DEATH WOBBLE

[lincolnuT]

Always start with the tires first, Yes, sorry I just thought if you were putting a car back on the road after some years of it sitting you would put new tires on it.......If the car has been sitting a long time then you should replace the tires before you do anything.....Tires are like many other things on a car they don't like to set around and develop flat/bad spots.....Then just start doing the rest.......

Mike

 

[EX JUNK]

I agree with looking at the tires first, especially in this case because the car sat for so many years before it was bought.

Jim

 

[TriodeLuvr]

Have to ask, is this a left/right wobble or is it actually wheel bounce? I fought the latter for quite a while. Cured it with hydraulic shocks and truer wheels and tires. FWIW, my toe is set in, not out.

Jack

 

[luke 13]

anyone have a suggestion of new tire size?

 

[luke 13]

its a wooble but while im going down the road I can see the tires are out of round. I can see they are going up and down. like being slightly oval instead of dead round.

 

[EX JUNK]

anyone have a suggestion of new tire size?

It all depends on the look that you want to attain. On my car, I'm running 155/80 x 15" on 4" wide rims.

Jim

 

[tompen]

its a wooble but while im going down the road I can see the tires are out of round. I can see they are going up and down. like being slightly oval instead of dead round.

Just my 2 cents. If you're front tires are hopping like a basketball you might try checking the runout and tread deviation by putting the tire on a spin balancer. If they have up-down runout we used to break them down and rotate the tire 180 degrees on the wheel and rebalance.
I had the same problem and all I did was tighten the friction shocks and it almost eliminated the problem. I think it is worse because we can see them so clearly. Good luck.

 

[hulkamania]

We just finished a car up and it had the wobble. I brought it back and adjusted the toe in a little more, lowered the pressure in the tires to 20 pounds and made sure everything was tight and it fixed the issue. Then I came back and added a steering dampener for added protection.

 

[edski]

hello, new here, been interested in do - it - yourself cars forever it seems--loved six cylinder stuff, so nearly always had to home make nearly everything- am now probably into last, and most elaborate project of my life (its only a homemade C-cab) but the largest and only ground up endever I've ever undertaken. But am loving the research and the wide array of how to do every thing involved

Edski

 

[tompen]

hello, new here, been interested in do - it - yourself cars forever it seems--loved six cylinder stuff, so nearly always had to home make nearly everything- am now probably into last, and most elaborate project of my life (its only a homemade C-cab) but the largest and only ground up endever I've ever undertaken. But am loving the research and the wide array of how to do every thing involved

Edski

Hi Edski, Welcome to the forum. How about jumping over to "introductions" and tell us about yourself. More people will get to know you there.
Tom

 

[edski]

oops wrong place for that introduction--sorry--still new here.
You said this shake can be started sometimes by hitting a bump--this makes me think that perhaps you have a lot of positive caster in your set up--this is like the excess caster you see in a shopping cart--and like on an old VW beetle (they had quite a bit of positive caster and the factory had to add a "shock absorber" to the tie rod to dampen this shaking. When that steering dampener wore out -- going over a r.r. track would kick off a terminal front wheel shake to where you couldn't hardly hold on to the steering wheel! Caster on one of our t-buckets helps them head straight on the highway--but too much can lead to these shakes. Caster is pretty hard to measure without going to a front end shop. You could try installing some 2-1/2 degree caster shims (pointy end pointing FORWARD) to DECREASE the amount of caster pretty easily--kind of a trial and error deal--fairly cheap. Front end shops that deal with straight axle front ends might have them laying around (almost all chevy pickups had them thru 1960--others too)--on a typical t-bucket with a transverse front spring you would only need one. Of course there aint a lot of young techs that ever dealt with anything from that far back into the last century, and they may not have ever heard of one of these shims. They were usually used to INCREASE the front caster on the old Chevys--but there is no law that says you cant reverse their position in order to DECREASE the caster--its cheap! (and easy). Thats my two cents----Another OOPS--this only cocks the spring--on most t-buckets the front radius rods actually dictate the caster angle--depending on their design--if its a two separate rod radius set up-then you will have to lenghten the top one (or shorten the bottom one) to actually change the "tilt" of the axle. if its a wishbone, then you will have to raise the rear pivot at the chassis (not as easy--new hole if you have the room or a new mounting plate may be required.
Edski

 

[Robert]

Yep, it's called shimmy.

Speedway motors has a good FAQ on how to eliminate it.

I set toe out 1/8th inch, all steering joints seem pretty tight - - reverse corvair gearbox giving me fits as I've tightened it up like 3 X and it still keeps loosening up some each time.

Concerned about getting gearbox too tight as that can ruin the brass worm gear.

Found the reverse corvair gearbox had only a small amount of white lithium grease in it - - so I mixed 90 wt gear oil and moly grease and injected it in till overflow.

Wheel bearings all snug.

I get shimmy only on certain road surfaces - - I know exactly where 3 of them are - - when I feather on the brakes the shimmy dies out, or I just stay around 35 mph or below on small streets.

 

[butch27]

I,m running 6 degrees of caster and so far it seems O.K. Had it up to 70 mph