tire wobble

[kevsmith235]

i have a 1979 k5 blazer with a 9 inch total lift.I put a set of 39.5 in super swamper tires.The axles front and back are stock 10 bolt rears.While driving when i hit a bump the whole front end rocks back and forth like i'm losing a tire.it doesn't happen while on a smooth road as soon as i hit a bump its all over.somebody told me to reinforce my steering box this would help.i don't know what to do.

[Joey D]

It sounds like the tires are wobbleing. 1st give the whole steering a good check to see if anything is worn out.
Check the frame area where the steering box bolts to as it may be cracked, even if it's not get the weld in kit to fix it as it will break at some point. They also make a bolt in brace but it should be used with the weld in support to be secure.
Offroaddesign.com sells a nice set up. Get a dual stabilizer for it as this will help

[wyldman]

Like mentioned above,check the entire front end first,as well as the frame area around the steering box.Repair as needed.

It sounds like you have the famous "death wobble",or otherwise known as caster shimmy.On lifted trucks,you need to bring the pinion way up to get acceptable driveline angles.This rotates the steering knuckles forward,and reduces the caster.Caster is what keep the wheels pointed forward,and helps keep them there.It sounds like you need to get it aligned and put some more caster back in it.You may need to re-shim the front diff,and\or add offset ball joints.You will have to find a good balance between acceptable caster settings,and front driveline angles.

Tire balance,or even a bad tire can set it off as well.Check those as well,but i'm sure you'll solve your problem with adding some caster.

[79D604SPD]

Another suggestion is bump-steer. This is caused by the increased distance between the steering arm on your LH knuckle and the pitman arm on your steering box. Normally the adjustable drag link that conncects the two of them is somewhat parallel to the frame. When you lifted the truck the drag link compensated by moving to an extreme angle. The suspension moves when you hit a bump, and the drag link is more sensitive to suspension travel now and allows for large amounts of front end play. I am guessing you have a 6" susp. lift and a 3" body lift? Most lift manufacturers recommend a raised steering arm, new lowered pitman arm, or new drag link. You can also do a combination of these. You didn't mention whether you had installed these or not. The best set-up is something called cross-over steering, but thats a lot more explaining and a lot of modifying.

Maybe check for worn or broken parts first, and I'm sure the alignment is off now, then take a look at that drag link. hope this helps

[wyldman]

The Blazer uses a different steering linkage setup,that isn't real affected as much when lifted.They use a steering arm and a short drag link which still must be raised,but the tie rod connecting the front wheels isn't really affected.Bump steer really isn't an issue on those trucks.

A worn or missing steering stabilizer will make the problem worse,so you could add\replace it,but your problem is still probably related to caster.

[ratlover]

You can get the famos death wobble even from a non lifted truck. Stabalizer is probably shot. Rotating the pinion up and screwing with your caster will make things worse as will bigger meats. Check for cracks around the steering box though since there is a chance its shot like was mentioned. And to quote a wheeler budy of mine "39.5's on 10 bolts makes baby Jesus cry"

[kevsmith235]

thanks for the info guys.Yes i have a 6in superlift suspension lift with a 3 in. body lift.I also have the double rancho steering stabilizer.I looked at the steering box and someone has already welded a crack behind it.I'm going to get the frame kit to reinforce the frame

[79D604SPD]

Wyldman is right about my post, after doing some reading, I realized I got mixed up about steering correction. The primary reason for a dropped pitman arm/raised steering arm(or cross-over steering) is to correct for steering control loss or loss of steering wheel travel when the axle droops and drops the drag link also. not really to correct for bump steer.

[kevsmith235]

where can i find offset ball joints?thanks

[wyldman]

Try Ingalls engineering.

www.ingallseng.com

[thesnoman]

Originally posted by kevsmith235
where can i find offset ball joints?thanks

I think I would look into having the axle tubes removed and re-indexed in the diff housing for a permanant fix with no loss of strenght or reliability and continued use of stock type parts.

[jlsanborn]

I also have what I guess is being refered to as the "death wobble". Sounds spot on (scares the snot out of my wife). My front end is in the stock configuration. I have done the king pins and wheel bearings. Shocks and stabilizer are decent condition. I have been suspecting the super mushy leaf spring bushings.
The wobble usually starts under braking on a bumpy surface and just sort of oscillates from there until I nearly stop.
D60 by the way

[thesnoman]

Originally posted by jlsanborn
I also have what I guess is being refered to as the "death wobble". Sounds spot on (scares the snot out of my wife). My front end is in the stock configuration. I have done the king pins and wheel bearings. Shocks and stabilizer are decent condition. I have been suspecting the super mushy leaf spring bushings.
The wobble usually starts under braking on a bumpy surface and just sort of oscillates from there until I nearly stop.
D60 by the way

It is doubtfull that spring bushings are the cause. It is a a combinaton of Caster and toe in (and some times wrong camber too) that can cause a stright front axle to oscillate. You need to go to a alignment shop that works with that kind of front end a see how much it is out of spec and in what areas as this is a dangerous condition to have.

[wyldman]

Because they don't use any sort of track bar on that truck,the front end is located entirely by the leaf springs.Bad springs,or shackle bushings will cause it to shake as well.Pay close attention to the frame bushings on top of the front shackles.

Warped rotors,or bad tires can set it off too.Any play in the front end\suspension just amplifies it.

Make sure that nothing else is loose in the front end,and have it aligned afterwards.

[chris krebs]

How do you adjust the caster and camber in a straight dana 44 or 60?

[wyldman]

Dana 44\10 bolt - Overall caster can be changed by shimming the axle at the spring pads.This also effects pinion angle as well.You can also set individual\cross caster with offset ball joints.Camber is set with plastic shims between the knuckle and spindle.You can also use an offset ball joint,but it's more work.

Kingpin Dana 60's - Same as above for caster.Camber is set using offset kingpins.

Balljoint Dana 60's - You can set both caster and camber with bushings that secure the upper ball joint.You can get both fixed (indexed with a tab),or adjustable one (that you turn).

[ratlover]

take a spin over to coloradok5.com They know thier K 5's Just dont go running if they tell you that 9" and 39.5's and 10 bolts isnt the way to go. Good group of guys but more into wheeling and into the less lift is more train of thought with lotsa flex.

What case do you have? Shiming the axel may possibly be my choice for the imediat problem. 9" is alot of spring........

[thesnoman]

Originally posted by wyldman
Because they don't use any sort of track bar on that truck,the front end is located entirely by the leaf springs.Bad springs,or shackle bushings will cause it to shake as well.Pay close attention to the frame bushings on top of the front shackles.

Warped rotors,or bad tires can set it off too.Any play in the front end\suspension just amplifies it.

Make sure that nothing else is loose in the front end,and have it aligned afterwards.

If this little sets off your front end, you have other problems. The axle oscillates because it is unstable in caster/camber/toe configuration, not because of bad bushings or springs. Bushings and springs may indeed agravate a front end that is unstable to begin with but on a stable one they WILL HAVE NO EFFECT. The oscillation is primarly caused by toe trying to "pull" wheel in or out and the caster angle is near 0 degrees or slightly negative which causes opposite equal caster changes (when reference to 0 degrees) on each side which tend to cancel each other out and NOT dampen wheel oscillation. Front axles are frequently set with positives caster (angle of pivot pins tipped backwards) to enhance stabilty and sterring wheel feedback and return to center. WHen you get to 0 degrees or negative with a straight axle, it may not take much for it to oscillate. Again curing it with bushing or springs is a bandaid on the real problem, a unstable front axle to begin with.

[wyldman]

thesnoman - I think you should spend some time reading about the death wobble.It's quite well documented all over the web.Lots of good info,as to why it happens.

Toe has near zero effect on a caster shimmy.If you had caster near 0 or slightly negative,it wouldn't just set it off,it would be almost undriveable.You would hardly make it over 10 miles an hour.

All it takes is a little bit of play somewhere for the shake to rear it's ugly head.Springs,shocks,bushings,track bars,tie rods,etc.Any little play anywhere will aggravate it.

You can only have so much caster in a SFA,as you run into pinion angle problems,and other handling problems.

Instead of running off with all this technical jibberish,which most people don't seem to understand (and it's incorrect),lets try getting together and actually helping these people out and solving their problems.You seem knowledgeable enough,so how about it ? Quit the bickering,and trying to correct people (you must make sure your right to officially correct people),and just post your opinion like everyone else,and leave it at that.