel one way and then back the other real quickly to stop the shimmy,most of the time it would stop shimmying immediately,til the next chunk whole or bump ,I too had a 34 ford that would shimmy something awful . all the tie-rod ends were worn out. My 31 doesnt shimmy but it will "hedge hop" on the country roads which requires both hands on the steering wheel and dont look off .

[Patrick L.]

There has to be something loose.. Check everything thing from steering wheel free-play, thru the steering box mounting bolts, drag link and tie-rods.. Also check the radius rod under the flywheel housing..

[BILL WILLIAMSON]

Shimmy is usually caused by slack or looseness somewhere in steering linkage, Pitman arm clinch bolt, steering gear box slack , etc. With wheels on the ground, have someone wiggle steering wheel back and forth while you ckeck everything that moves. Mine was caused by a broken spring in the rear drag link end. Tighten pitman arm clinch bolt very tight, also tighten steering box to frame bolts very tight also.

[James Rogers]

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Check your toe in.

[mantta]

I went through the whole front end on mine and it still had a shimmey. I found out that the wheels were towed out instead of towed in. I readjusted the tow in and it drives like new.

[pat in Santa Cruz]

this is a common subject here. Search the archives for lots more discussion. Essentially, you need to find the looseness, most commonly in the pittman arm, loose steering box bolts, too much play in the worm gear or a bad after-market rubber ball on the radius rod ball. If you have that rubber thing, get a new Ford style radius ball kit and replace it. But any loss of motion at any point in the steering can cause it. A small click in the king pins is probably not it.

[Fred K-OR]

Due to the fact it seemed to have happend after you drove it for a period of time, could it be one of those little "cup" things in the tie rod ends finally wore out? I took one of my tie rod ends off and found that there was almost nothing left of this "cup" thing. Just a guess from a guy that knows little about this sort of thing.

[Ron in Quincy]

As previoulsy said, check drag link and tie rod ends; there should be about a 25% load on the springs; if you find this OK, check for a bent axel up or down at one end or the other; this can effect camber and can cause a shimmey; more so when the tires are inflated to their 35 lbs. of pressure.

Ron

[BigErn]

Here is an update on the shimmy problem. I finally had time to jack up the front end (on the frame). Everything was tight except the steering gear box. With my wife holding the steering wheel steady, I could move the front wheels significantly side to side. All of the slop was at the sector shaft and unfortunately the pitman arm was tight on the shaft. The pitman arm would move 10-15 degrees. Of course I turned the only knob I had (the section shaft trust screw) and it not suprisingly did not help. So, now I am thinking that I needed a gear box rebuild. Does it sound like I am on the right track?

[BigErn]

Forgot to mention that it is a 7 tooth gearbox if that makes a difference.

[Glenn C.]

Yes.....minimal adjustments. Convert to the Gemmer 2 tooth design, or go for the F150 conversion. Be happy and safe.

[allford]

Check the toe in..it only takes a few minutes and this adjustment may solve the problem. If you have the toe out, instead in, sure will shimmy.

[J Franklin]

Check that the spring shackles are free and not binding.

[Purdy Swoft]

I set the toe in on my model A at 1/16 plus or minus 1/32. Improper toe in is usually what sets up shimmy and anything loose about the front end and steering will contribute. If the air pressure is low in the back tires this can cause shimmy. If the front spring is worn and sagged (usually on the drivers side) This can cause shimmy.

You mention adjusting the steering. You need to jack the front wheels off the ground. Tighten the sector thrust screw and slightly back off. Turn the steering all the way both ways and check for bind. If it binds you may have to back off more. The next adjustment is for worm gear end play. While sitting in the drivers seat, grasp the steering wheel and push foward and then pull back. If any movement foward or backward is felt, you will need to remove shims at the end of the steering shaft. To remove shims you will need to remove the light switch and spider. You will then need to remove the four bolts at the bottom of the column, I think they have 7/16 heads. After the four bolts are removed the end of the steering housing will slip right off. You should find a stack of metal shims between the steering column and the end housing, like gaskets. Removal of shims will reduce end play, it will be trial and error untill you remove enough shims. The object is to remove as many shims as possible without creating bind. with the front wheels still off the ground, turn the steering wheel from one end to the other and if bind is detected you will need to add a shim or two to relieve the bind. After these adjustments are made let the wheels back down for the next test. Watch the square sector shaft where it enters the pitman arm. Have someone move the steering wheel slightly from one end of the free play to the other. If the slightest movement is detected between the sector shaft inside the square opening in the pitman arm, you will need to remove the cotter pin and tighten the hell out of the pitman arm bolt. The slightest fraction of movement between the sector and pitman arm will end up as inches of slack at the steering wheel. Try it you may be surprised at the improvement.

[walt jones]

I had the exact same problem. I was able to stop the shimmy while driving buy doing as KP above suggested but had to repeat the procedure each time shimmy started. Upon close examination I found the pitman arm tightening bolt very slightly loose, I tightened it. The radius ball was also loose. Examination showed that it had very little wear. I tightened it up as far as the nuts would go, that is up to the spring spacers. Doing one or both of these actions seemed to cure my shimmy. If your radius ball is warn you can cup out a fender washer and insert it into the ball cup. This sometimes helps. All other suggestions above are good ones as the shimmy may be caused by a variety of problems.

[leadpot]

Just my 2 cents - had the same problem at low speeds, would have to come to a complete stop. Couldn't find any issues with the front end. My 16 year old Allstate tires with still good tread were hard and had lost their flexibility. Put on new set of Firestones and has never happened again - just something to consider.