Shake or Wobble at Downhill Stops

[Fillinjc]

Hello,

1930 coupe.
I experienced something yesterday that I haven't felt before. Just achieved break-in of my freshly rebuilt engine at the builder's recommendation of 500 miles. Came to the first stop sign which I stop at every time I leave my house. Downhill stop sign and the car produced a rather extreme shake or wobble. I continued on with no issue until braking on the next downhill and got the same wobble. Turned around. Started back home. Couldn't reproduce it so went back to the downhill and wobble. Watching the gear shift lever, it seemed like the drive train was shaking but now I'm thinking that was probably coming from the front cross member. Crawling under the car today I see coolant dripping all over and I had to top off radiator for the first time but I'm guessing that is due to the hoses being jarred.

I took the car out for a short bit tonight without floorboards so I could try to see what is happening but couldn't reproduce it. Honestly I was pretty cocky yesterday after driving 500 miles and thinking that I could now drive it more aggressively. And today back to babying it.

Any thoughts?

Thanks,
Jerry

[1crosscut]

Have someone sit in the car and bump the steering wheel back and forth over and over just enough to just start to move the wheels. Lay underneath and look everything over to see if there is any slop in the steering assembly. Tighten anything loose.
Jack up the front end and grasp the tires and wiggle them top to bottom and side to side to see if you have loose bearings, backing plates or worn king pins.
Pull the wheels and hubs and give the brake system a good look over.
Check your ball on the wish bone to make sure it is adjusted right.
Lots of things it could be.

[Jwilli]

Had that problem the front tires were simply underinflated. Hopefully you just need some good air.

[Fillinjc]

Thanks! I will check everything listed above.

One thing I just thought of is that before I took the coupe out yesterday I greased it as a 500 mile service. In doing this I saw that there were broken grease fittings at the top of the front spindles. I pried out the broken fittings, dug out some crud and greased with new fittings. The first time in God knows how long that there is grease there. Might have freed up some worn bearing surface?

Thanks,
Jerry

[heneste]

Don't forget to check toe-in adjustment also.

[Mitch//pa]

Sponsored Links (Register now to hide all advertisements)

Do a search "death wobble".

[SeaSlugs]

yea, should be space between the 2 pieces that go around the wishbone ball assembly on the bellhousing - no space major slop. or of the bolts are "too long" and nuts bottomed out. Those holes in the soft cast iron get hammered out pretty bad over the years.

[Synchro909]

Originally Posted by Fillinjc

Thanks! I will check everything listed above.

One thing I just thought of is that before I took the coupe out yesterday I greased it as a 500 mile service. In doing this I saw that there were broken grease fittings at the top of the front spindles. I pried out the broken fittings, dug out some crud and greased with new fittings. The first time in God knows how long that there is grease there. Might have freed up some worn bearing surface?

Thanks,
Jerry

Badly worn king pins could cause the problem but so could lots of other things. Check everything as was described above and do the search suggested. Loose bolts holding the steering box to the chassis is another cause.

[goodcar]

The July/August 2015 MAFCA Restorer has a very good article, "Causes and Fixes for Death Wobble in the Model A Ford"

[3.6rs]

Originally Posted by Fillinjc

Hello,

... Honestly I was pretty cocky yesterday after driving 500 miles and thinking that I could now drive it more aggressively....
Jerry

You drove 500 miles yesterday ?

[TerryH]

I think he drove the 500 miles earlier, and was feeling cocky yesterday.....that's the way I would interpret it.

[Synchro909]

What's wrong with driving 500 miles in a day? I've done 700.

[3.6rs]

Originally Posted by Synchro909

What's wrong with driving 500 miles in a day? I've done 700.

Nothing, but if you keep "turning around" and "going down the hill" again you are going to sleep well after that day. Or don't sleep at all and keep wobbling in your bed...

[BILL WILLIAMSON]

Originally Posted by heneste

Don't forget to check toe-in adjustment also.

How LOOOONG a string do you need, to check the TOE-IN????
I know I have it in my notes, somewhere
Bill W.

[Terry, NJ]

It sounds like you have the beginning of "Death Wobble"! It doesn't fix itself! Jack up one front wheel at a time and shake, beginning with the left side. Also disassemble the steering balls (Linkage) and make sure they're round (1.000"). This is just a start, almost any worn part in the front end will cause death wobble from a bad steering box to loose king pins, from worn out spring bushings to bad tires and beyond.
Terry

[Fillinjc]

Hah, drove it 500 miles this past season to break-in the engine per instructions from Schwalm's. Saturday I put on only about a mile and a half due to the issue. I will check everything I see listed here and search "Death Wobble". I do know that I need to rebuild the steering arms. Balls are not round. I have installed a Mel Gross steering box and everything has been replaced up to the steering arms. They are next for refurb.

Thanks for the help.
Jerry

[SeaSlugs]

probably kingpins and bushings too...DO NOT put the bandaid fix of a "steering dampner" the parts houses sell...replace your worn out stuff and it will be perfect.

[KGBnut]

I agree, check for undo looseness everywhere, but odds are pretty good that it is kingpins. I did mine a few month back. It is not a difficult job, but it is a heavy job.

Another thing worth checking...if your radius ball was 'upgraded' to the rubber ball type, you may have a worn out rubber ball. If that is the case, I would recommend that you change it back to the original setup.

Good luck,

Ken

[H. L. Chauvin]

Why beat around the bush.

Your reply no. 4 is about as informational as opening an Egyptian Tomb that has been sealed for years ..... broken grease fittings, crud ..... King Tut, Julius Caesar, or Christopher Columbus may have been the last guy to grease and maintain your Model A front end.

If it were mine, rather than shimmy and wobble all the way into the front bumper of an oncoming 18 wheeler, I would conduct a thorough Archaeological Investigation on the entire front end.

Rather than considering this reply #4 as a problem ...... consider it a challenge ..... and just get a Frank Buck Hat and start digging.

For life safety's sake, hope this helps.

[DJ S]

Originally Posted by H. L. Chauvin

Why beat around the bush.

Your reply no. 4 is about as informational as opening an Egyptian Tomb that has been sealed for years ..... broken grease fittings, crud ..... King Tut, Julius Caesar, or Christopher Columbus may have been the last guy to grease and maintain your Model A front end.

If it were mine, rather than shimmy and wobble all the way into the front bumper of an oncoming 18 wheeler, I would conduct a thorough Archaeological Investigation on the entire front end.

Rather than considering this reply #4 as a problem ...... consider it a challenge ..... and just get a Frank Buck Hat and start digging.

For life safety's sake, hope this helps.

I couldn't agree more. Do a thorough investigation and fix EVERYTHING that needs attention.

[Fillinjc]

Practically new Firestone tires. Pressure is 32 psi, down a couple pounds but I would think not bad enough to cause this. I got the coupe with the rubber ball wishbone setup but missing the rubber. A thick layer of grease in it's place. I did replace the rubber ball and made sure it was together correctly. I was hoping to drive longer this season but I guess it's time to tuck the coupe into it's winter corner of the garage and start the next list of refurbs. Front end top of the list.

Thanks again.
Jerry

[H. L. Chauvin]

Hi Jerry,

Your rubber ball set up with grease replacing a worn rubber ball says just a little more about the character of the previous owner ...... he may have been a fine gentleman, but Model A repairs were just not his thing ..... bless his heart, he did not ask a junk man to pick it up.

The front end is not that difficult to restore .... if you keep in touch & ask Forum questions it can be done one (1) part at a time ...... many compassionate people here willing to assist.

If your garage is unheated .......... and ........ if you just first thoroughly clean off all of the grease .................. in winter time, Model A front ends fit well in a heated Living Room or Den.

My early 1930 Coupe is dismantled ..... been having it 58 years .... I need to get busy also.

[Terry, NJ]

Jerry, the most likely way to find find the problem(s) is to jack up the front left wheel and shake it in all it's planes. Fore and aft, up and down, in and out with the right wheel pinned to the floor. Check the king pin and other points of movement. Round out, with a file, any possible out of roundness (.020-.030 max) of the ball connections. Check the pitman arm for looseness on the square shaft coming out of the steering box. Check the wheel bearings for looseness. One unlikely place to look is the spring shackle bushings. On my car, the spring shackle bushing were so worn the I had to replace the spring perches with the bushings, but it stopped the Death Wobble (in my album "My Coupe") Another place to look is the steering box adjustments (4). Too much slop in the steering gears will cause death wobble too. Or a combination of one, two, or more of these problems will cause D.W. also.
Terry

Originally Posted by Fillinjc

Practically new Firestone tires. Pressure is 32 psi, down a couple pounds but I would think not bad enough to cause this. I got the coupe with the rubber ball wishbone setup but missing the rubber. A thick layer of grease in it's place. I did replace the rubber ball and made sure it was together correctly. I was hoping to drive longer this season but I guess it's time to tuck the coupe into it's winter corner of the garage and start the next list of refurbs. Front end top of the list.

Thanks again.
Jerry