1930 Model A

[DR]

Hello,

Can anyone give me some ideas on what would cause the front end to shake after going over a manhole cover or a bump in the road. I basically have to stop the car and then proceed from there. I checked the king pins by jacking the car up and they wheel seems like it has no play. So I am not sure if this was a common thing for these cars or not. I am still learning about it. Please advise.

[jkeesey]

Check your shocks, sometimes they also crack the front crossmember which supports the front spring. To test that support the front end on your bumper or frame and lean on one front wheel and see if it moves a lot.

[Ted in MN]

Be certain that the wishbone ball is clamped with the steel retainer not an after-market rubber ball. Also check front wheel bearings and front wheel toe in.

[Tom Endy]

Check your front wheel bearing races. Make sure none of the four races inside the drum is loose on its mount. They should be pressed in tight. A spun race is a common fault. If one is spun you will need to replace the hub.

Tom Endy

[newshirt]

Make sure the pitman arm connection to the sector shaft is very tight. Any slop there can cause this.

[Jerry Parr WI]

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Almost always caused by worn or loose steering parts. Jack the car up by the axle and while rocking the wheel from side to side check for movement in tie rod ends, steering gear and gear mounting bolts. Best with two people. Improper toe in may also cause the problem.

[Jim Parker Toronto]

All of the above is good advise, but you need to go over everything that was mentioned, not just one of them! Jim

PS check the steering box for free play, your steering wheel should only move 1-2" before it contacts the wheels...

[Mike]

Check steering column to frame bolts, pitman arm, tie rod ends, spring shackles, front spring u bolts, and the most over looked item is the SPRING PERCH NUTS,they are always loose.

mike

[Barry B./ Ma.]

I had a loose steering arm (right side) and there was wear in the shaft causing the right wheel to wobble at times and it also loused up the toe-in. I would pull the cotter pins and check the tightness of both arms.

[fordfixer]

Also not mentioned, is the toe-in and toe-out. This will also cause the same issue you describe.

[wensum]

I would suggest putting it on a wheel alignment machine and checking toe-in, castor and camber,
Sometimes it is necessary to fit a steering shock absorber to the tie rod to eliminate this problem.
Wheel balance can affect it too

[FL&WVMIKE]

DR .........................
On my '34, it did the exact same thing. I tightened the tie rod ends by 1/2 turn and it has not done it since.
MIKE

[Tom Wesenberg]

I'm using a very well worn out front end on my 28 while I rebuild the original. I can move the tops of the wheels in and out a couple inches due to worn king pins, but this has never had a hint of shimmy. My friend's 31 Phaeton feels tight on all the front end parts, yet it will go into a wild shimmy when ever it feels like it. I'd say to start with toe in, then camber and caster.

[MikeK]

Even a car with sloppy kings and balls will track straight without shimmy if there is sufficient positive caster as shown below. 80 years of pounding pot holes and RR tracks bends both the axle, shackles, and wishbone in the negative direction. Reducing caster 2 degrees on an A will drive it into a wild shimmy when only one wheel encounters a dip or hole, even if you have new, tight everything in the front end. Think of a shopping cart. When the front wheels get slightly bent back from slamming curbs and lot divots, you get a cart that shimmys.

There is a lot of info out there about how to straighten an A axle, but not much about the wishbone. The front forgings that hold the kingpin actually bend rather easily compared to the axle.

Perhaps someone has the ford print for the wishbone and can throw in a few angles and dimensions?

There is really no mystery. If it shimmys something is usually BENT. Perhaps I should keep my mouth shut. If things get fixed to spec it will kill the market for those band-aid steering dampers.

[Purdy Swoft]

If the frame is sagging at the rear motor mounts it will effect the positive caster