52's, death wobble and tire balance... HELP?

[MTMike]

I suppose I'll start close to the beginning.

Weekend before last MNorby, Joe and I swapped in my DRW D60/D70 combo that had been sitting in a field for God only knows how long. We put all new wheel bearings in and junk yard hub locks, and then rolled it onto the trailer and then towed it to the trail without test running it.

Needless to say, death wobble reared it's ugly head.... my poor wife nearly shat herself the first time it happened.

When we put the 60 in, the u-bolts were too short, so I pulled the overload spring from the 52's. Now the front end of the truck sags slightly and the springs are nearly in reverse arch at static ride height. Could this be a contributor to death wobble?

I also heard (from searching and from guys on the trail) that tires out of balance can contribute to death wobble. Will doing air-soft pelets/bb balancing be enough to preven t any DW from this source, or should I take it in to a tireshop and have them do it?

I plan on shimming the king pins, but I want to address all possible sources of DW.... my plans are:
-KP Shims
-Hydro Ram (which will help my no steering power problem)
-Tire Balancing (which method based on what you guys say)
-Possibly adding a leaf to my 52's

Is there any other area I should address? All steering components are less than a year old. My Pitman arm, and draglink are ~8 month old WFO peices, the steering arm is brand new WFO, the tie rod and TRE's are brand new.

Thanks for reading my long post and thanks for all the help

Mike

 

[6.2Blazer]

Chances are the kingpin is the main cause of the DW. It probably wouldn't be a bad idea to at least pull the knuckle off and inspect the condition of the lower bearing and the upper bushing/spring assembly. The upper springs just were not designed to the large tires and heavy wheels. Probably wouldn't be a bad idea to get the upper rebuild kit (new bushings and springs) which is pretty cheap. On my '77 D60 it had horrible DW when I first installed it and required two washers on each side to shim the spring which stopped the DW. After I installed new bushings and springs I could get away with only one washer per side with no sign of DW. I've never ran a steering stabilizer and have 38" Swampers on steel rims that are partially balanced.

The soft springs and lack of stabilizer can make DW feel worse, but typically they are not the true cause. My guess would be that the kingpin shims will correct the problem.

 

[cegusman]

How do the king pins and bushings look? might be time for an overhaul. Tie rod, draglink, allingment could all cause it too.

 

[MTMike]

How do the king pins and bushings look? might be time for an overhaul. Tie rod, draglink, allingment could all cause it too.

Surprisingly, the kingpin bushings looked really good when I had them apart.

 

[cegusman]

How about the king pin's any pits or rust or anything,

 

[rcurrier44]

Who recentered those double beadlocks for you? I was thinking you might try to put those on the ballancer first and see how true they were. Then take the best two and run them on the front.

EDIT: Oh thats right you didn't have to since you used the duley axles...

 

[MTMike]

How about the king pin's any pits or rust or anything,

Nope, everything looked good to the eye - lots of good grease still in there.

Who recentered those double beadlocks for you? I was thinking you might try to put those on the ballancer first and see how true they were. Then take the best two and run them on the front.

EDIT: Oh thats right you didn't have to since you used the duley axles...

I was going to have them recentered until I found the DRW axles..... They're still heavy pigs that really should be balanced though. I guess my question is: Should I use bb's or air-soft pelets or go to a tire shop and have them done on a machine?

 

[Leper]

What speed is it happening. Mine only shows up at about 35, or if I hit a bump a little slower. I run unbalanced 40s and no stabilizer.

 

[MTMike]

What speed is it happening. Mine only shows up at about 35, or if I hit a bump a little slower. I run unbalanced 40s and no stabilizer.

Between 25 and 40mph (at least according to my speedo ) with practically any bump in the road. Above 40 it only shimmys slightly but never goes into DW, below 25 it's as smooth as silk.

 

[79k20350]

just replace the kingpin bushings and springs and the lower bearings. its not hard to do, should only take a few hours. should cost you under a 100 bucks too. my parts didnt look bad..until i compared them with the new ones. its so cheap to do it should be done. this is where i would start at least.