Hi guys,
recently started having a very confusing car vibrations from the car.
At first I thought its the tire balance issue, re balanced all tires, seems to be good. Took to test drive, same thing car vibrates from 80 km/h speed.
Returned to the tire shop, checked again, found that 2 rims are slightly bent.
Took 2 rims to the shop where they where repaired, alighned.
One more time re balancing tires, everything perfect.
Took for the test drive, and to my disappointment the vibrations are still there. Its has a waving efect as you drive, not constant vibrating. Feels like comes from the bottom of the car.

What can be the issue? On my target is now the drive shaft. Any suggestions there?

Thanks.

 

Took the driveshaft for further inspection.
Found that all bolts where shaft connects gearbox are LOOSE.
It seemed that found the reason of vibrations, torqued them all and nothing.
Still having those damn vibrations and have no clue where to look for an issue.

 

OOPS.

Loose bolts, either left that way, or a result of said vibration, dunno.

The list could be longm but some suggestions:

Tailshaft centre bearing, old and not playing true.
Tyre compaound, had that on the R, and switching to a known brand, sorted.
Engine and transmission mounts, tired now.
Rear cradle bushes, the LARGE ones that insulate it o the body, they dont last forever.
Front cradle bushes. Not common, but maybe.

Good luck.

 

Shame it wasn’t the bolts, that would have been a cheap fix!
Have you checked rear engine mount (actually it’s really the gearbox mount) ?
If that’s OK, then there are two other parts of the drive shaft I would check.

EBC9040 Centre bearing
and
1CBC8996 Flexible jurid coupling.

These are both rubber and can deteriorate with age.

Good luck
Peter

 

I guess the lose bolts are a result of shaft vibration, because non repairs were made there , so could not leave that way.
Tires and rims also not the case, since i changed all rubber to new. This gave no result.

On my target are now the center shaft bearing. Problem is testing it, I guess only way is to buy new one, change it and hope it was tha case.

I visually checked the jurid rubber coupling, it looked good enough , no cracks. But you never know.

 

This sounds like something I traced for a long time.... in the end I found two things. The x300 is very sensitive to play in suspension bushings at various places. I have 3 running fine with no vibration now but it did effect 2 of my older ones... around 130K miles it really got worse. What ended up fixing the highway speed vibration was front upper shock mount bushings and in the second car it was rear wheel bearings a little loose. Two much side to side play. (there was not much play on either bushing or bearing... very sensitive)
I tried ball joints, passenger side transmission mount, Upper control arm bushings, tire rotation, balance, drive shaft, even unequal pressure in injectors, Alignment and tightened up steering stiffness. All to no avail. They all had issues but not the particular vibration I was tracking. It was very frustrating.

 

I'd also look closely at the tires, I have had internal belt separation that gave symptoms like you describe.

 

Whats interesting,
Went for a weekend drive this weekend.
Wanted to test vibrations in all circumstances.
I tightened the shaft bolts before and i must say after that vibrations got much less, but didnt went away.

I found very interesting behavior, while driving steady you feel it less, but when you get hills or uneven pavement and the car pushes itself to tarmac when you go uphill,suddenly feells much more significant.
At that moment when car gets down and rear suspension gets load, i feel suddenly more vibration .

That gives me thinking that maybe not the shaft is the point here, but the rear bearings.

 

Hi RB,

Just to add to the excellent suggestions you've received so far, here are a couple of other possibilities:

When the rear fulcrum bushings in the front crossbeam or engine cradle fail, they can allow tramlining and front end oscillations as the front cradle wiggles with road imperfections. These bushings are part 2 in this diagram:




Likewise, when the mounting bushings of the rear subframe/differential support fail, they can allow the entire independent rear suspension to wiggle, oscillate and shift while turning and affect steering precision. A common clue that these bushings have failed is differential gear noise audible in the passenger compartment due to the metal subframe coming into contact with the body. An easy way to see if these bushings have failed is to check for space between the body and the top of the subframe. If they're touching or very nearly touching, the bushings have failed. These bushings are part 14 in this diagram:



Please keep us informed. We're all curious to know what you figure out!

Cheers,

Don

 

Thanks Don for your advice,

The deeper I go to the forest the more trees i find growing around.

I guess i must somehow check the suspension one more time. Two weeks ago i was in MOT inspection, they checked the suspension quite good.
Found only that front bearings are little bit loose, and those shaft bolts. Basicaly nothing more.
I guess checking bushings of subframe requires special attitude.
Since vibration goes from the back side, i discarded the front bearings which needs to be adjusted slightly.
The noise from diff also is not present, so the deal is quite confusing.


Will go to the repair shop one more time for checking, if that doesn't help will probably buy a suspension rebuild kit and replace all at a time.

 

Took the car to the repair shop for inspection.

All bushings are in good condition, nothing wrong, no excessive wear.

One thing is suspicious - left rear axle joint has a slightly movement (photo attached).
Looks like the bearing movement, but it seems the joint moving itself.
I guess that could be the reason.



The shaft bearing seems to be fine, its moving when you push it but nothing critical. The rubber looks not cracked.


So i guess target is located, now must go for a axle rebuild.

 

Or start by replacing that universal joint, that's not too bad to do.