Tire Bounce...

[badgerd]

I've been running through all of the mechanical stuff on my 87 M998 and am down to one last annoyance, drivers front tire bounces between 56-59mph and I absolutely cannot find it. Below is what I've done so far (not throwing parts at it but fixing neglect):

• Spindle Nut - Bought the 6K "Refresh" kit right after I bought it and replaced the nuts with the double tab version included in the kit. Followed TM procedure for torque, turn, break torque, retorque.
• Shocks - Got a great deal on a set of shocks and replaced because the rears were leaking, so all 4 have new shocks, no change to bounce.
• "New" tires - Fresher set of MT-R tires with run flat installed. Regardless of position, front left still bounces. All have centramatics on them, also, position of the centramatics doesn't change the bounce.
• Ball Joints - Upgraded to the "newer" style MOOG (replaced ones that would no longer take grease). I've only done the front so far, but no change to bounce after install.
• Tie Rod Ends, Idler, Pitman - Again, changed because of neglect, would no longer take grease and seemed to "drift" in the lane. After completing the alignment in the TM, still no change to the bouncing but is much nicer to drive.

I haven't replaced the boots on that half shaft yet, but beyond that I'm really at a loss. It's a 6.2 3SP that's had only the seatbelt MWO completed, so it's VERY much original. What am I missing?

Thanks everyone! Pic just because... I'll eventually get to paint, just have to finish the last of the mechanicals!

 

[frank8003]

So replace the drivers side front wheel and tire.

 

[badgerd]

So replace the drivers side front wheel and tire.

Did that, made no change. Doesn't matter what wheel and tire are on there.

 

[frank8003]

Did that, made no change. Doesn't matter what wheel and tire are on there.

that means it is up in the suspension of the truck somewhere.

 

[frank8003]

see nice diagrams figure 142,143,144,145 in
TM 9-2320-280-24P-1
Something in there has failed/weak/failing.
Is there a big spring in those suspensions?
All springs get old out of specs.

 

[badgerd]

see nice diagrams figure 142,143,144,145 in
TM 9-2320-280-24P-1
Something in there has failed
Is there a big spring in those suspensions?

VERY familiar with the 24P-1, only place to get parts info. Hoping someone had an idea of what, I'm not interested in throwing parts at a problem...

Springs are Figure 192 same manual...

 

[Milcommoguy]

Sounds like your all over it. Problem does't follow tire makes one think something is up with a strong magnetic force field condition or has the virus . (Info not in the TM)

Any chance ??? the previous owner, GI went looking for a land mine or ran it into curb? Bent the spindle ? Does wheel turn true? Bearing race cracked. Broken weld on control arms under paint. Crack broken anything (that was an easy one lol) mounting cups, frame, bushings, etc. I am sure you would have caught that.

The half-shaft thing ?? thinking here ?? might be out of true to hub, introducing some harmonic condition??

Might have to jack it up, spin tire slow with dial indication or a stick (not in TM) and see how it rolls out. (against tire?? or hub spindle better) keep eye on half-shaft TOO.

I am running out of guesses. Pull the centramatic and see how it goes. Maybe something going on there. Rusty ball bearings.

Going down the road... stick head out window and what ya U see. Won't fix it But..............feel the cool breeze.

Sitting on my mechanics stool, staring at it with you, CAMO

Movie time >

 

[badgerd]

Sounds like your all over it. Problem does't follow tire makes one think something is up with a strong magnetic force field condition or has the virus . (Info not in the TM)

Any chance ??? the previous owner, GI went looking for a land mine or ran it into curb? Bent the spindle ? Does wheel turn true? Bearing race cracked. Broken weld on control arms under paint. Crack broken anything (that was an easy one lol) mounting cups, frame, bushings, etc. I am sure you would have caught that.

The half-shaft thing ?? thinking here ?? might be out of true to hub, introducing some harmonic condition??

Might have to jack it up, spin tire slow with dial indication or a stick (not in TM) and see how it rolls out. (against tire?? or hub better) keep eye on half-shaft TOO.

I am running out of guesses. Pull the centramatic and see how it goes. Maybe something going on there. Rusty ball bearings.

Going down the road... stick head out window and what ya U see. Won't fix it But..............feel the cool breeze.

Sitting on my mechanics stool, staring at it with you, CAMO

I'm glad I'm not totally losing my mind thinking there was something easy I was missing. All of the parts replaced were worn and ready for replacement, so I wasn't throwing parts at it, but beyond this I might be! I have a dial indiacator and will check the runout of the wheel on the hub and see how that looks then check the hub itself. When I did the spindle nut I checked the spindle for damage, but anything is possible with a 23 year old rig with only one year of history on it (previous owner inclueded some parts and replaced the IP, but thats all I know).

When I find my clamp pliers again I'll do the boots on the CV and inspect while it's out. I have checked the control arms for cracks/damage as well as the spring.

My last ditch will be to velcro a gopro somewhere to see what's actually happening... It only happens at speed so it'd be hilarious to stick my head under the truck going down the highway!

 

[Retiredwarhorses]

Lose the centramix. I’ve found them to be useless, and even cause issues, just my experience.
have you taken the truck in for an alignment check?

 

[badgerd]

Lose the centramix. I’ve found them to be useless, and even cause issues, just my experience.
have you taken the truck in for an alignment check?

I haven't found a local shop that will do alignment yet, but did do the alignment (string and TM method) myself. Not as good but most places dont' want to touch a "H1" around me either...

 

[Milcommoguy]

IMDS In My Driveway Shop......... DIY is a money maker for tire wear and MPG. Have Band-aids handy.

Something to consider first is to work out the caster and camber based on ones loading needs first. This is in the TM too and will require a bit of work. Simple nuts and bolts to pull the shims, Time and focus to do and save a bundle of $$, Fixs the wear and tear on tires and it just looks right. IMO one of the first things to do to "civilian - ize" the HumV.

Second. As long as you have all the linkage balanced and any play minimized with good hardware, as in gear box, steering wheel centered, drag link, pitman, tie rods adjusted to square the mechanics of steering in the forward direction ... hope that makes sense, all the greasy / joints good...

The string "toe set" with the TM works great. Requires just a little insight to what your looking to achieve. Flat driveway, creeper, maybe a helper to work the dumb end of the tape.

My note: Keep the steering wheel spoke straight down. Balance the adjustments between the left and right tie rods to meet the numbers. while heading straight. Same amount of threads +/- showing all around. Keep the clamp ends hardware away from rim edge.

Very important... repeat for the rear. Keep in mind there's the thrust line. Look that up in your Funk and Wagnall. Don't want the rear going in the wrong direction. Numbers mean nothing if crabbing.

Don't know what the rest of the boy's are doing here, But it was the BEST time spent and Money saved to tame the beast. I'am the guy that has little trust to send it out, come back in a couple of hours and all is good. Truth is, CAN'T be done in a couple of hours and for $99.99 and what have you learned???

More comic book fun with SGT Half-Mast McCanick > https://www.logsa.army.mil/psmag/archives/PS2003/607/607-02-09.pdf

Specs may need a little tweaking for "civilian - izing" the HumV. I miss Connie Rodd.... LOL

BAGGERD.....Back to the wobble - bobble hows the torsion bar connections? Bent, worn bushings? Transferring energy across the front? BIG guess.

Not a hands off HumV guy, CAMO

 

[Mogman]

Sounds like it could be a shimmy not a bounce, it will feel like the left front because you are closer to it than the right front wheel, a go-pro at this point will tell you allot.

 

[DREDnot]

Slightly bent hub is my guess.
Raise it safely on jackstands with all four wheels off the ground and idle it in drive and watch to see if the hub, wheel , and tire run true.

 

[badgerd]

Slightly bent hub is my guess.
Raise it safely on jackstands with all four wheels off the ground and idle it in drive and watch to see if the hub, wheel , and tire run true.

If I could safely do that I’d be in business! Still have a couple other things to check, but this is on the list for sure.


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[Retiredwarhorses]

I haven't found a local shop that will do alignment yet, but did do the alignment (string and TM method) myself. Not as good but most places dont' want to touch a "H1" around me either...

any type of bounce is tire Balancing , a shimmy Is usually a worn pitma, idler, ball joint or rod end.
the M1123’s coming out “about 65% of them I get into the shop” have out of round tired due to sitting for 11hrs in the desert.

 

[DREDnot]

Do you have a GoPro camera? You could mount one under there in a few different spots and see what's really happening at speed.

 

[TOBASH]

Have you tried allignment?

also...

I love centrimatics BUT did you swap the two front centrimantics to see if maybe one is bad?

 

[badgerd]

Have you tried allignment?

also...

I love centrimatics BUT did you swap the two front centrimantics to see if maybe one is bad?

I took the centeamatics off entirely and the only change is the bouncing starts at 55...

I’m still looking for a shop that’s willing to do an alignment even though I’ve already done the string and TM methods. I’m going to borrow a camera this weekend to try to see what’s happening.

Very frustrating...


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[Mogman]

Have you tried to get the tires balanced? I had a couple that were around 24oz out, more than the dynamic balancers could handle.

 

[Daves86]

Have you tried calling High Dust 4X4 in Norflok or 4Wheel Parts in Va Beach? Those are local off road shops, Hi Dust had a great rep 20 years ago before I moved north.