Frame Cracks Causing death wobble?

alright, I've had death wobble for far too long and nothing has fixed it. Tried every text book solution I could think of to no avail. Today I'm under there and notice that there are cracks on the bottom of the rail under the steering box. It looks like it might start under the sway bar mount and continue about 4-5 in back before it turns to go up vertically on the out side of the rail. the crack stops just before it actually turns the vertical but it probably wont take long before it does. I can't believe I've never seen them before as they're quite substantial. With someone steering back and forth you can watch the main crack separate and then compress, it separates between 1/16-1/8 in:shocked:

Will cracks cause death wobble or is this a product of the relentless shaking that I've been forcing upon my poor jeep? The jeep has been HAMMERED for at least 6-7 years and then driven with the death wobble for about 5 months so Its not surprising to see these cracks. But with nothing else curing the wobble I wonder if the cracks are the problem or merely a product? I know cracks are common but after searching I have not found anyone saying it will cause the dreaded wobble.

If they allow for play in the steering or trac bar then they can give you death wobble.

-Alex

Heres something to think about.

I talked to Terry at rigidco, and he said there was a specific reason why they started making the bumper with thebulkheads up front.

His son's jeep had a bad case of dw, and the problem was traced back to the corners on the front frame rails, where the welds join the bulkhead to the rails.

His system apparently tightened it up, and fixed the DW.

my bumper is stock and by no means solidly mounted to the body It prob. has two bolts total holding it on. What bulk heads are you talking about? Is it the front cross member that ties the two "rails" together side to side?

My plan of action is to tear most the front drivers side down to the bare unibody (as much as possible at least) Clean all cracks, drill the ends and weld them to the point that they don't move while turning the wheels in the drive way. Then take it for a drive and see if there's any DW or notice-able improvement. If this doesn't help then thats it for this little Heep!!! anyone want and 89 XJ with eternal DW?

If they allow for play in the steering or trac bar then they can give you death wobble.

Click to expand...

My guess is that the cracks were CAUSED by death wobble, not the opposite. That would have to be a huge amount of slop to actually make your rid start shuddering.

DanMan2k06 said:

My guess is that the cracks were CAUSED by death wobble, not the opposite. That would have to be a huge amount of slop to actually make your rid start shuddering.

Click to expand...

It doesn't take much slop to cause DW. Those cracks need fixed asap, before the steering box rips off the frame and you have no steering.

DanMan2k06 said:

My guess is that the cracks were CAUSED by death wobble, not the opposite. That would have to be a huge amount of slop to actually make your rid start shuddering.

Click to expand...

when I first noticed the cracks and saw how much they moved I though I had found the cause of the dw. but after thinking albout it all day I'm not too sure, It's been over a year since I stopped driving this beast and prob 2 years since the dw started. I've spent countless hours under there checkin things out and had never noticed them until now which makes me think that they were prob caused by the dw and not the cause. It also bugs me that there is a lack of rust and corrosion.

either way, I tore everything down and welded the cracks tonight, it was too late for me to want to take it for a drive so that will have to wait till tomorrow. if I see any improvement then I'll prob fab up some sort of support/reinforcement tomorrow

my next question is to what extent do I need to reinforce that section? I know some people go all out and do most of the rails front to back but I'm mostly just worried about the area of the steering box and track bar. I was thinking I could fab a plate to go from just behind the bumper mount back to the track bar mount, and then one on the underside about the same lenght. I took off the steering box and saw no evidence of cracking on the inside so I'm thinking I can leave that part alone. Any thoughts?

Get yourself a c-rock brace or something similar.

The steering box flexes against the unibody, particularly with bigger tires fighting it. The bolts start to oval out their sleeves, the sleeves break, and then it starts working on cracking the frame.

Just went through it with mine. Put a c-rock plate on, its never steered tighter.

ihblarp said:

my bumper is stock and by no means solidly mounted to the body It prob. has two bolts total holding it on. What bulk heads are you talking about? Is it the front cross member that ties the two "rails" together side to side?

My plan of action is to tear most the front drivers side down to the bare unibody (as much as possible at least) Clean all cracks, drill the ends and weld them to the point that they don't move while turning the wheels in the drive way. Then take it for a drive and see if there's any DW or notice-able improvement. If this doesn't help then thats it for this little Heep!!! anyone want and 89 XJ with eternal DW?

Click to expand...

http://www.flickr.com/photos/rigid/sets/72157601335658760/

Rigid uses a separate add on bulkhead to remove the slop and add reinforcement.

so does the c-rock have sleeves that replace the stock ones or is it just two plates that sandwich the rail. I don't really want to buy anything that I could just make myself, im just not sure of what works best as far as bracing.

the cracks started small and got bigger. they are the cause and the result of death wobble.

had it happen to me. got bad enough that I just started running over stuff with the jeep cause it was a shitbox anyways. ran into/over stuff in the back woods for a few months until I finally flipped it and killed it. then stripped what was good and scrapped it.

had another cracked frame rail on my 86 comanche tho, and I stop-drilled the crackes, welded them, and made a frame plate with fish eyes instead of vertical then welded it in.