jeep guys need advice

[Mitko]

there are lots of different scenarios to consider.

Non doubtful - the list of possible causes is as long as Shindler's list. But you never say B before saying A, right? What I am at is that when diagnosing a problem a man should always start from the most possible cause. Not to mention that checking the track bar is the easiest to diagnose and doesnt even require to lift the vehicle of the ground.

 

[junkpile]

^^^^
Yes this.
Wether or not it fixes the problem always replace the sticking caliper or loose track bar or loose wheel bearing etc..... Best to repair all known obvious faults before attempting to track down something else. If for no other reason than to keep ahead of the maintenance of your rig.

 

[junkpile]

I am curious though, anyone in here running hydro assist in their jeeps suffering from DW?

 

[aweber]

I am curious though, anyone in here running hydro assist in their jeeps suffering from DW?

Hydro Assist solved it on my Solid axle Toy when it was street driven.. Rather it made it go away instead of solving it but same thing

 

[Kunker]

Hydro Assist solved it on my Solid axle Toy when it was street driven.. Rather it made it go away instead of solving it but same thing

And I'm the opposite - no problems until the axle swap and hydro assist. It's awesome watching a 36" TSL swing back and forth 3-4" with your head out the window at 80ish. Leaf sprung CJ, I have a feeling it's at the very least the fubar'ed front leaf mounts.

 

[junkpile]

Sorry, what meant was:
Were your TSL's bias ply?
You were experiencing death wobble at 80!? You're putting a capital D on death wobble! Lol

 

[aweber]

Bias TSL's too? At 80!? You're putting a capital D on death wobble! Lol

I had Bias TSL/SX's and hit 140 in the Toy

 

[Kunker]

Bias TSLs here (no SX), and I don't actually have a speedo in the CJ, so no clue on speed. I would guess 80ish. Smooths out after, just a handful at a certain speed. I also think it may be due to some flat spotting in the tires (at least a bit) as it wasn't happening after having the CJ out for the day, but is ridiculous after it's been sitting for a while.

 

[junkpile]

Yeah sounds like tires to me, those big bias ply can really shake.

 

[2Greys]

Bias TSLs here (no SX), and I don't actually have a speedo in the CJ, so no clue on speed. I would guess 80ish. Smooths out after, just a handful at a certain speed. I also think it may be due to some flat spotting in the tires (at least a bit) as it wasn't happening after having the CJ out for the day, but is ridiculous after it's been sitting for a while.

Usually DW doesn't show up until 45mph (aka 80kph) and it is rare that you can drive out of it.

 

[junkpile]

I'm going to politely disagree with that one. DW in my experience occurs anywhere from 40-60km/h
Caster starts to naturally pull everything tight from 70km/h up. Anything from 80ish up I would contribute to tire balance, shifted belt, out of round etc. Usually(not always) centrifugal force starts to force everything round somewhere over 120km/h, so everything starts to feel smoother.
If you are experiencing DW at higher speeds I'm going to suspect serious caster angle issues causing a "shopping cart" type situation.

 

[Mitko]

Not to be an expert, but in most of the cases I had to deal with DW AKA Shimmy, about 20 different vehicle, including two mine (a TJ and the gray G) the wobble always started at 70-75 km/h. At around 80 all of the vehicles were uncontrollable. The tire balance shake start to show up usually at over 100 km/h. (Sorry but I am absolutely sure about this, doing it for living every day, including today) The broken belts show up at over 50 but do not cause DW.

 

[2Greys]

Both my experiences started at 80kph and I couldn't drive out of it, I got it up to 100 before giving up trying to drive through it and it killed my steering stabilizer doing it. Second time I kept the speed under 80 and only had the one time.

In both cases (trackbar and ball joints) I didn't need to do an alignment after so it definitely was not caster based. Replaced the bad parts and it didn't happen again while before it was easily predictable. DW needs to have slop in the system for it to happen (at least in jeeps anyways). It's a harmonic frequency that the system doesn't like.

If you are going to base it on personal experiences you would be hard pressed to find someone on JF who didn't have it start around 80kph and end up being slop. I think I have seen one person who it ended up being a tire out of balance. Everyone else was TB, TREs, couple CA bushings and a couple hubs.
That said looking at how... consistent Jeep is with their build specifications it doesn't surprise me that there are exceptions.

 

[Mlorint]

Death woble can come from a tight front end. It is normally due to caster being close to 0 degrees. For a tj the spec is 7 degrees. If you have lifted a vehicle the caster will be reduced and cause you to constanty correct. It is very important to have an alignment done after a lift and to make sure they adjusted the caster. If anyone is interested in seeing how to check there front end properly, I can show you how at my shop at home. Pm me and we can set up a time, it will take about 5 minutes to check.

 

[junkpile]

I think we're all on the same page here. The point I was trying to make was that DW at higher speeds 70+ is most likely caused by poor caster angle and only accentuated by whatever loose part(s) you have been neglecting to replace/repair. Replacing the parts will improve the overall feel but only by adjusting the caster will you correct the problem.
At slower speeds (where I have seen more) the problem is less likely to be contributed to caster angle and more likely to be caused by a worn out part. One of those overlooked parts I suggested to be the steering box.
Some lucky people who run bias ply swampers get to experience the violent shake/shimmy/wobble even while driving their tight, maintained, perfectly aligned vehicle, and if they (Aweber I think it was) have the balls to stay in on the skinny pedal to 120+ things tend to smooth out.
I too played the flat rate game for 15yrs, 13 of those for a Dodge Chrysler Jeep dealer, now I'm a stay at home dad/trophy husband.
Cheers!

 

[2Greys]

I think we're all on the same page here. The point I was trying to make was that DW at higher speeds 70+ is most likely caused by poor caster angle and only accentuated by whatever loose part(s) you have been neglecting to replace/repair. Replacing the parts will improve the overall feel but only by adjusting the caster will you correct the problem.
At slower speeds (where I have seen more) the problem is less likely to be contributed to caster angle and more likely to be caused by a worn out part. One of those overlooked parts I suggested to be the steering box.
Some lucky people who run bias ply swampers get to experience the violent shake/shimmy/wobble even while driving their tight, maintained, perfectly aligned vehicle, and if they (Aweber I think it was) have the balls to stay in on the skinny pedal to 120+ things tend to smooth out.
I too played the flat rate game for 15yrs, 13 of those for a Dodge Chrysler Jeep dealer, now I'm a stay at home dad/trophy husband.
Cheers!

Same book but not necessarily the same page. Stock caster setting for a TJ/Cherokee is 7* but when you lift it if you keep it a t 7* you will end up getting vibes as the pinion is no longer pointing properly at the TC. Pinion angle overrides caster and rule of thumb is 4" lift equals 5.5* caster. You would have to majorly screw up on the caster to set it to 0*. It's actually quite easy to set the caster on a Dana 30 using just an angle finder (even easier if you have adjustable control arms). That said after doing a lift it is a good idea to get it professionally done on a machine to get a good baseline and then tweak if needed depending on the place that does it and if they do everything according to stock values.

Also the fact that Chrysler put out a TSB last year about DW on the JKs attributing it to worn steering components and how to repair it is very telling. They did mention that if tires are not balanced or inflated properly it could throw it into DW although I think what they are alluding to there is that it could put more stress on the steering components causing premature failure.

I wasn't disagreeing that the steering box couldn't be the problem just that it isn't always the problem and looking on JF the most common culprit has been the track bar.

 

[junkpile]

2greys- you just quoted my post but I'm not sure you're actually reading my posts before you decide to argue with them. I never specified any specific angle values nor did I state that all is fixed with a steering box. Lastly, the sky is blue.

 

[Loco]

Also the fact that Chrysler put out a TSB last year about DW on the JKs attributing it to worn steering components and how to repair it is very telling. They did mention that if tires are not balanced or inflated properly it could throw it into DW although I think what they are alluding to there is that it could put more stress on the steering components causing premature failure.

I have had DW in my Sami solely caused by both front tires being slightly unbalanced and coming into phase with each other. Completely cured by rebalancing the tires. Not the same vehicle, I know, but still similar dynamics.