Mystery thunk is back...

[Hayes]

Never left, actually. I thought I had nailed the mysterious thunk somewhere under/in front of the driver's side floor, but after securing the mud skirt, I still get the floppy thunk under my left foot when driving over potholes and rough roads.

Already ruled-out:

Body mount.
Control arm.
Sway bar.
Shock mount.

Anyone? Can we pick up where we left off last time, Dan?

Thanks.

Hayes

 

[Texus]

Shock...

That would be my first guess... I'm getting the same with the passenger side @ the moment... the sway bar bushings all look good, as do the control arm's ....

 

[Hayes]

Unless there is a technique I don't know about (very likely), I can't get my shock nuts any tighter.

 

[MoJ]

How 'bout the shock itself?

 

[Hayes]

How 'bout the shock itself?

Could you elaborate?

 

[Cruisin'Carolina]

It could be something wrong internally with the shock....(butting out now)

 

[Mickldo]

Unless there is a technique I don't know about (very likely), I can't get my shock nuts any tighter.

The shocks have a shoulder on the pin that stops you tighening any further. If the nut is tight and the shock has any movement the shock bushes are shot. The shock will flex sideways and the pin will hit the mount causing the noise. Simply replace the bushes (they are only cheap).

 

[Hayes]

The shocks have a shoulder on the pin that stops you tighening any further. If the nut is tight and the shock has any movement the shock bushes are shot. The shock will flex sideways and the pin will hit the mount causing the noise. Simply replace the bushes (they are only cheap).

When you say "has any movement," do you mean up and down? What's a quick way for me to diagnose the shocks? The shocks (OME) are less than a year old, with only a little, very moderatate wheeling. I can't imagine that the bushings (poly OME installed with shocks) are shot, but I won't rule anything out until I'm certain.

Thanks.

Hayes

 

[Mickldo]

Generally if you can grab hold of the body of the shock and rotate it by hand there is enough movement to cause a noise.

Over here in OZ it is SOP to carry spare shock bushes on outback trips as shock failure would probably be the greatest cause of breakdowns after tyre failure in the bush. The shock bushes really cop a flogging on the corrugations common on outback roads.

 

[Hayes]

I've been able to rotate the shock body since the day I installed them.
Does this mean that I didn't get them tight enough?
If so, how do I get them tighter?
I've tried all combinations of vise grips + wrench and I can't get the top nut any tighter.

 

[sjcruiser]

If you could rotate the front shock body, then it's probably the bottom nut the culprit. The top nut only keeps the rock shield from turning.

 

[Mickldo]

If you can rotate the shock body or the dust cover by hand the bushes don't have enough crush on them. Maybe you could shim them up a little with an old shock washer or similar. If you space the bushes somewhere around here....



....the end result will be more crush on the bushes. I would still be replacing the bushes with new ones though if this is your noise.

 

[Riley]

Where does one source the bushes for OME shocks?

 

[Nemo]

I sometimes get a thunk noise coming from that region as well. I have searched and searched and never able to find the culprit. I can spin my shocks as well, and if I grab ahold of it good and move side to side, then I can feel a slight movement. Does that mean the bushings are bad and if so is that normal? They got replaced with the new OME's and I would hope that they last as long as the shock itself? To bad I could'nt give someone a before and after results.

Is there someone on the board here that has recently put in new OME's give us a feedback on what new and tight feels like. IE does it spin or have slight movement?

 

[Nay]

Can you say "eye to eye mount conversion"

Another issue you will face if the shock is loose is over compression. When the shock moves the initial compression is not controlled properly and you end up with substantially more suspension motion.

 

[Hayes]

...a the risk of sounding clueless, how does one tighten the shock mount?

No combination of wrenches and vise grips I've been able to engineer will keep the shock body (I guess it's just the shield) from spinning when I try to tighten the nut.

Hayes

 

[sleeoffroad]

You can add some washers under the top nut to compress the washers more.

Do you have sliders? Check the mount of the DS front to make sure it is not contacting the floorboard.

 

[Hayes]

No sliders.
And in clarification, I cannot turn the lower shock body by hand--just the upper.

Hayes

 

[Mickldo]

I usually use my rattle gun to undo and do up shock nuts but if I can't do that I have a special pair of Vise Grips that have a chain on the end that wraps around the shock body to stop it rotating.

My new OME "L"s don't spin on their bushes. When I installed mine I used rubber grease on the bushes so that friction on the bushes during everyday driving doesn't cause the bushes to overheat. Apparently the friction causes heat and the heat is enough to sort of melt the bushes and cause them to wear away quicker than normal. Even with the grease on them I couldn't rotate the shock body (I had to align the sticker so everybody could see and had to back off the nut to spin it around).

New shock bushes should be available from the same place you bought your shocks originally.

 

[Hayes]

No mystery, no thunk.

Just in case there's anyone out there who is NOT bored by this thread...

The cause and solution of/to my mystery thunk presented itself by chance yesterday.

After loading up the family for a short excursion and heading down the road, I immediately noticed my mystery thunk showing itself in a big way. I also noticed that my Slee spare tire carrier was rattling all over the place.

"Must have forgotten to latch the carrier."

Stopped, jumped out, and latched the carrier. The Slee carrier has a pin that secures the carrier closed, as well as an over center latch that snugs it down to the bumper nice and tight. Athough it will stay closed with only the pin, it obviously rattles around without the latch.

No more rattling carrier--and much less "thunk" under my left foot.

Getting to the point:

When the spare tire carrier rattles at all (even only slightly) the vibration is transferred down the frame rail, up through the body mount under the driver's side floor, and to my left foot.
It's really astonishing how prominent the thunk is. I won't even notice the carrier rattling around, but I can certainly hear and feel the rattle as a "thunk" under my foot.

The gradually increasing frequency and intensity of the thunk can be explained by the latch slowly stretching over time and becoming looser. I also wonder if the high temperatures around here lately have contributed to the loosenes a little bit by thermal expansion of the latch.

Tightened up the latch--thunk is 100% gone.

Hayes