New To Jeeps.. Got Death Wobble, Have Questions (Parts, Lift, Etc)

[mccula]

Hi everyone, let me introduce myself. My name is Jon, I am the proud owner of an 88 Manche. She's a 4.0l with a poopgo 5 speed trans. Currently, I have it lifted 3.5" in the front with v8 zj springs and homemade lift spacers. In the back I have a pair of chevvy drop shackles, and I'm waiting to possibly do an s10 bastard pack (have the s10 leaves and all the parts, just haven't gotten to it.)

 

I'm new to jeeps, but I've worked on cars for quite awhile, including VW's and muscle cars (70 dart 340 4 spd, and a 69 cuda also 340 4 spd.). When I got the manche, everything was pretty good except a slight vibe at around 55-70mph (not death wobble) and hard shudders when braking at highway speeds. I changed the front rotors and pads and that took care of the vibes from braking. When I put in the zj springs and lift spacers, I test drove it a few times. Everything felt alright until I got on the highway. At highway speeds I now get death wobble. I don't know what sets it off, I'll be driving and then all the sudden it will shake VIOLENTLY for 30-40 seconds and then stop.

I'd really rather not go through and just haphazardly replace front end parts without knowing what the problem is...

Right now, everything is stock besides the parts listed above. The front axle did shift towards the drivers side, I guess because I am on the factory track bar. I haven't gotten it aligned yet because I'm scared I'll take it to a shop that will put it at factory (not lifted) specs or not do the alignment right.

 

Looking under the front, there are no areas of visible shiny metal that would indicate anything moving or anything like that. The lower control arm bushings look a little beat, I know my tranny mount is pretty beat, not too sure about the track bar/bushings or any of the other front end bushings. When you grab the tie rod and twist it, it does twist and kinda 'clunk.' When steering while moving slow, you can hear some clunks, too (it always did that since I bought it stock though). Not too sure about the TRE's or the UCA's or their bushings.

 

Anyway, I don't want to replace any parts with stock because I am seriously considering a higher lift (probably 5-6"). So, any ideas on what to check for right now until I get a lift? If I do need to replace parts, what company offers the most complete lift set up? Or would it be better to piece a kit together? I was looking at rough country's kits, and also rocky road outfitters too.

I have already bought tj front soft lines, and the rear line has been extended because when doing the shackles, I broke one of the hardlines, so I just extended the hard line about 2-3" in the rear. I know I'd need new shocks, springs, probably adjustable LCAs, probably a track bar, extended swaybar discos, hardware for a rear SOA... anything else?

Should I look into getting some sort of front-end rebuild kit (like all bushings, etc) from somewhere like summit or something like that?

 

EDIT: I know people will say to re-gear/swap front and rear diffs/trans eventually. I'm not worried about all that yet... maybe later, but not now. This jeep is my daily, and until that changes I don't want to build it TOO heavily. I'm fine with going a little slower because of the crappy gear ratio and all. I think she's on 31's right now and I have no problem running 31's or 32's.

 

Thanks in advance. Appreciate your time.

-Jon

[mccula]

PS- sorry for writing a novel as my first post! Haha.

[mountainman]

Get an adjustable track bar and then get it aligned. :)

I have found so far that death wobble seems to be directly tied to the tires friction on the road. So when you hit a bump that connection is broken and then when it tries to reconnect with the road it can't and starts bouncing. My truck did it when it was all stock, in a rare occurence on a corner. I checked the toe and it was off. reset and no issues again. ( i drive thousands of miles at a time). Was on camping road trip that time.

Then i lifted it 2 inches... bam it was back bigtime. 3 times in one day. Checked toe.. it was all jacked up again. I also had to move my track bar over an inch due to it being slightly bent from an accident. So now my front end is dialed and I'm running 31"s and havent had any wobble at all.

Of course balance can also play into this. Get all 4 balanced and rotate if tread dictates the need to.

 

Oh yeah... all the stuff in my front end is 186k miles old. So its not that anything is worn out, cause my control arm bushings look like a dry lake bed....lol... yet i was able to cure the problem. Also of course if track bar is loose, it won't keep everything where it should be and then multiplies the death wobble problem once it starts.

 

 

Youll get it. :)

[Pete M]

welcome to the club!

 

personally, I'd pull that spacer until I was ready to lift it to it's final height. without longer control arms and a longer track bar, you'll never get a good alignment at 3.5". and the parts you'll need at 3.5" are most likely not what you need at 5"+, so you'll be saving money by doing it right just once. :thumbsup:

[mountainman]

This thread helped me a ton.

 

http://comancheclub....e-yall-running/

 

Ive been doing mucho research because of that thread.

 

I'm doing the ruffstuff SOA kit for the rear and putting my d44 in at same time.

 

Doing either rock krawler or clayton 4.5" springs up front, because i have 2 inch steel pipe spacers now.

 

Then I'm debating between many diff control arm and track bar options up front.

 

And when done ill be on 33" KM2's

[mccula]

Get an adjustable track bar and then get it aligned. :)

I have found so far that death wobble seems to be directly tied to the tires friction on the road. So when you hit a bump that connection is broken and then when it tries to reconnect with the road it can't and starts bouncing. My truck did it when it was all stock, in a rare occurence on a corner. I checked the toe and it was off. reset and no issues again. ( i drive thousands of miles at a time). Was on camping road trip that time.

Then i lifted it 2 inches... bam it was back bigtime. 3 times in one day. Checked toe.. it was all jacked up again. I also had to move my track bar over an inch due to it being slightly bent from an accident. So now my front end is dialed and I'm running 31"s and havent had any wobble at all.

Of course balance can also play into this. Get all 4 balanced and rotate if tread dictates the need to.

 

Oh yeah... all the stuff in my front end is 186k miles old. So its not that anything is worn out, cause my control arm bushings look like a dry lake bed....lol... yet i was able to cure the problem. Also of course if track bar is loose, it won't keep everything where it should be and then multiplies the death wobble problem once it starts.

 

 

Youll get it. :)

Thanks for the help mountainman. Is there any way I can get away without an adj. trackbar for right now? I know I can relocate it... just have to redrill it to the right AFAIK. How should I go about checking over the front end? Jack it up, put it on stands? Wheels off? What should I look for/do? Can I do a basic alignment myself first before I get it in to a shop? How should I go about that?

Thanks so much. Sorry to ask so many questions.. but you gotta learn somewhere right?

[mountainman]

Thats what i did. While its a bit hokey, its plenty strong to drive the truck till i get all the proper stuff i want. I'm getting a different axle up front anyways. So i drilled my track bar bracket over about an inch. put my axle dead center.

As for alignment just use the tape measure trick up front to set the toe. Searching on this site for hours will get you all kinds of info.

Also look at what hornbrod says about setting his caster. he didnt need many shims at all to get the caster back to correct. So you can prob hit the junk yard, get some caster shims from any XJ or Mj and then pop in an 1/8 inch or so.

That will center your wheels in the front fenders and get the caster back closer to stock. Setting those two adjustments should get you by till you go all in. :)

[Eagle]

At highway speeds I now get death wobble. I don't know what sets it off, I'll be driving and then all the sudden it will shake VIOLENTLY for 30-40 seconds and then stop.

 

I have never heard of death wobble that stops by itself without your slowing the vehicle down to a complete (or almost comple) stop.

 

I haven't gotten it aligned yet because I'm scared I'll take it to a shop that will put it at factory (not lifted) specs or not do the alignment right.

 

What's your idea of "lifted" alignment specs? Why do you think the wheels should be pointing any different on a lifted truck than they do on a stock truck? If you didn't have problems before the lift, and you do have problems after the lift, then obviously the lift changed something and you need to get it aligned to find out what.

 

Lifting a Comanche affects the caster (which is critical), and also (to a small extent) the toe-in. Both can contribute to death wobble. So can (and does) tire balance. And if the alignment is marginal, then tires that were balanced "okay" before suddenly aren't. Those "slight vibes" you had before at 55 MPH? That's tire balance. It doesn't seem to matter what tire size, improper balance ALWAYS seems to result in shimmy at between 55 and 60 MPH.

 

Your truck needs to meet the front end man.

[mccula]

I have never heard of death wobble that stops by itself without your slowing the vehicle down to a complete (or almost comple) stop.

 

What's your idea of "lifted" alignment specs? Why do you think the wheels should be pointing any different on a lifted truck than they do on a stock truck?

 

Well I wouldn't know what else to call it... it stops when I slow a little, but I don't need to come to a complete stop. I'm talking 30 seconds or so of VIOLENT shaking.

The tires might be out of balance, although it's helpful to know that I have rotated them actually before lifting it, which didn't stop the slight shimmy... so that would mean all 4 or at least 2/4 would have to be out of balance...

And as far as my idea "lifted specs", I've been doing a lot of reading in the last week or two and seem to come across statements like this a lot: (from http://www.kevinsoff...eathwobble.html) "If you have a lifted vehicle, make sure that the alignment shop you choose knows the variant specifications for lifted vehicles, and that they do NOT set it to the "default/stock" settings. A good quality alignment shop familiar with 4x4 vehicles will know these settings, and a poor quality shop will likely tell you that it doesn't matter whether it's lifted or not...they still use the same specs. Hang up the phone and call the next shop, if so."

[ftpiercecracker1]

And as far as my idea "lifted specs", I've been doing a lot of reading in the last week or two and seem to come across statements like this a lot: (from http://www.kevinsoff...eathwobble.html) "If you have a lifted vehicle, make sure that the alignment shop you choose knows the variant specifications for lifted vehicles, and that they do NOT set it to the "default/stock" settings. A good quality alignment shop familiar with 4x4 vehicles will know these settings, and a poor quality shop will likely tell you that it doesn't matter whether it's lifted or not...they still use the same specs. Hang up the phone and call the next shop, if so."

 

:agree:

[Eagle]

I still don't know what you think "lifted specs" are, and I can't tell you because I have no idea what that means. Alignment specs typically cover three things: Caster angle, camber angle, and toe-in.

 

Toe-in should be as close to zero as possible UNDER DYNAMIC CONDITIONS, which means with all slop in tie rod ends, etc, pressed out the way the wheels would be rolling down the road. We typically set toe-in to about 1/16" to 1/8" with the vehicle at rest to allow for that slop, but a good front end machine will push the tires out to get a more accurate setting. This doesn't change because of lift.

 

Camber is not adjustable on the Comanche, and because a lift doesn't move the axle relative to the road and it's a solid axle, this also doesn't (and can't) change as a result of lift.

 

What DOES change due to lift is caster angle. Our trucks need around 6 degrees to 7 degrees of positive caster. Lifting the truck moves the control arm pivots relative to the axle, thus affecting caster. Too little caster contributes to death wobble. Adjusting it back within spec (preferably as close to 7 degrees as possible) **may** help alleviate death wobble. I don't regard that as "lifted specs," I regard it as adjusting it back into spec after the lift puts it out of spec.

 

As to tire balance -- if you had a wobble at 55 to 60 MPH, your tires were (and still are) out of balance. That's not negotiable -- that's a fact.

[mccula]

Eagle- Thank you for the info!

I was going to take my truck to RPM Offroad in Bristol TN (I live in the tricities TN area) for an alignment but I may end up just taking it to a more local shop as it'll probably be a bit cheaper...

I hope you're right about the tires... after I get the "pseudo-death-wobble" figured out it would be nice if a good balance fixed that 55-70ish issue. I just didn't think that would be it because like I said, I rotated them and didn't notice any change at all. Thanks again!

[Eagle]

I've been driving (legally) since 1960, and I can remember my parents commenting on the shimmy kicking in at 55 MPH on my mother's 1958 station wagon. Intuitively, it would seem that different size tires should start to shimmy at different speeds, but it's always around 55 to 60 and seems to be independent of tire size. (Caveat: the largest tires I've ever owned have been 31x10.50-15s.) Properly balanced tires do NOT shimmy at 55 MPH. If rotating didn't chase it away, it just means that at least two of your tires are out of balance.

[mvusse]

When I lost a wheel weight on my Geo Prizm (RIP), the only thing I felt was a vibration that started right around 70mph. But those were dinky little P175/70R13 tires.

[Eagle]

Toe-in should be as close to zero as possible UNDER DYNAMIC CONDITIONS, which means with all slop in tie rod ends, etc, pressed out the way the wheels would be rolling down the road. We typically set toe-in to about 1/16" to 1/8" with the vehicle at rest to allow for that slop, but a good front end machine will push the tires out to get a more accurate setting. This doesn't change because of lift.

 

Let me clarify/correct this slightly:

 

What does NOT change about toe-in is that we always want the tires to be parallel (straight ahead) when the vehicle is driving stright down the road. The ideal toe-in is always zero, and the spec is always whatever will result in zero toe-in (or toe-out) when driving. The "spec" does not change.

 

However ... due to the geometry of the steering linkage, the actual toe-in DOES change when you lift an MJ. Lift results in more toe-in -- lowering (or removing lift) results in toe-out. A 4" lift changes the toe-in sufficiently to wear out a set of front tires within a few hundred miles.

[HOrnbrod]

A couple of things I've learned over the years regarding accurate tire balancing are to make sure that the shop pulls ALL the weight off each wheel and starts balancing from scratch. Even better pull them off yourself before turning it over to them. And go to a shop that uses a Hunter Road Force balancer. Call around and find a shop that uses this machine before going there. There's no more accurate machine out there today and it's idiot operator proof.

[marie]

While tire balance can be an issue, I had a death wobble and it was from other issues. My Comanche is an 88 4.0 4X4. I did have tire balance checked as my first option. Next I went with the track bar because it had obvious wear. Moved on to the steering damper as it was leaking. Then the center link and what looks like a tie rod end on the center link near the pitman arm. I also replaced the tie rod end that attaches to the middle of the center link at that time too. My friends at Napa were a little stumped at this point too. They even came out jacked it up and looked themselves. The next suggestion was the steering shaft from the firewall to the gear box, still no luck. I decided to go for the tie rod end at the wheel. As I crawled under the truck and was spraying the rusty old nuts with WD, I looked further up into the engine compartment. I noticed a missing bolt and three with the nuts half off. Two of the loose nuts were for the motor mount. The one missing bolt and the third one that was loose, were what held the mount for the track bar to the bottom of the motor mount. Finally resolved! But, before you start thinking "dumb girl thinking she can work on her truck and isn't strong enough to tighten bolts properly....." There is only one part in this whole process that I did not put on myself, and you guessed it, it was the track bar, the part that came loose. I’m not blaming anyone, it just wasn’t me. I have a couple of lengths of pipe that are my equalizers. I am a master of mechanical advantage. :chillin: Anyway, that’s my story on death wobbles. If it doesn’t help you hopefully it will help someone else going through the forums.