Front Wheel Wobble?? HELP (1 Viewer)

[Btchnfj]

Hi all, So I've been have an on going vibration issue and have finally resolved it to a loose tranny mount. Anyways today I drove it to work about 24 miles and once I got off the highway I noticed a wobble coming from what felt like the front end, and could hear it audibly. On the way home from work I noticed it was very specific to hitting a bump on the road. I can feel it in the pedals and shifter but can only lightly feel it in the steering wheel. I jacked it up once home, after driving very easy worried it could be a wheel bearing and couldn't feel really any significant play in the wheel saying its a bearing. Not sure what else it could be. But it makes me think its either a bad wheel bearing or reminds me of what it feels like when a shock is bad, but don't think it could be a bad shock. OH and this is on my 79 FJ40 with a 4inch suspension lift and 33in all-terrains. Thanks for any help. I might end up digging into check the wheel bearings at the very least to give me piece of mind.

 

[65swb45]

Do some research on "death wobble."

 

[78fj40mg]

Hi all, So I've been have an on going vibration issue and have finally resolved it to a loose tranny mount. Anyways today I drove it to work about 24 miles and once I got off the highway I noticed a wobble coming from what felt like the front end, and could hear it audibly. On the way home from work I noticed it was very specific to hitting a bump on the road. I can feel it in the pedals and shifter but can only lightly feel it in the steering wheel. I jacked it up once home, after driving very easy worried it could be a wheel bearing and couldn't feel really any significant play in the wheel saying its a bearing. Not sure what else it could be. But it makes me think its either a bad wheel bearing or reminds me of what it feels like when a shock is bad, but don't think it could be a bad shock. OH and this is on my 79 FJ40 with a 4inch suspension lift and 33in all-terrains. Thanks for any help. I might end up digging into check the wheel bearings at the very least to give me piece of mind.

Here try this: Search Results for Query: death wobble | IH8MUD Forum

 

[Btchnfj]

So far I took down both front wheel hubs and found nothing significantly bad on them, I'm awaiting for the 54mm to reinstall and can only wonder if maybe there is slight play in the wheel bearings from when they were last installed and that's the wobbling sound I'm hearing and feeling. My wobble although is different than some others, it doesn't wobble like a wheel is out of balance and its only felt when the car drives over a bump. Anyways today I was checking all the torques around in the area and found that all the nuts for the upper and lower knuckle bearings were loose. Not sure yet if that is the cause will have to wait until tomorrow when I put all back together to find out.

On another note, what should the wheel bearing be torqued to? I read in the Haynes manual to tighten and than loosen 1/8 turn...and the Chilton's doesn't give anything for it, but does give a torque for the pick-ups, it says 37ftlbs and than back off and torque to to 18ft lbs.

 

[B y r o n]

. . . I noticed it was very specific to hitting a bump on the road. . . .

With a 4" suspension lift it is possible that what you are feeling is bump steer. Can you post pictures of your steering setup from multiple angles to help in the diagnosis?

 

[Fast Eddy]

How are your leaf spring bushings, TREs and rag joint? If they're all a bit old, that can add up.

 

[Btchnfj]

Everything is about 10 years old after the frame off restore. There is only one TRE that needs a new rubber cover but other than that everything is in good shape and well taken care of. My rig has only seen very minor dirt, and is pretty much a pavement princess. So I would say that all the suspension components seem in good order. I also regularly grease them, probably about twice a year. I just greased the entire chassis last week. I'll post picture tomorrow though.

 

[sggoat]

Wheel bearing issue should be able to be resolved by feeling the hub--if it's hot--you may have a prob. Jack up the wheel--see if it wiggles--

 

[Btchnfj]

Wheel bearing issue should be able to be resolved by feeling the hub--if it's hot--you may have a prob. Jack up the wheel--see if it wiggles--

I have done that and have felt nothing, nor have I felt too much heat coming from the wheel hub. I'm about to re-assemble the hub assembly's and see what I get. Will update post when done. Still not sure of the wheel bearing nut torque though

 

[Btchnfj]

With a 4" suspension lift it is possible that what you are feeling is bump steer. Can you post pictures of your steering setup from multiple angles to help in the diagnosis?

Ok so I finished putting the wheel hubs back together and noticed no significant change. Here are the pics of my steering. I'm beginning to think its a TRE issue.

 

[JohnnyC]

You look shimless

 

[B y r o n]

You are running a 4" lift but still have the original steering. That means the angle of the drag link is higher than the factory configuration, this will cause bump steer. To eliminate bump steer with raised rigs a dropped pitman arm is normally used to lessen the angle between the tie rod and drag link. I've never seen a dropped center link arm so don't know how you would correct this except possibly a high steer kit.

If you think there may be other issues with the front suspension read post #9 here.

Here is some additional info on the subject.

 

[jm599]

Last week developed a slow speed wobble after hitting bumps in a 4" lift spring under. Would go away with braking or w speed. Jacked it up and when pulling outwards on the right side tire at 12 o'clock, could feel a clunk. Took it apart today suspecting a wheel bearing to be worn or loose.
Wheel bearing was fine but upper trunion bearing fell apart removing upper steering arm. Parts arrive in morning, hope it fixes mine.

 

[sadam_husain]

what sort of condition are the TREs in it might just be the angle of the photo but the RH one looks a bit worn is there any play in it?

 

[Weber Sarge]

If you haven't rebuilt those knuckles in awhile - death wobble could become a problem . It's all down to preload on the king pin bearings - that gives the steering knuckles a slight drag to prevent them wobbling when you hit a bump . Combined with the felt/rubber seals on the knuckle balls this preload can be missing when the knuckles are worn .

Disconnect the tie rod ends and see how much drag each wheel has when turning with the tire off . I'd bet the passenger side is really loose since it wears the most first on those king pin bearings .

Sarge

 

[Btchnfj]

what sort of condition are the TREs in it might just be the angle of the photo but the RH one looks a bit worn is there any play in it?


View attachment 1273732

Yes, that's where I'm looking at next are those TRE's. The drvier's side is in need of some attention since its boot is cracked. Also when I turn from side to side I can feel the play in it, Although I sum that up to the one side having a bad boot so it won't hold any grease.

Also Weber Sarge, I finished the restore about ten years ago and have only driven it over the weekends. Over the ten years theres maybe 30k on the truck. So I would venture to say that the knuckles are still in good shape. Last night I finished putting the hub assembly's back together with all the correct torques. Also when the truck is lifted with the wheels off the ground I felt no movement on the wheel at all. Although the upper and lower knuckle bearings where out of torque limits by about half a turn on the nut...

My next step will be to try and fix the TRE's and try to help fix the bump steer. Does anybody have any ideas to help fix the bump steer? Maybe switch the TRE's from going up through the bottom to going down from the top...?

 

[tlc762]

Your TRE's have a tapered shaft on the mounting bolt which matches the taper in the knuckle arm hole. The TRE's will not go in "upside down" in the arms because of the tapered holes- if they do then you have other problems...
HTH,
Will

 

[too tall]

I would get a friend to help you and touch each joint at each of the connections . Get your friend to rock the wheel back and forth to feel the free play . If you are touching each side of the connection you will get a better feel/idea where the majority of wear is . Better than just a visual as the rubber boots hide problems sometimes .

 

[lostmarbles]

what sort of condition are the TREs in it might just be the angle of the photo but the RH one looks a bit worn is there any play in it?

We're both kiwis ..... but I'm with Sadam here.

One look at this picture and alarm bells are ringing in my head... No way would I be happy seeing any balljoint on my BJ40 looking like this one does:

Jack that wheel off the ground (while leaving the RH one on the ground) and grip the tyre and try turning the wheel left and right.

I bet that particular balljoint has heaps of play.. In fact it looks to be about to break apart to me (and looks to be a VERY SERIOUS safety risk).

 

[Weber Sarge]

If those nuts were loose , there is a chance a bearing got hammered enough to loosen the preload off - seen that many times . Knock those tie rod ends off and check them closely - and inspect the preload on those knuckles . That's the baseline , then go from there ...
Sarge